*Corr. Author’s Address: University of Novi Sad, Faculty of Technical Sciences, Trg Dositeja Obradovića 6, 21000 Novi Sad, Serbia, djokic@uns.ac.rs 466
Strojniški vestnik - Journal of Mechanical Engineering 70(2024)9-10, 466-482 Received for review: 2024-04-02
© 2024 The Authors. CC BY 4.0 Int. Licensee: SV-JME Received revised form: 2024-07-04
DOI:10.5545/sv-jme.2024.1006 Original Scientific Paper Accepted for publication: 2024-08-05
Analysis of Power Losses and Experimental Method for 
Determining Resistance in Electric Elevators
Đokić, R. – Vladić. J. – Jojić, T. – . Ličen, H. ml.
Radomir Đokić
1,*
 – Jovan Vladić
1
 – Tanasije Jojić
1
 – Hotimir ml. Ličen
2
1 
University of Novi Sad, Faculty of Technical Sciences, Serbia 
2 
TRC PRO, Serbia
To be able to carry out a high-quality analysis of the operation and design of elevator systems with a driving pulley, it is necessary to determine 
the size of the losses that occur in the drive mechanism and elevator guide rails. The paper defines an experimental procedure for determining 
the losses and the efficiency coefficient of elevator facilities depending on the relative load of the cabin in operational conditions. The 
experiment was carried out on a passenger elevator with a rated load of 320 kg and a lifting height of 28 m. An analysis of the resistance, 
i.e., the source of power losses in vertical lifting devices, was performed, the most significant of which occur and are especially pronounced 
in worm gear reducers and on the guiding system of the cabin and counterweight, where the type of guiding elements also has an influence. 
A particular problem is expressed due to the changing state of the contact surfaces (between the guide rails and the guide shoes) during 
exploitation and the eccentric loading of the cabin. Also, the paper analysed the obtained measurement results to determine the dependence 
of the efficiency coefficient of the facility concerning the relative load of the cabin.
Keywords: electric elevators, guide rails and driving mechanism resistances, efficiency determination 
Highlights
• 	 The complexity of designing and analysing elevator systems with driving pulley is manifested, among other things, in the 
occurrence of a large number of loss sources and the problem of determining their values.
• 	 Resistance values in elevators are particularly significant when eccentric cabin loading occurs and because they change 
during elevator operation, specifically changes in the vertical position of the cabin and counterweight.
• 	 The developed experimental method represents a unique procedure for determining total losses by measuring the torque on 
the drive motor shaft.
• 	 The specificity of the developed experimental method for determining total losses in electric elevators with worm gear reducers 
lies in the fact that a special problem arises in the case of self-locking transmission.
0  INTRODUCTION
Elevators are specific transport machines for vertical 
lifting and inclined transport (most often cargo). 
However, elevator shafts and inclined elevators are 
rarely used, i.e., the corresponding mine elevators 
that work in them. The main reason is that inclined 
shafts are longer for the same height, so they are 
more expensive to manufacture, and that inclined 
shafts require special and more expensive devices for 
cargo transport [1]. The needs of modern society have 
conditioned the development of different elevator 
constructions. Effective vertical mobility is crucial to 
developing and constructing high-rise buildings [2]. 
For buildings with many floors are being built, where 
elevators are necessary to transport passengers to a 
great height. There are many sources of power loss in 
vertical lifting devices. Fig. 1 shows some kinematic 
solutions of electric elevators; arrows show where the 
most considerable losses occur. Friction occurs in all 
places where there is relative movement of the contact 
surfaces of the elevator elements [3]. If, in addition 
to different kinematic solutions, the application of 
different transmissions as part of the drive mechanism 
is taken into account, it can be stated that for each 
specific case, it is necessary to perform an analysis 
and definition of the total resistance or the efficiency 
coefficient of the facility.
The primary goal of this paper is the development 
of a universal experimental method for determining 
the total resistances in electric elevators with worm 
gear reducers. The goal is that research and the 
developed method serve to put into practice the 
assessment of the condition of the existing elevators 
when periodic inspections are carried out. Also, 
research and results can serve as a basis for choosing 
the optimal parameters of elevators during their 
design.
Regarding the types of elevators from the point 
of view of drive systems, elevators without reducers 
are usually used for nominal velocities over 2.5 
m/s. In contrast, reduction devices (gearboxes) 
must be applied for lower velocities. Spur gears 
were occasionally used in the past, but with the 
development of design and manufacturing techniques, 
worm gears have become the accepted standard for 

Strojniški vestnik - Journal of Mechanical Engineering 70(2024)9-10, 466-482
467 Analysis of Power Losses and Experimental Method for Determining Resistance in Electric Elevators
elevators with gearboxes. In recent years, leading 
elevator manufacturers have put into production 
elevators with gearboxes that use double reduction 
with high-efficiency helical gears for nominal 
velocities up to 5 m/s [4]. The elevators are equipped 
with asynchronous AC motors, and the velocity is 
controlled by a frequency regulator. For example, in 
[5], the results of experimental research are given in 
which a comparison of energy consumption was made 
in the case of an elevator drive with and without a 
gearbox.
Fig. 1.  Places where friction occurs for different kinematic 
solutions in elevators
Depending on the applied kinematic solution 
in electric elevators (Fig. 1), where different total 
resistance values occur, there are techniques for the 
previous selection of the drive mechanism with a 
gearbox. In [6], the author specifies the conditions 
that the torque characteristic of a potential drive motor 
must meet. Among other requirements, it is stated that 
there should be a guaranteed excess of the locked-
rotor torque over the maximal load resistance moment 
at rest. Additionally, the presence of an excess of the 
motor’s maximal torque over the maximal torque 
required from the motor is emphasized. Also, the 
author lists the steps the designer must follow when 
choosing and gives general terms for different 
concepts (overhead machine, basement machine 
room, elevators without a machine room, etc.).
It should be noted that there is a very limited 
number of papers and studies in which authors 
are involved in determining the overall efficiency 
coefficient for electric elevators with worm reducers. 
Typically, research is based on the analysis and 
determination of losses in specific parts of elevator 
systems, such as guides, driving pulleys, deflecting 
pulleys, speed governors, reducers, etc.
In [7], power losses and their sources in the worm 
gear reducer are presented. These losses occur in the 
coupling of worm teeth and worm gear, in the bearings 
and seals, and in power losses during oil mixing. The 
total losses are determined for different values of input 
revolutions, output torque, and variations in oil types. 
Factors that significantly influence power losses 
include, above all, the type of material for gears and 
the geometry of the worm pair, the type and viscosity 
of lubricating oil, input revolutions, worm shape, load, 
temperature, etc. [8].
The drawback of a worm transmission is its 
relatively low efficiency, especially under extreme 
operating conditions, primarily related to high speeds. 
Significant sliding occurs between the worm and 
worm wheel, resulting in wear on the worm wheel and 
substantial power losses converted into heat [9] and 
[10]. The amount of energy transformed into heat is 
largely determined by the friction coefficient between 
the gear tooth faces.
In [11], the geometric characteristics of the 
worm gear reducer, the principle of operation and 
the theoretical basis for efficiency calculations 
were discussed. Based on conducted research and 
experiments, recommendations for improving the 
efficiency of the 2H-63 type worm transmission were 
developed.
In [12], power losses and their sources in worm 
gear reducers are presented. Considering that the 
operation of a worm transmission involves the 
line contact of coupled elements accompanied by 
significant sliding, the power losses in the coupling 
of the worm and worm wheel have the highest value. 
Formulas are provided for calculating individual 
power losses and the efficiency of the transmission. 
Furthermore, the issues of worm gear reducers were 
addressed in [13], in which models with concave-
shaped contact surfaces of the worm and convex-
shaped contact surfaces of the worm wheel teeth were 
analysed. The key characteristics of the proposed 
solution for the worm gear reducer lie in the fact 
that, due to the concave-convex contact, the entire 
side surfaces of the worm coil and the worm wheel 
teeth are involved in power transmission. Therefore, 
improved power transmission and lubrication 
properties can be expected, resulting in lower energy 
losses and less wear and tear.
In [14], self-locking properties have been 
implemented in a pair of worm gears that are 
connected to each other in an appropriate mesh 
pattern. The advantage lies in the simplicity of the 
system, whereby very high values of efficiency 

