Castair Open Drip Proof Motor — 2 HP, 115/230V, Single Phase, Frame 56, 3450 RPM
This is the replacement motor for Castair belt-drive air compressors running on single-phase power. The 2 HP rating and 3450 RPM speed pair with the NEMA 56 frame — a standard footprint that drops into most Castair single-phase compressor setups without modification. If you are replacing a burned-out motor or upgrading a compressor that came with a weaker drive, this is the part number to order.
The dual-voltage wiring (115V/230V) is practical for real shop situations. Smaller shops often run 115V circuits at the compressor location. Larger shops, or those looking to reduce amp draw on a loaded circuit, can wire this motor for 230V. Same motor, different connection — just follow the wiring diagram on the nameplate.
Motor Specifications
- Horsepower: 2 HP
- Voltage: 115/230V dual voltage
- Phase: Single phase (1Ph)
- Frame: NEMA 56
- RPM: 3450 (high speed — suited for belt-drive compressor pumps)
- Enclosure Type: Open Drip Proof (ODP)
- Part Number: 2-56-1H
Open Drip Proof Enclosure — What It Means for Shop Use
ODP motors are designed for clean, dry indoor environments. The enclosure allows airflow for cooling while preventing drips falling at up to a 15-degree angle from entering the motor. This is appropriate for most shop floors where the motor is not exposed to wash-down, heavy dust, or outdoor elements.
- Ventilated design: Cooling air circulates through the motor for better heat dissipation under sustained load
- Not sealed: Keep away from direct water spray, heavy sawdust, or metalworking chip environments — use TEFC (totally enclosed fan cooled) if your environment has those conditions
- Suited for: Standard compressor rooms, enclosed compressor cabinets with filtered airflow, and typical automotive or light industrial environments
NEMA 56 Frame — Fit and Mounting
The NEMA 56 frame defines the footprint: shaft height, bolt hole spacing, shaft diameter, and shaft length. When swapping a motor — if the frame matches, the mount bolts up and the shaft lines up with the existing belt drive or pump coupling.
- Frame designation: 56 (NEMA standard)
- Shaft: Standard NEMA 56 shaft dimensions — verify against your existing motor for a direct swap
- Mounting: Rigid base mount — requires motor mount plate or base bracket appropriate for your compressor model
- Belt-drive compatible: The 3450 RPM output shaft accepts standard V-belt sheaves for compressor pump drives
3450 RPM — Why It Matters for Your Pump
A 3450 RPM motor is the high-speed option — used on smaller displacement pumps designed to run fast. This is different from a 1725 RPM motor, which is used on larger pumps that need slower shaft speed. If you are replacing an existing motor, confirm the original was rated at 3450 RPM before ordering. Putting a 1725 RPM motor on a pump sized for 3450 RPM will cut your CFM output roughly in half.
- High-speed motor: 3450 RPM nominal full-load speed
- Use with: Castair compressor pumps and belt-drive assemblies rated for 3450 RPM motor input
- Do not use as a drop-in replacement for: 1725 RPM motor applications without verifying pump compatibility
When Does a Shop Need This Motor?
- Motor failure on an existing Castair compressor: This is the correct OEM replacement for Castair belt-drive units built around the NEMA 56 frame at 3450 RPM
- Voltage upgrade: If you are rewiring a compressor circuit from 115V to 230V to reduce amp draw, this motor supports both without a parts change
- Rebuilding a used compressor: Picked up a used Castair pump assembly without a motor? A 2HP/56 frame/3450 RPM motor is a common spec for small single-phase belt-drive setups
- Replacing an undersized motor: If a previous owner installed a weaker motor and the compressor runs hot or recovers slowly, the correct 2HP replacement restores designed performance
Technical Specifications
- SKU: 2-56-1H
- Manufacturer: Cast Air (Castair)
- Horsepower: 2 HP
- Voltage: 115/230V (dual voltage, single phase)
- Phase: 1 Phase
- Frame: NEMA 56
- Speed: 3450 RPM
- Enclosure: Open Drip Proof (ODP)
- Application: Belt-drive air compressor replacement motor
Note: Manufacturer product page data was not available at time of writing. Specifications are derived from the product name and part number. Contact us to confirm fit for your specific Castair compressor model before ordering.
Why Buy From Air Compressor Factory Direct?
We have specialized in industrial air compressor equipment since 2016. When you call us, you reach someone who understands compressor motor frames, voltage wiring, and replacement part compatibility — not a general parts counter. We stock Castair components and can confirm the right motor for your specific compressor model before you order.
- Free shipping on qualifying orders
- Free tech support: Call 866-217-0063 with your compressor model number and we will confirm fit
- Full manufacturer warranty on all motors
- Honest guidance: If this motor is not the right fit for your compressor, we will tell you what is
Call 866-217-0063 for quick answers and help!
