
HangZhou
Power Transmission Group 
Groove
dimensions To DIN2211 (ISO 4183) 
 


TYPE 
DP (mm) 
alpha?/B> 
f 
E 
g 
h 
b 
SPZ 
<
80 
34 
8,00 
12,00 
9,7 
9 
2,00 
>
80 
38 
8,00 
12,00 
9,9 
9 
2,00 
SPA 
<
118 
34 
10,00 
15,00 
12,7 
11 
2,75 
>
118 
38 
10,00 
15,00 
12,9 
11 
2,75 
SPB 
<
190 
34 
12,50 
19,00 
16,1 
14 
3,50 
>
190 
38 
12,50 
19,00 
16,4 
14 
3,50 
SPC 
<
315 
34 
17,00 
25,50 
21,9 
19 
4,80 
>
315 
38 
17,00 
25,50 
22,3 
19 
4,80 

 
SERVICES FACTORS 
CONDITIONS OF OPERATION 
8 hours per day 
16 hours per day 
24 hours per day 
uniform torque 
variable torque 
highly variable torque 
uniform torque 
variable torque 
highly variable torque 
uniform torque 
variable torque 
highly variable torque 
Normal electric motor (Cd/Cn)
<=2 
1  1.12 
1.25 
1.12 
1.25 
1.40 
1.18 
1.32 
1.50 
Freqent start/stops or
reversing 
1.18 
1.25 
1.40 
1.25 
1.40 
1.60 
1.32 
1.40 
1.70 
Electric motor with a high startup torque, or motor
asynchronous, single or twin cylinder diesel
engine 
1.18 
1.32 
1.50 
1.32 
1.50 
1.70 
1.40 
1.60 
1.80 
Reversals or frequent start/stops on a motor with a
high startup torque 
1.32 
1.50 
1.70 
1.50 
1.70 
1.90 
1.80 
1.80 
2 

 

INSTALLATION
RECOMMENDATIONS
Progressively tension the trapezoidal
belt : Spin the belt for 15 minutes, apply tension. Verify the
tension to avoid belt slip, which will quickly cause wear
Check
that :
 The sides of the groove are smooth, clear of
paint, rust or metal burrs.
 The adjustment of the tension is made at the
motor pulley end. If this is impossible, the installation of a
tensioning pulley of the same profile is recommended. It’s diameter
should be superior to the minimum indicated diameter.
 The profile has not changed after
replacement of the pulley set.
 The alignment of the pulleys is
accurate.
Trapezoidal belts do not need any particular
maintenance
CALCULATION OF THE
TRANSMISSION 
 

 
NOTATIONS 
D  Pitch diameter of the large
pulley 
mm  P'  Power
absorbed by the machine kWOr nominal power rating of the
Motor Power absorbed by the machine kW Or nominal power rating
of the Motor 
kW  N  Speed of the large
pulley 
t/min  S  Service Factor?/FONT>    d  Pitch diameter of the small
pulley 
mm  Pc  Corrected power  kW  n  Speed of the small
pulley 
t/min  Pb  Uncorrected belt
power 
kW  R  Transmission
ratio 
  Cl  Corrective constant
depending on  The length 
  V  Linear belt speed
 m/s  alpha  AContact angle between the
belt ?BR>and the small pulley 
degr?/FONT>  E'  Centre to centre
(untensioned) 
mm  a  Corrective contact
constant 
  L'p  Belt Pitch length
(Untensioned) 
mm  P  Power transmissible by the
belt 
kW  Lp  Belt Pitch length
(standard) 
mm  x  Number of belts
needed 
kW  E  Centre to centre
(standard) 
mm 





CALCULATIONS FOR
TRANSMISSION 
 
FORMULAS 
EXAMPLES 
Service factor ?see
tableCorrected power : Pc = P’S 
S = 1,25 Pc = 15 kW x 1,25 = 19
kW 
Choice of section : see graph
with respect to the shaft speed and to Pc 
SPA  Transmission ratio n :


Pitch diameters of the
pulleys : d If there are no specific constraints to the transmission
choose the largest possible pulley diameters in order to reduce the
number of grooves 
Chosen diameter : d = 200 mm where D
= 200 x 1,8 = 360 mm or D = 355 mm valeur normalis?la plus
voisine 
Linear speed :
Check in
each section, the recommended linear speed 
 Pitch length of the belt :
: L’p = theoretical belt pitch length
Choose a standard Pitch
length from the chart 
 Calculation of the Centre to
centre distance E :
Or, more simply : :


Pb = Raw belt power as a
function of d, n, R (for a 180?and Lp = Basic length)see Power
tables 
Pb = 10,1 kW  CL = Corrective factor for the
length See CL in the Power tables 
CL = 1,01  a = Corrective factor for the
contact arc in relation to


Calculation of the
transmissible power of the belt P = Pb x Cl x a 
P = 10,1 x 1,01 x 0,98 = 10
kW 
Number of belts :

Rounded to two belts ?2482
SPA, verify that the hubs of the chosen pulleys fit the shaft
diameter required 2 SPA 200  2 SPA
355 