Strojniški vestnik - Journal of Mechanical Engineering 70(2024)9-10, 466-482
468 Đo kić,	R.	–	Vladić.	J.	–	Jo jić,	T .	–	.	Ličen,	H.	ml.
can be achieved, while conventional systems have 
significantly lower efficiency.
2  ANALYSIS OF RESISTANCE IN TRANSMISSION SYSTEMS 
AND GUIDING ELEMENTS IN ELEVATORS
The analysis of the lifting system with a driving pulley 
is very complex [15]. In this paper, based on Fig. 2, 
expressions for the forces in the hoist ropes as a 
function of the efficiency factor are provided, allowing 
us to observe the influence and, consequently, the 
significance of determining real resistance values.
The impact of resistances is encompassed by 
the efficiency coefficient for the gearbox, cabin, and 
counterweight, as well as all deflection pulleys and 
sheaves.
In Fig. 2, a generalized schematic representation 
of the elevator system is provided. The transmission 
ratio of the elevator shaft, denoted as i
S
 (which can 
also be referred to as the suspension ratio), is given as 
the ratio of the velocity of the supporting rope (hoist 
rope) v
G
 to the velocity of the cabin v
K
, i.e., i
S
 = v
G
/v
K
.
The following suspended loads are present in the 
elevator shaft: Q
t
 is the mass of the load in the cabin 
(payload), m
K
 the mass of the cabin, m
T
 the mass of the 
counterweight, m
G
 the mass of the hoist ropes, m
D
 the 
mass of the compensating rope or chain, m
H
 the mass 
of the travelling electrical cables, F
D
 the tensioning 
force of the compensating rope including the weight 
of the tensioning devices, and F
GB
 tensioning force of 
the speed governor.
The following equality applies between the mass 
of the cabin, the mass of the counterweight and the 
rated load:
 mm Q
TK
   , (1)
where Q is rated load for which the elevator is 
designed, and β coefficient taking account of 
the percentage of the rated load balanced by the 
counterweight (counterweight weight factor).
The relationship between payload (current mass 
of cargo in the cabin) and rated load is:
 QQ
t
  , (2)
where the λ represents the relative load (cabin load 
factor).
As shown in Fig. 2, the masses m
G
, m
D
, and m
H
 
are multiplied by a height factor κ or (1 – κ). When the 
cabin is at the bottom of the shaft, κ = 1 holds, while 
when it is at the top, κ = 0.
Fig. 2.  Generalized schematic representation of the elevator 
system with drive mechanism located above the shaft, [16] and 
[17]
The general expressions for the forces in the 
hoist ropes on the cabin and the counterweight side 
in stationary operating modes, according to Fig. 2 and 
[15] and [17], are as follows:
Sm Qs fm mg
F
KstK vK DH
DK U
s
v
         












11
1
1
K KU
vG B
S
RU
s
RU
G
S
sW
i
mg
i
v
2
1
1
2
1
1








 



 , (3)
 
Smsf mg
F
i
TstTvT D
DK U
s
KU
v
    


















1
1
2
1
2





S S
RU
s
RU
OU
s
G
S
OU
s
v
vv
mg
i


   






 

1
1
1
1
1
, (4)
where S
Kst
 is the stationary force in the hoist ropes on 
the cabin side, S
Tst
 is the stationary force in the hoist 
ropes on the counterweight side, s
v
 index of cabin 
movement direction, f
K
, f
T
 resistance coefficients of 
the cabin and the counterweight, η
OU
 efficiency of the 
deflection pulley, η
RU
 efficiency of the sheaves, and 
η
KU
 efficiency of the compensating ropes deflection 
pulley.
In the characteristic phases of the so-called motor 
operation mode (Q
1-2
), the values for λ and s
v
 in Eqs. 

Strojniški vestnik - Journal of Mechanical Engineering 70(2024)9-10, 466-482
469 Analysis of Power Losses and Experimental Method for Determining Resistance in Electric Elevators
(3) and (4) are taken as follows: λ = 1 and s
v
 = 1, for 
lifting a fully loaded cabin from the lowest station, 
and λ = 0 and s
v
 = –1, for lowering an empty cabin 
from the highest station.
In the characteristic phases of the so-called 
generator operation mode (Q
2-1
), the values for λ and 
s
v
 in Eq. (3) and Eq. (4) are taken as follows: λ = 0 and 
s
v
 = 1, for lifting an empty cabin to the highest station, 
and λ = 1 and s
v
 = –1, for lowering a fully loaded cabin 
to the lowest station.
Based on the forces in the hoist ropes on the cabin 
and the counterweight side, Eqs. (3) and (4), a general 
expression for the stationary torque reduced to the 
motor shaft can be obtained as:
 MS S
D
i
MstK st Tst
R
PU R
ss
PU R
ss
vt
vt
  
 

 


