Castair Replacement Industrial V-Belt — Section B, 47" Length (3-B47)
The Castair 3-B47 is a Section B industrial V-belt at 47 inches outside circumference. Section B belts are wider and deeper than Section A — 21/32" top width versus 1/2" — which means higher torque capacity. They are used on larger or more demanding drive configurations where the power transfer requirement exceeds what a Section A belt can handle reliably. If your Castair compressor calls for a B-section belt, you cannot substitute a Section A even if the length is close.
Manufacturer page data was not available for this listing. Call 866-217-0063 to confirm this is the correct belt for your compressor.
Section B Belt Details
Cross-Section Comparison: A vs. B
- Section A: 1/2" top width, 5/16" depth — lighter drives, smaller motors
- Section B: 21/32" top width, 13/32" depth — heavier drives, larger motors, higher torque
- The pulley groove must match the belt section — B-section pulleys have a wider, deeper groove than A-section
- Do not run a Section A belt in a Section B pulley or vice versa
3-B47 Specifications
- Part Number: 3-B47
- Belt Section: B (21/32" top width, 13/32" depth)
- Outside Circumference: 47 inches
- Application: Castair compressors requiring Section B, 47" belt
- Price: $13.86
Belt Maintenance Guidelines
- Inspect belt condition and tension every 250 hours on heavy-duty or continuous-duty compressors
- Replace belts showing cracks, glazing, fraying, or cord exposure
- Always check pulley alignment when replacing a belt — misalignment is the number one cause of premature belt failure
- On multi-belt drives, always replace all belts as a set — mixing old and new belts causes uneven load distribution
Related Castair Section B Belt Sizes
- 3-B47 — 47" (this belt)
- 3-B52 — 52"
- 3-B112 — 112"
Technical Specifications
- Part Number: 3-B47
- Belt Section: B
- Outside Circumference: 47 inches
- Top Width: 21/32" (17mm nominal)
- Thickness: 13/32" (11mm nominal)
- Price: $13.86
Why Buy From OEM Diagnostic Tools?
- Specialist since 2016 in air compressor components
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