H

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
SPZ	> 80	38	8,00	12,00	9,9	9	2,00
SPA	< 118	34	10,00	15,00	12,7	11	2,75
SPA	> 118	38	10,00	15,00	12,9	11	2,75
SPB	< 190	34	12,50	19,00	16,1	14	3,50
SPB	> 190	38	12,50	19,00	16,4	14	3,50
SPC	< 315	34	17,00	25,50	21,9	19	4,80
SPC	> 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 rsing	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
Rsals 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