2
1
1
2
1
2


, (5)
where s
t
 is an index of the heavier side (s
t
 = 1 when the 
cabin side is heavier, s
t
 = –1 when the counterweight 
side is heavier), i
R
 transmission ratio of the gearbox, 
η
PU
 efficiency of the driving pulley, and η
R
, η'
R
 are 
efficiency of the gearbox during power flow Q
1-2
, and 
Q
2–1
, respectively.
This chapter presents the basic components 
and elements of the elevator that are the subject of 
this research, and it will analyse the resistances and 
the causes leading to their appearance. The most 
significant resistances occur in the transmission 
system (gearbox), which has particularly high 
values in worm gearboxes and on the cabin and 
counterweight guide rails.
Considerations in [18] indicate that individual 
losses in lifting systems (driving and deflection 
pulleys, bearings, guide rails, ropes, etc.) should 
be more precisely determined for various payloads 
(besides rated load) for all operating conditions (from 
acceleration to reaching nominal speed, deceleration 
(braking), stopping, etc., both ways).
The resistance of the elevator guidance system 
depends on the applied solution. Sliding shoes or 
roller guides are most often used to guide the cabin, 
Fig. 3. Due to the requirements for the straightness 
of the vertically placed guide rails, their length is 
limited during production, which means that the 
elevator cabin will encounter many joints of the guide 
rails on its path. Those joints are additional sources 
of resistance [19]. In addition to the guidance system 
type, the resistance also depends on the method and 
condition of lubrication of the contact surfaces, 
assembly, or regulation of the pre-tightening between 
the sliding shoe and the guide rails. A particular 
problem when defining the resistance occurs due 
to the changing state of the contact surfaces during 
the exploitation (wear, damage, and influence of the 
external environment) and the eccentric loading of the 
cabin (position of the centre of gravity of the load to 
the cabin suspension point).
Fig. 3.  Presentation of the cabin and counterweight guidance 
system; a) sliding guide shoes and the real state of the elevator;  
b) roller guides
Regarding the sliding shoes and their surface 
contact with the guide rails, highly non-linear 
hysteretic friction is shown, significantly hindering 
the transport quality. In [20], an experimental 
investigation of this type of phenomenon was carried 
out by measuring the force of contact friction between 
the sliding guide shoe and guide rail surfaces at 
different combinations of input parameters.
Typically, losses are calculated through efficiency 
coefficients of transmission. In the literature, they are 
usually estimated globally based on [15]: 
• For elevator worm gear reducer: η
R
 ≈ 0.45 to 0.80, 
where higher values of efficiency coefficient 
correspond to better quality of worm and worm 
wheel surfacing, smaller transmission ratios, and 
consequently, higher numbers of worm start. 
Also, higher values of efficiency coefficient are 
in the case of rolling bearings, greater forces, and 
higher worm rotations.
• Pulley losses: η
U
 ≈ 0.96 to 0.98, where higher 
values correspond to rolling bearings, ropes with 
a greater number of strands, thinner wires, and 
non-metallic rope cores.
• Losses in the elevator shaft, i.e., the cabin and 
counterweight guide rails (calculated through the 
overall transmission coefficient of efficiency in 
the elevator shaft),  typically in the range of η
VO
 = 
0.70 to 0.80. Lower values correspond to sliding 
guide shoes, the presence of compensating ropes 
or chains, their deflection pulleys or sprockets, 
and so on.
In addition to the above, the following is 
noteworthy :
• the accuracy of positioning of cabin and 
counterweight guide rails in the elevator shaft; 

Strojniški vestnik - Journal of Mechanical Engineering 70(2024)9-10, 466-482
470 Đo kić,	R.	–	Vladić.	J.	–	Jo jić,	T .	–	.	Ličen,	H.	ml.
• the variable position of the passenger or freight 
centre of gravity within the elevator cabin, 
resulting in varying loads on the guide rails and 
different resistances. 
Resistance on the cabin guide rails due to 
eccentric loading can be determined based on Fig. 4.
Fig. 4.  Frictional forces on cabin guide shoes
The total resistances that occur with eccentric 
loading of the cabin are:
 
FFF
mg
ee
h
tr tr tr
Q
Ql Qb
kl
  
 


 
42
2
12
        , (6)
where F
tr1
 = F
N1
 · μ
kl
 is frictional force on the cabin 
sliding guide shoe due to the eccentricity of the load 
position e
Q(l)
, F
tr2
 = F
N2
 · μ
kl
 frictional force on the 
cabin sliding guide shoe due to the eccentricity of the 
load position e
Q(b)
; e
Q(l)
, e
Q(b) 
the largest eccentricity 
of the load position across the cabin length and width, 
h spacing between sliding guide shoes in the vertical 
direction, μ
kl
 guide shoe friction coefficient, 
Fm eh
NQ Ql 1
2   
()
/ the normal force on the sliding 
guide shoe caused by eccentricity e
Q(l)
, and  
Fm eh
NQ Qb 2

()
/ the normal force on the sliding 
guide shoe caused by eccentricity e
Q(b)
.
Based on the expressions for the frictional force 
on the guide rails (Eq. (6)), it can be observed that the 
resistance values can vary from zero (no eccentricity) 
to some maximum value, which depends on the ratio 
of the cabin’s width to the spacing of the guiding 
elements on the cabin. It should be noted that these 
resistances can change during transport, especially 
in the case of passenger elevators, which further 
highlights the complexity of determining the total 
resistance of elevator systems.
3  POWER (TORQUE) LOSS IN ELEVATOR SYSTEMS  
AND TRANSMISSION EFFICIENCY
According to the resistance analysis discussed in the 
previous chapter, po wer transmission losses in the 
drive and transmission mechanisms of elevators and 
vertical transport machines occur primarily in
• Gearbox (most commonly present in the system), 
at:
• points of conjugate gear action, such as 
worm and worm wheel, 
• shaft bearings, due to friction, 
• points of friction between gears and oil inside 
the gearbox, 
• places where power is taken for auxiliary 
drives (e.g., lubrication pumps, etc.) if they 
exist. 
• Pulleys (driving pulley, deflection pulley, cabin 
and counterweight pulley in the case of 2:1 
suspension, other types of sheaves or sprocket for 
compensation rope or chain if they exist, pulleys 
for governor, etc.), at: 
• pulley bearings, due to friction, 
• at locations of rope bending [21] due to the 
rope stiffness. 
• Cabin and counterweight guide rails.
3.1  Load Torques and Losses in Elevator Systems
Fig 5 shows a schematic representation of an elevator 
system with power transmission using ropes. A 
distinction must be made between the high-speed 
part (System 1), which includes the motor M and the 
part of a gearbox G (worm), and the low-speed part 
(System 2), which includes the part of a gearbox 
(worm gear), the shaft mechanism S, and the load Q.
All torques and moments of inertia are reduced 
to the high-speed parts shaft of the electric motor 
(angular velocity ω
1
). The sum of the moments of 
inertia of the high-speed system components masses 
is denoted as J
1
, J
21
 represents the reduced moment 
of inertia of the masses of the worm gear and the 
driving pulley, while J
22
 represents the reduced 
moment of inertia of the (translational and rotational) 

