Compressors and pump sets usually run for long periods at a defined speed ratio. Pulley selection is therefore driven by motor speed, target shaft speed, belt section, groove count, shaft diameter and the available center distance. A small error in the selected pitch diameter changes the driven speed even when the outside diameter looks close.
For compressor and pump drives, the 12.7 × 10 mm SPA section is commonly reviewed where the existing machine already uses the SPA profile. Pitch diameter and groove count should then be checked with continuous duty, speed ratio, shaft fit and belt wrap in mind.
Typical machine positions
| Machine / position | Selection context |
|---|---|
| Air compressor | Motor-to-compressor drive where ratio, belt capacity and alignment are central. |
| Industrial pump | Motor-to-pump shaft drive with predictable operating speed and service access. |
| Water-treatment pump | Continuous or cyclic pump duty where replacement dimensions and shaft fit need to be repeatable. |
| Refrigeration compressor | Belt-driven compressor auxiliaries where stable tracking and maintenance access matter. |
Selection factors that matter in this application
SPA model references from the application plan
EP-SPA 160-03, EP-SPA 200-03 and EP-SPA 224-04 provide useful starting references for compressor and pump RFQs. The final configuration depends on motor power, driver and driven speeds, center-distance context, shaft diameter and service access.
EP-SPA 160-03
Open the model or matching groove-count series to compare P, O, bush, maximum bore and the lettered dimensions.
EP-SPA 200-03
Open the model or matching groove-count series to compare P, O, bush, maximum bore and the lettered dimensions.
EP-SPA 224-04
Open the model or matching groove-count series to compare P, O, bush, maximum bore and the lettered dimensions.
Installation and maintenance checks
For an existing compressor or pump, send motor rpm, target driven rpm, shaft diameters, center distance if known, belt marking and a photo of the current drive. That information is more useful than a request for “the same pulley”.
| Check | Practical action |
|---|---|
| Pulley alignment | Check axial and angular alignment before final belt tensioning. |
| Belt condition | Inspect the full matched belt set; replace damaged or badly worn belts together when required by the machine maintenance plan. |
| Taper-bush seating | Confirm the bush is fully and evenly seated and that the shaft/key arrangement matches the selected bore. |
| Guard clearance | Verify outside diameter and overall width before closing the machine guard. |
| After commissioning | Recheck tracking, tension and any unusual heat, noise or vibration after the initial run. |
Quote Compressors & Pumps
Send the existing model or measurements, shaft diameter, driver/driven speeds, belt marking, quantity and operating environment to [email protected].