Precision Variable Speed Pulleys (VPSR)

Precision Variable Speed Pulleys (VPSR) provide all the proven benefits of the well established VPS (Variable Speed Pulleys) Series and include the following features to provide quiet running operation:

Close tolerance on round shaft
Molded keyway
Precisely ground and polished shafts
Infinite speed range - within pulley's ratio limits
All variable speed pulleys are spring-loaded and color-coded to indicate spring pressure

Standard sizes and types, detailed dimensions and spring pressures are listed below.

Precision Variable Speed Pulleys (VPS) Engineering Specifications
Model	Belt	Speed Ratio	HP Rating @ 1800 RPM	Approx. Pitch Dia.	Standard Bores						Weight
Model	Belt	Speed Ratio	HP Rating @ 1800 RPM	Approx. Pitch Dia.	1/4	5/16	3/8	1/2	5/8	3/4	Weight
VPSR-10	1/4" V	Up to 2.25:1	1/12	23/32" Min 1-3/4" Max	•	•	•				Under 3 oz.
VPSR-15	3/8" V	Up to 2.45:1	1/4	1-3/8" Min 2-3/4" Max			•	•			5 oz.
VPSR-20	1/2" V	Up to 2.8:1	1/2	1-7/16" Min 3-1/2" Max				•	•		8 oz.
VPSR-43	1/2" V	Up to 2.8:1	3/4	1-21/32" Min 4.0" Max					•	•	1 lb. 11 oz.
VPSR-50	5/8" V	Up to 2.8:1	1.0	1-5/8" Min 4-3/4" Max					•	•	1 lb. 14 oz.

Standard Tolerances for Bore Sizes, Keyways and Setscrews

Precision Variable Speed Pulley dimensions

Precision Variable Speed Pulleys (VPS) Pulley Dimensions
Model	A	B	C1 Open	C2 Closed	D Dia.	Standard Bores
Model	A	B	C1 Open	C2 Closed	D Dia.	1/4	5/16	3/8	1/2	5/8	3/4
VPSR-10	2-1/8	1/2	1/2	1/4	1-7/8	•	•	•
VPSR-15	2-5/8	9/16	3/4	7/16	2-7/8			•	•
VPSR-20	3	5/8	7/8	1/2	3-1/2				•	•
VPSR-43	4-1/4	25/32	1	1/2	4-1/4					•	•
VPSR-50	4-1/4	25/32	1-1/4	5/8	5					•	•

WARNING: All open belt drives must be adequately guarded for personal safety during operation.

Precision Variable Speed Pulleys (VPS) Spring Pressures
Model	Spring Strength	Color Code	LBS. COMPRESSION IN SPRING
Model	Spring Strength	Color Code	As Pulley Starts to Open	Pulley Fully Open
VPSR-10	Medium Heavy	White Blue	6 8	9 11
VPSR-15	Medium Heavy	White Blue	14 17-1/2	18-1/2 22
VPSR-20	Medium Heavy	White Blue	18 22	23 27-1/2
VPSR-43	Medium	White	33 50	40 64
VPSR-50	Heavy	Blue	50 66	64 82

VPS Pulleys are shipped with the blue, heavy strength spring unless another strength spring is requested.

Pulleys: Timing Belt Pulleys, 3mm HTD, 5mm HTD, 8mm HTD, XL Series, L Series
Variable Speed Pulleys, Round Belt Pulleys, Poly V Pulleys, Custom Pulleys

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