Strojniški vestnik - Journal of Mechanical Engineering 70(2024)9-10, 466-482
471 Analysis of Power Losses and Experimental Method for Determining Resistance in Electric Elevators
moving parts masses which are located in the elevator 
shaft. The sum of J
21
 and J
22
 can be denoted as J
2
: 
J
2
 = J
21
 + J
22
.
The differential equation of motion of the 
elevator system, according to Fig. 5, can be expressed 
in general form as [22]:
• for motor operating mode Q
1–2
:
 MMMM JJ
d
dt
MGSQ
  () .
12
1

 (7)
• for generator operating mode Q
2–1
:
 
 MMMM JJ
d
dt
MGSQ
()
12
1

, (8)
where M
M
 is motor torque, M
G
 torque loss in the 
transmission, M
S
 torque loss in the elevator shaft, and 
M
Q
 load torque.
Fig. 5.  Schematic representation of elevator systems with power 
transmission through friction [22]
All torque values are reduced to the motor shaft.
The energy balance can also be separately written 
for Systems 1 and 2:
 MMMJ
d
dt
MG

21
1

, (9)
 MMMJ
d
dt
SQ 12
1


. (10)
In Eq. (9), M
2
 represents the torque acting at the 
meeting point of both systems. The same applies to 
M
1
, where M
1
 = –M
2
, considering that the sum of Eqs. 
(9) and (10) must give Eq. (7). Therefore, M
2
 is the 
torque acting on the shaft of the worm gear, which can 
be expressed from Eq. (10) as:
 sMMMJ
d
dt
QS 22
1


. (11)
Depending on the magnitude of individual terms 
in this expression, M
2
 can be greater or less than zero. 
If M
2
 acts in the opposite direction of rotation, energy 
is transferred from system 1 to system 2, meaning 
that the power flow is from system 1 to system 
2, symbolically denoted as Q
1–2
. If M
2
 acts in the 
direction of rotation, energy is transferred from system 
2 to system 1, and this power flow is symbolically 
denoted as Q
2–1
. This means that the direction of 
power flow is precisely defined at each moment, 
and it holds that: for Q
2–1
 sgn M
2
 = –sgn ω
1
, and for  
Q
2–1
 sgn M
2
 = +sgn ω
1
.
The weights located in the elevator shaft 
create a torque on the driving pulley (load torque), 
according to the forces in the ropes on the side of 
the cabin/counterweight and Eqs. (3) to (5), which, 
when reduced to the motor shaft, has the following 
magnitude:
  
M
D
ii
mm Q
mm mg
Q
RS
KT
DH G


  
         


2
1
12 12 1

  . (12)
By substituting Eq. (1) into Eq. (12), the final 
value is obtained in the form:
 
M
D
ii
Qm
mm
Q
RS
D
HG


      

     
2
1
12
12 1
 
        

g. (13)
By introducing the term “nominal load torque”:
 M
D
ii
Q
Qn
RS



2
1
1 () ,  (14)
the load torque becomes:
 MM
QQ n












 
1
, (15)
where: 


 


mi mm
g
GS DH
() Q 1
, 
and 


  


22
1
mi mm
g
GS DH
() Q
.
Losses in the elevator shaft are caused by friction 
on the cabin and the counterweight guides, in the 
bearings of the deflection pulleys and sheaves, as well 
as due to the bending of the ropes over the driving 
and deflection pulleys and sheaves. The assumption is 
that the torque loss (resistance) increases linearly with 
increasing load, i.e., that the coefficient of friction 
remains independent of the magnitude of the load. 
This assumption cannot always be fully applied to the 
friction on the guides since the position of the load in 
the cabin can play a role; that is, additional forces can 
occur due to the occurrence of asymmetric loading of 
the cabin.
In general, the coefficient of friction will 
undoubtedly change with the corresponding sliding 

Strojniški vestnik - Journal of Mechanical Engineering 70(2024)9-10, 466-482
472 Đo kić,	R.	–	Vladić.	J.	–	Jo jić,	T .	–	.	Ličen,	H.	ml.
velocity (the cabin velocity). The sliding velocities at 
different locations have different magnitudes at any 
given moment, so determining them would overly 
complicate the calculation. Therefore, a multiplier v
S
 
dependent on the velocity is introduced for the torque 
loss, whose course of change (values) still requires 
detailed examination.
Some type of total friction coefficient can be 
calculated for the elevator shaft. The forces acting in 
the shaft, multiplied by the total friction coefficient 
μ
S
∙ν
S
, result in the friction force in the shaft, which 
would include the influence of individual friction 
coefficients for each deflection pulley, sliding guide, 
etc., for which there is already some empirical data.
Here, d’Alembert’s apparent force originating 
from the masses on the counterweight side has 
retained a negative sign. This is because, for example, 
when dω
1
/dt > 0, the apparent force loads the contact 
surfaces on the cabin side while it unloads them on the 
counterweight side. J
T
 denotes the moment of inertia 
of the masses on the counterweight side reduced to the 
shaft of the electric motor.
The total torque loss of the elevator shaft has the 
form:
 
MM vv M
JJ
d
dt
SC SS SQ n
KT
 









 











	




1
1
1
sgn, , (16)
where:
 MM
CQ nS T




 
 1
, 
      













1
1
2 Q
mg im gm gm g
F
GS DH K
D
, 
       



1
1
Q
mg im gm g
GS DH
. 
χ is the ratio of total moments of inertia in the 
elevator shaft on the side of the counterweight and on 
the side of the cabin.
Considering that roughly estimated, J
K
 ≈ J
T
 and  
χ = 1, it follows:
 JJ
KT
  0. (17)
Since the values for J
K
 and J
T
 are already small 
compared to the total moment of inertia of the elevator 
system, the difference J
K
 -  χJ
T
 multiplied by the 
factor μ
S
×v
S
, which is usually less than 0.1, becomes 
negligibly small. With this justified neglect, the torque 
loss of the elevator shaft becomes:
 MM vv M
SC SS SQ n
 








 



1
1
sgn. (18)
The torque loss of the elevator shaft is practically 
independent of the moments of inertia of the masses 
located within the shaft.
Losses in the transmission consist of losses due 
to gear meshing, losses due to friction in the bearings 
and losses in the so-called “idling”.
Losses due to gear meshing occur on the contact 
surfaces between the worm and the worm wheel. 
The torque loss due to meshing can be expressed as 
a function of the torque on the worm wheel shaft M
2
:
 MM
VZ
  
