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 11.12 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. Itís 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
DPitch diameter of the large pulley mmP'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
NSpeed of the large pulley t/minSService Factor?/FONT>-
dPitch diameter of the small pulley mmPcCorrected powerkW
nSpeed of the small pulley t/minPbUncorrected belt power kW
RTransmission ratio -ClCorrective constant depending on -
The length
-
VLinear belt speed m/salphaAContact angle between the belt ?BR>and the small pulley degr?/FONT>
E'Centre to centre (untensioned) mmaCorrective contact constant -
L'pBelt Pitch length (Untensioned) mmPPower transmissible by the belt kW
LpBelt Pitch length (standard) mmxNumber of belts needed kW
ECentre to centre (standard) mm


 

CALCULATIONS FOR TRANSMISSION
FORMULAS EXAMPLES
Service factor ?see tableCorrected power : Pc = PíS 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 : :
Líp = 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