High slip motors, or Design D motors, power cycling load, oil well jacks, low-speed punch presses, hoists, and more. A 1200 rpm motor works best for oil well pumping units. Why? A motor has a high slip of five to eight percent and a high starting torque. Manufacturers have developed several types of electric motors high slip designs for these specifications.
Slip Basics for Electric Motors
What do we mean by “slip”? Manufacturers have produced thousands of types of electric motors. Motors operate a synchronous, or fixed, speed. The number of poles and driving frequency determines the synchronous speed. Induction motors, however, have a speed that falls below the fixed speed. Torque drops off. The motor ends up producing less torque per amps.
A high slip motor allows the torque to increase torque per amps even as the motor moves from fixed speed to the locked rotor state. Standard NEMA Design A, B, or C motors operate at one to five percent slip. A NEMA D motor has a high slip of five to thirteen percent.
Why Slip Matters
As soon as the motor of a NEMA A, B, or C motor changes slip, it gives high torque. However, not all applications benefit from this. Pump jacks can have a severe fluid problem, mechanical failure, and damage to valves.
A NEMA D motor has a slip that changes without too much torque. This results in much less damage. A high slip motor has a “sloppy torque” ideal for pump jacks and similar applications like sucker rod pumps. Most Design D motors have a slip of five to eight percent.
Call the Electric Motor Experts
When you need a high-quality electric motor or motor repair, call the seasoned team at LN Electric Motors. We provide a wide range of services for AC and DC motors, belted fan motors, pumps, and more. Our trained professionals can help you with any motor issue from sewage pumps to rewinding your motor.
No matter your unique motor needs, call LN Electric Motors today. Our friendly staff will be happy to help answer your questions. We offer a wide variety of helpful services and products. Contact us today.