21
sgn,  (19)
where:  







1
i
d
d
i
d
d
R
R
S
R
S
R
 , and d
S
 is the pitch 
 
diameter of the worm, the d
R
 pitch diameter of the 
worm wheel, and μ coefficient of friction.
The value of the friction coefficient depends not 
only on the quality of the surface and the viscosity 
of the oil but also on the sliding velocity between the 
friction surfaces, i.e., from the number of revolutions.
The torque loss of worm pairs, according to Eq. 
(19), is linear only for small values of M
2
, namely 
when viscous friction is present. In the presence of 
dry and viscous friction, the torque loss increases 
exponentially, i.e., the factor Ω is, in a sense, also 
dependent on |M
2
|.
The torque loss due to friction in the bearings can 
also be expressed as a function of the torque M
2
:
 MC M
LagL ag
 
21
sgn,  (20)
where C
Lag
 is constant dependent on the geometric 
dimensions of the worm gear.
Losses in the so-called “idling” occur due to 
resistance when parts move through oil in the gearbox. 
These losses depend on the geometric dimensions of 
the gearbox, the viscosity of the oil, and the rotational 
speed and can be expressed as:
 MC n
00 1
3
  , (21)
where n
1
 is the number of worm rotations, and C
0
 is 
constant, dependent on the dimensions of the gearbox.
The total torque loss of the gearbox is the sum of 
three losses given by Eqs. (19) to (21).
For this study, it is important to mention that 
the magnitude of the torque M
2
 also depends on 
the angular acceleration J
2
, according to Eq. (11). 
However, the experimental method applied in this 

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473 Analysis of Power Losses and Experimental Method for Determining Resistance in Electric Elevators
 1
11
1 




MM
M
MM
M
SG
Q
SG
Q

    . (26)
Eq. (8) and Eq. (25) for generator operation mode 
(Q
2–1
) give:
 










MMM
M
MM
M
MM
M
QSG
Q
SG
Q
SG
Q
       11 . (27)
From Eqs. (26) and (27) follows:
 
1
11 2
1



      . 
The last dependency holds true only if the relative 
load of the cabin (λ) and the vertical position of the 
cabin in the shaft are the same for Q
1–2
 and Q
2–1
 while 
the direction of motion is different, i.e., when all 
transmission losses are independent of the load.
Fig. 6.  Principled	f o rm	o f	dependence	η=f(λ)	with	the	directio n	o f	
elevator cabin movement and the direction of power flow through 
the drive mechanism, as parameters; a) transmission that is not 
self-locking under nominal load; b) self-locking transmission even 
under nominal load [15]
In Fig. 6, it can be observed that the trend of 
efficiency for upward and downward movement is 
not identical. Specifically, it cannot be confirmed the 
commonly used assumption that with a 50 % load 
compensation (β = 0.5), the torque resistance of the 
system at the drive motor shaft is the same when 
study is related to determining the total losses in the 
stationary operating mode of elevators.
3.2  Elevator Efficiency Coefficient
By introducing the term “stationary shaft efficiency 
coefficient” η
S
 [22], which would represent the ratio of 
the load torque M
Q
 to the torque M
Q
+M
S
 with which 
the elevator mechanism acts on the drive unit, its 
value can be written as:
 
S
Q
QS
S
Q
M
MM
M
M




1
1
. (22)
Similarly, the “stationary gearbox efficiency 
coefficient” η
G
 can be introduced [22], which at Q
1–2
 
(Fig. 5) represents the ratio of the torque at the worm 
wheel to the torque at the worm shaft in the stationary 
state, i.e., when dω
1
/dt = 0:
 
G
QS
QSG
G
QS
MM
MMM
M
MM






1
1
. (23)
The overall efficiency is the product of η
S
 and η
G
, 
that is, the ratio of the torques M
Q
 and M
M
 for the Q
1–2
 
direction of power flow. 
 
  











SG
Q
QS
QS
QSG
Q
QSG
SG
Q
Q
M
M
MM
MM
MMM
M
MMM
MM
M
M
M
1
1
. (24)
Similarly, the overall efficiency of the Q
2–1
 
direction of power flow is obtained in the same way, 
and it is given by: 
  
M
M
M
Q
. (25)
The relative load of the cabin has a significant 
impact on the efficiency of each elevator system. The 
efficiency is highest at nominal load and empty cabin, 
while at half the rated load of the cabin, the value of η 
drops and may even reach zero, as shown in Fig. 6. As 
already mentioned, the power flow through the drive 
mechanism also has a certain impact on the magnitude 
of the efficiency.
Based on Eqs. (7), (8), (24), and (25), a common 
(universal) expression can be found that represents the 
relationship between the transmission efficiency in 
the generator (Q
2–1
) and motor mode (Q
1–2
). From Eq. 
(24), the following equality can be written:

