Leeson

The most critical step is to find the nameplate on your old motor. This plate contains all the essential information needed for a replacement. You must record the following data:

• HP (Horsepower)
• RPM (Revolutions Per Minute)
• Voltage
• Frame Size (e.g., 56C, 145T)
• Enclosure Type (e.g., ODP, TEFC)

Providing an authorized distributor with all this information will ensure a fast and accurate match.

The enclosure protects the motor’s internal components and is based on the operating environment:

• ODP (Open Drip-Proof): Vents allow air in for cooling, but prevent drops of liquid from falling into the motor within a $15^\circ$ angle from vertical. Best for clean, dry, and well-ventilated indoor areas.
• TEFC (Totally Enclosed Fan Cooled): Tightly enclosed to prevent the free exchange of air, but not airtight. It has an external fan to blow air over the frame for cooling. Best for dirty, dusty, or mildly damp environments.
• TENV (Totally Enclosed Non-Ventilated): Tightly enclosed, but relies on the motor’s surface convection for cooling (no external fan). Best for areas with extreme dirt or dampness where a cooling fan might clog.

Leeson offers thousands of stock and custom options, but the most common types are:

• General Purpose: Used for standard industrial applications like pumps, fans, compressors, and conveyors in relatively clean environments.
• Washdown Duty (e.g., Washguard® or Extreme Duck™ Ultra): Designed for food processing, beverage, and chemical environments that require frequent, high-pressure cleaning.
• Farm/Agricultural Duty: Built with extra-high starting torque and sealed components to withstand outdoor and rugged conditions, like augers and crop dryers.
• DC Motors: Used when precise speed control and high starting torque are required, often with a Variable Speed Drive (SCR rated).

Operating at the nameplate voltage is crucial for long motor life.

• Under-voltage (too low): The motor attempts to maintain its rated horsepower by drawing more current, which leads to overheating and premature failure.
• Over-voltage (too high): Can reduce efficiency and shorten insulation life. NEMA standards typically allow for a $\pm 10\%$ voltage variation, but optimum life is achieved at the rated value.

Many smaller motors (10 HP and below) are permanently lubricated from the factory and should not require re-lubrication. For motors with grease fittings, lubrication frequency depends on the motor’s frame size, HP, and hours of operation. Always check the motor’s nameplate or Instruction & Operation Manual (IOM) for the specific grease type and schedule, as excessive or incorrect lubrication can cause bearing failure.

For initial installation, the most likely cause is miswiring. Re-check the wiring diagram provided with the motor for both the power and direction connections. If the motor had been running previously, common causes include:

• Low Voltage: Check the power supply at the motor terminals.
• Defective Capacitor (for single-phase motors).
• Increased Load: The equipment being driven may be jammed or too heavy for the motor’s rating.