Strojniški vestnik - Journal of Mechanical Engineering 70(2024)9-10, 466-482
474 Đo kić,	R.	–	Vladić.	J.	–	Jo jić,	T .	–	.	Ličen,	H.	ml.
the cabin is fully loaded moving upward and when 
an empty cabin descends downward. In the case of 
an empty cabin, the losses in the elevator shaft are 
significantly lower than when fully loaded. Hence, 
the efficiency of the entire system will be more 
favourable.
A special problem arises in the case of self-
locking transmission (most often worm gear). 
Generally, for pulleys, gear pairs, and transmissions 
with high η, there is no difference in the efficiency 
coefficient depending on the direction of the power 
flow. At the same time, this must be considered for the 
worm gear transmission. Therefore, based on Fig. 5, 
the following characteristic cases of power flow may 
occur [15]:
• from the drive electric motor to the cabin or 
counterweight, Fig. 7a; 
• from the cabin, i.e., the counterweight to the drive 
electric motor, Fig. 7b; 
• from the drive electric motor to the transmission 
and from the cabin, i.e., the counterweight to the 
transmission (case of self-locking), Fig. 7c.
Fig. 7.  Power flow in elevators: a) from the drive electric motor to 
the cabin or counterweight, b) from the cabin or the counterweight 
to the drive electric motor, and c) from the drive electric motor to 
the transmission and from the cabin or the counterweight to the 
transmission
Based on the above, it can be observed that there 
is significant complexity associated with determining 
losses or the efficiency of vertical lifting systems 
with a driving pulley, leading to the need for elevator 
manufacturers to experimentally determine the 
values and the character of changes in the efficiency 
of all transmission elements, especially the worm 
gear reducer and elements for guiding the cabin and 
counterweight, or to foresee appropriate experimental 
measurements on installed facilities in operation. The 
following section defines an experimental method for 
determining the magnitude of resistance or the overall 
efficiency coefficient of elevator facilities.
4  EXPERIMENTAL METHOD FOR DETERMINING  
RESISTANCE IN ELEVATORS
Determining the resistance in elevators is based on 
the consequence of frictional resistance in the cabin 
and counterweight guides, as well as in the drive 
mechanism. In this manner, the total (equivalent) 
movement resistance is determined using specially 
designed measuring equipment for various cabin 
loads. The measurement procedure involves 
measuring the resistance magnitude by lifting the 
cabin to the desired height (position) via the driving 
electric motor. Subsequently, manual disengagement 
of the drive is performed (separation of brake shoes 
using a lever) in the machine room while the cabin 
is held at the same height via the flywheel. Using 
a portable electric pipe threader connected to the 
flywheel via a torque transducer, the elevator cabin 
is lifted/lowered at a slow speed to a specific height 
(ten or more revolutions of the flywheel), after which 
the brake is reactivated. In this manner, the torque 
transducer measures the value of the total resistance 
for the current position and load of the cabin.
The dimensions of the measuring equipment 
and especially the elements for connection with 
the flywheel or the shaft must correspond to the 
characteristics of the drive mechanism for the specific 
elevator. It is necessary to foresee an appropriate 
method of loading the cabin. Various types of 
loads can be used to allow variation in the size and 
eccentricity of the cabin load.
The results obtained through this experiment are 
used in the field of elevator design, reconstruction, 
and maintenance. For the computational analysis of 
elevator driving characteristics, especially concerning 
the “driving comfort” in passenger elevators, 
knowing the real resistance values is necessary, as 
their influence (η
uk 
= 0.45 to 0.80) is of the same 
order of magnitude as the influence of the rated load 
of the elevator (Q), and often greater in elevators in 
operation when the relative cabin load is λ ≈ 0.5.

Strojniški vestnik - Journal of Mechanical Engineering 70(2024)9-10, 466-482
475 Analysis of Power Losses and Experimental Method for Determining Resistance in Electric Elevators
Thus far, in practice, the results of laboratory tests 
of resistance, i.e., the efficiency coefficient, which 
is carried out separately, are most often used, e.g., 
for part of the drive mechanism in the laboratories 
of transmission manufacturers and for the elevator 
shaft with models in the laboratories of elevator 
manufacturers or specialized institutions.
Fig. 8.  Driving machine of passenger elevator
The experimental method presented in this paper 
includes measurements performed on a passenger 
elevator with a rated load of 320 kg, a maximum 
projected lifting velocity of 1.2 m/s, and a lifting 
height of 28 m, whose drive mechanism (worm gear 
reducer coupled with an asynchronous electric motor) 
is shown in Fig. 8. Other significant characteristics 
of this elevator can be seen in Table 1. It should be 
noted that it is a reconstructed elevator whose rated 
load is reduced compared to the designed load (450 
kg). Additionally, mechanical weighing devices 
were installed during the reconstruction to limit the 
load, and the weights of the cabin and counterweight 
were modified. Since, in most cases, the elevator is 
used to transport one person, in order to save energy, 
elevator technicians have reduced the value of the 
counterweight weight factor (β) compared to usual 
values.
Table 1.  Elevator technical characteristics
Driving electric 
motor
Power: 7.5 kW
Number of revolutions: 910/210 rpm
Nominal torque: 70.2 Nm
Cabin m
K
 = 740 kg
Counterweight m
T
 = 775 kg
Hoist ropes
z = 4 pieces
d = 13 mm (114 wires per cross-section)
Unit mass: 0.56 kg/m
Compensation chain
Type: welded chain (with links through which a 
hemp rope is spliced).
z = 1 piece
Unit mass: 2.25 kg/m
Number of floors/
entrances
10/10
Diameter of the drive 
pulley:
D = 650 mm
Cabin dimensions: 1030 mm × 1420 mm × 2200 mm
Cabin guide rails:
┴
 65 mm × 90 mm × 14 mm
Counterweight guide 
rails:
┴
 50 mm × 50 mm × 6 mm
Fig. 9.  Arrangement of measuring equipment; a) general arrangement of measuring points, and b) detailed view of the kinematic chain

Strojniški vestnik - Journal of Mechanical Engineering 70(2024)9-10, 466-482
476 Đo kić,	R.	–	Vladić.	J.	–	Jo jić,	T .	–	.	Ličen,	H.	ml.
4.1  Measuring Equipment and the Method for Measuring 
Data Acquisition
For the “stationary” measurements and experimental 
determination of the values and character of the 
change in efficiency, or losses, primarily of the worm 
gear reducer and cabin and counterweight guiding 
elements, the following equipment was used:
• Measuring lever, position 1 (Fig. 9),
• Rotating torque transducer, measuring range up 
to 200 Nm, position 2 (Fig. 9),
• Portable electric pipe threader, used for 
continuous rotation of the flywheel, and thus 
lifting and lowering of the cabin/counterweight, 
position 3 (Fig. 9),
• Measuring amplifier HBM MVD2555, accuracy 
class 0.1, position 4 (Fig. 9),
• Software for acquisition and processing of 
measuring signals, HBM catmanEasy-AP,
• Laptop for storing the measuring signals (torques) 
collected from the flywheel of the electric motor 
and from the force measurement device in the 
suspension ropes, position 5 (Fig. 9),
• Rope force measuring device of S-type HBM 
S9M, measuring range 0.5 kN to 50 kN,
• Universal 8-channel measurement amplifier 
HBM SPIDER 8.
The measuring lever is designed and fabricated 
to allow a simple and sturdy connection with the 
flywheel of the electric motor and to enable easy and 
quick attachment of the torque measurement device at 
its midpoint. 
Fig. 10a shows the design of the measuring lever 
in the form of a technical drawing as a basis for its 
fabrication, while Fig. 10b depicts the measuring lever 
with the torque measurement device and the driving 
element (portable electric pipe threader) during 
measurement, mounted on the flywheel of the electric 
motor.
After manual disengagement of the brake lever 
(Fig. 11a), the portable electric pipe threader (Fig. 
10b) is activated, whose torque is transmitted to the 
flywheel through the torque transducer (position 
2, Fig. 9), thereby lifting or lowering the cabin. 
The measurement signal (change in torque on the 
flywheel) from the torque transducer is directed to the 
measurement amplifier HBM MVD2555, and from 
there, through the data acquisition and processing 
software HBM catmanEasy-AP, stored in the 
computer memory (Fig. 11b).
Fig. 10.  Measuring equipment used for the “stationary” 
measurements; a) technical drawing of measuring lever, and  
b) lever mounted on the flywheel of the electric motor
Fig. 11.  Measuring point: a) brake with the release lever, and  
b) part of measuring equipment
Before the beginning of the experiment, i.e., 
before determining the total resistances based on 
torque measurement on the shaft of the drive electric 
motor, the weight of the cabin and counterweight 
was measured (checked) using a force measuring 
device on the ropes, as shown in Fig. 12a. The 
measurement was performed by mounting the device 
on the suspension ropes (from the first to the fourth) 
directly above the cabin. The device was connected to 
the universal measurement amplifier SPIDER 8; then 
the measurement data were collected in the memory 
of the laptop, position 5 (Fig. 9). The values of forces 
(weights) in individual ropes were read, and their sum 

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477 Analysis of Power Losses and Experimental Method for Determining Resistance in Electric Elevators
provided the exact (actual) weight of both the cabin 
and the counterweight.
Fig. 12.  Measuring rope tension force: a) device for measuring 
(checking) the mass of the cabin and counterweigh,  
b) the position of the mounted device.
It should be noted that the measurements were 
conducted for cases when the cabin was at the bottom 
level (ground floor), approximately at the midpoint 
of the lifting height (14 m), and at the top level (9
th
 
floor). For all these cases, the cabin was lifted via an 
electric pipe threader for more than ten revolutions 
of the flywheel (shaft) of the drive motor and then 
lowered also for several revolutions of the flywheel. In 
the case where the cabin was at the top level, lowering 
was performed first, followed by lifting.
4.2  Protocols and Results of the Experiment
This experiment and the measurement results 
demonstrate that determining the resistance in 
elevators can be conducted on the drive machine in 
the elevator machine room. This way, it is possible to 
determine the total (equivalent) movement resistance 
using specially designed measuring equipment 
for various loads and cabin height positions. The 
experiment enables direct measurement of resistance 
in cases where the load torque is greater than the 
friction torque, as well as measurement of resistance 
for the reverse relationship of these torques for the 
case of the so-called “self-locking” drive.
In Fig. 13, a schematic representation of a 
passenger elevator with marked levels (floors) is 
shown.
The measurement results and determination of 
the total elevator efficiency for stationary conditions 
in this study are presented for three characteristic 
cases (cabin positions), with different loads in the 
cabin and without any load. The results will be shown 
for cases of lifting and lowering the empty cabin, and 
the cabin loaded with weights of 80 kg, 160 kg, 240 
kg, and with the rated load (320 kg), based on which 
the total resistances will be determined in the form of 
the coefficients of efficiency. The characteristics of 
the selected experimental cases are as follows:
Fig. 13.  Schematic representation of the elevator shaft
I)  Lifting the cabin from the ground floor (bottom 
level) for more than 10 revolutions of the drive 
motor shaft (flywheel), then lowering for the same 
value and returning to the initial position. Upon 
stopping, the brake lever was simultaneously 
disengaged. The experiment was repeated for 

Strojniški vestnik - Journal of Mechanical Engineering 70(2024)9-10, 466-482
478 Đo kić,	R.	–	Vladić.	J.	–	Jo jić,	T .	–	.	Ličen,	H.	ml.
both the empty cabin and the cabin loaded with 
weights of 80 kg, 160 kg, 240 kg, and 320 kg.
II)  Lifting the cabin from the midpoint of the lifting 
height (middle level) for more than 10 revolutions 
of the drive motor shaft (flywheel), then lowering 
for twice the number of revolutions of the motor 
shaft, and then lifting again and returning to the 
initial position. Upon stopping, the brake lever 
was simultaneously disengaged. The experiment 
was repeated as in case (I) for both the empty 
cabin and the cabin loaded with weights of 80 kg, 
160 kg, 240 kg, and 320 kg.
III)  Lowering the cabin from the 9th floor (top 
level) for more than 10 revolutions of the drive 
motor shaft (governor), then lifting for the same 
value and returning to the initial position. Upon 
stopping, the brake lever was simultaneously 
disengaged. The experiment was repeated as in 
cases (I) and (II) for both the empty cabin and the 
cabin loaded with weights of 80 kg, 160 kg, 240 
kg, and 320 kg.
The activity flow during experimental 
measurements can also be illustratively presented 
through the diagram given in Fig. 15.
As a result of the conducted experimental tests, 
changes in torque on the shaft (flywheel) of the 
elevator’s drive motor are presented in the following 
Figs. 16 to 18. 
Fig. 15.  Activity flow diagram for experimental measurement
The results correspond to all three cases of 
movement, i.e., lifting/lowering of the cabin at the 
bottom level (ground floor), at the midpoint of the 
lifting height, and at the top level (9
th
 floor), for 
five different load values. From the diagrams, it can 
be observed that when engaging and disengaging 
the electromotor-driven threading machine (start 
Fig. 14.  Passenger elevator parameters relevant for determining total resistances:  
a) elevator drive mechanism, and b) forces and different positions of the cabin

Strojniški vestnik - Journal of Mechanical Engineering 70(2024)9-10, 466-482
479 Analysis of Power Losses and Experimental Method for Determining Resistance in Electric Elevators
of movement), there is a sudden peak in the torque 
value registered on the measuring device (torque 
transducer), which can be attributed to dynamic 
influences, i.e., acceleration/deceleration of 
translational and rotational masses of the elevator 
system. Under “stationary” conditions, a relatively 
steady total torque value is reached, which is the result 
of the sum of lifting “relative” cabin load and total 
resistances reduced to the motor shaft.
The parts of the diagram related to the elevator’s 
stationary operating regime are used to determine 
the average values of the total elevator efficiency, as 
shown in Chapter 4.3.
Table 2 gives the averaged values of the measured 
torque on the drive motor shaft, obtained from the 
diagrams shown in Figs. 16 to 18 for the steady-state 
operation, i.e., lifting and lowering the cabin. The 
measured torque values are shown for five different 
cabin loads and three different cabin positions.
Table 2.  Average values of the measured torque on the drive motor 
shaft
Q
t
  
[kg]
M
m
 [Nm]
Bottom level Middle level Top level
Lifting Lowering Lifting Lowering Lifting Lowering
0 2.95 –11.14 1.72 –11.69 –11.48 1.43
80 14.78 –0.28 12.42 –0.30 –1.69 12.26
160 24.45 5.71 23.71 7.91 6.95 24.17
240 39.29 14.00 36.57 15.15 14.84 35.83
320 52.76 21.87 49.03 21.93 21.51 48.85
4.3  Determination of the Elevator Overall Efficiency Based 
on the Measurement Results
Based on the measurement results depicted in Figs. 
16 to 18 and Table 2, it is possible to determine the 
overall efficiencies of the elevator for different cases 
of motion and various loads of the cabin in stationary 
operating modes of the elevator. The theoretical basis 
for determining the overall efficiencies is provided 
in Chapter 3.2. The measured values of the torque 
on the shaft of the drive motor (given in Table 2) for 
the motor operation mode (Q
1–2
 direction of power 
flow) represent the sum of the moments M
Q
+M
S
+M
G
. 
Determining the overall efficiency of the elevator 
based on the developed experimental method is done 
according to Eq. (24):
  
M
M
Q
M
. 
Fig. 16.  Measurement of the total torque on the drive motor 
shaft during the lowering/lifting of the elevator cabin  
at the bottom level for various loads (Case I)
Fig. 17.  Measurement of the total torque on the drive motor shaft 
during the lowering/lifting of the elevator cabin  
at the middle level for various loads (Case II)
Fig. 18.  Measurement of the total torque on the drive motor 
shaft during the lowering/lifting of the elevator cabin  
at the top level for various loads (Case III)

Strojniški vestnik - Journal of Mechanical Engineering 70(2024)9-10, 466-482
480 Đo kić,	R.	–	Vladić.	J.	–	Jo jić,	T .	–	.	Ličen,	H.	ml.
The values of the overall efficiency for the 
generator operation mode, i.e., for Q
2–1
, are obtained 
from Eq. (25):
  
M
M
M
Q
. 
Due to the equal weights per meter of the 
supporting ropes and compensating chain of the 
subject elevator (m
G 
= m
D
, Table 1), and due to the 
1:1 suspension system of the cabin and counterweight 
(i
S 
= 1), Eq. (13) for determining the load torque 
(load torque reduced to the shaft of the drive motor) 
becomes (m
H
 can be neglected due to its small value):
  M
D
i
Qg
QgD
i
Q
RR

 
 2
1
2
()
()
, 

 (28)
where D = 650 mm is the diameter of the driving 
pulley (Table 1), and i
R
 = 27.7 is the transmission ratio 
of the reducer.
Table 3.  Overall elevator efficiency coefficients at the bottom level
Q
t
 
[kg]
λ [-]
M
Q
 
[Nm]
η [-]
Q
1–2
Q
2–1
Lifting Lowering Lifting Lowering
0 0 –4.03 - 0.36 0.73 -
80 0.25 5.18 0.35 - - 0.05
160 0.50 14.39 0.59 - - 0.40
240 0.75 23.60 0.60 - - 0.59
320 1.00 32.80 0.62 - - 0.67
Table 4.  Overall elevator efficiency coefficients at the middle level
Q
t
 [kg] λ [-]
M
Q
 
[Nm]
η [-]
Q
1–2
Q
2–1
Lifting Lowering Lifting Lowering
0 0 –4.03 - 0.34 0.43 -
80 0.25 5.18 0.42 - - 0.06
160 0.50 14.39 0.61 - - 0.55
240 0.75 23.60 0.65 - - 0.64
320 1.00 32.80 0.67 - - 0.67
Table 5.  Overall elevator efficiency coefficients at the top level
Q
t
 
[kg]
λ [-]
M
Q
 
[Nm]
η [-]
Q
1–2
Q
2–1
Lifting Lowering Lifting Lowering
0 0 –4.03 - 0.35 0.35 -
80 0.25 5.18 0.42 - - 0.33
160 0.50 14.39 0.60 - - 0.48
240 0.75 23.60 0.66 - - 0.63
320 1.00 32.80 0.67 - - 0.66
The counterweight weight factor and the relative 
load of the cabin (cabin load factor) are determined 
based on Eqs. (1) and (2).
Fig. 19.  The change in the total efficiency of the elevator  
for different operating modes and cabin movements  
at the bottom level
Fig. 20.  The change in the total efficiency of the elevator  
for different operating modes and cabin movements  
at the middle level
Fig. 21.  The change in the total efficiency of the elevator  
for different operating modes and cabin movements  
at the top level
The calculated values of the overall elevator 
efficiency coefficients are given in Tables 3 to 5.
The measurement results with calculated values 
of the total efficiency (η), presented in Tables 3 to 

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481 Analysis of Power Losses and Experimental Method for Determining Resistance in Electric Elevators
5, can also be depicted graphically in Figs. 19 to 
21. Based on the tables and diagrams (in addition to 
numerous values), it can be concluded that the change 
in the total efficiency of the elevator depending on the 
cabin load factor is not linear and corresponds to the 
theoretical considerations provided in the first part of 
the paper. By increasing the relative cabin load, i.e. 
by moving the value of the cabin load factor away 
from the counterweight weight factor, the value of 
the overall efficiency coefficients of the elevator also 
increases.
5  CONCLUSIONS
The measurements and method presented in the paper 
are based on determining the resistance in elevators 
due to friction in the cabin, counterweight guide rails, 
and part of the drive mechanism. In this way, the total 
(equivalent) movement resistance is determined using 
a specially-made measuring tool for different cabin 
loads. The experiment represents a unique method for 
determining total losses by measuring the torque on 
the shaft (flywheel) of the drive motor.
The total resistance in elevators depends on 
numerous factors, such as the elevator’s design, 
the type of transmission in the drive mechanism, 
the relative velocity of the contact surfaces, the 
type of cabin and counterweight sliders, the size 
and eccentricity of the cabin load, lubrication, 
wear and tear, the condition of the contact surfaces, 
temperature, etc. Through the presented procedure and 
experimental research, it is possible to determine the 
real values of these parameters for static conditions.
This manuscript specifically addresses a method 
for determining total losses in electric elevators with 
a worm reducer. Such systems involve two power 
flows–from the drive motor to the driving pulley and 
vice versa (depending on whether the motor operates 
in motor or generator mode). A particular issue arises 
in the case of self-locking transmission.
This research and the unique method can serve in 
the future to introduce an assessment of the condition 
of existing elevators in practice through measurements, 
for example, during periodic inspections. Based 
on the large amount of data obtained from these 
measurements, it is possible to establish a basis for 
improving the conditions for designing more efficient 
elevator systems in terms of optimal parameter 
selection, energy savings, maintenance, etc.
6  ACKNOWLEDGEMENTS
This research has been supported by the Ministry of 
Science, Technological Development and Innovation 
(Contract No. 451-03-65/2024-03/200156) and the 
Faculty of Technical Sciences, University of Novi Sad, 
through project “Scientific and Artistic Research Work 
of Researchers in Teaching and Associate Positions at 
the Faculty of Technical Sciences, University of Novi 
Sad” (No. 01-3394/1).
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