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Pump Products carries an extensive selection of electric motors for motor driven pumps of most sizes and styles. We currently offer WEG’s most popular General Purpose and Definite Purpose AC models including Auger Drive Motors, Compressor Duty Motors, Cooling Tower Motors, Crusher Duty Motors, Explosion Proof Motors, Farm Duty Motors, Saw Arbor Motors, Petrochem Motors, Jet Pump Motors, Oil Well Pump Motors, P-Base Motors, Pool and Spa Pump Motors and many other models.

Electric motors operate at peak power and efficiency when fully loaded, so choose a motor that’s appropriately sized and rated. Motors are rated by the output power they can produce over a given time period without overheating. These ratings can usually be found on the motor nameplate.

Motors are also manufactured in a range of duty cycles: Those requiring constant torque and those in which torque demand changes gradually or abruptly.

For pumps requiring constant motor driven load, check the nameplate, or determine the torque required to turn the load. Choose a motor for which the load is 75 to 100% of the motor’s rated capacity. When the load is steady with a long duty cycle it’s safe to load the motor close to its full load capacity (up to 95%). This will optimize motor efficiency and minimize operational cost.

For pumps requiring variable motor driven load, determine the entire load range over which the pump will operate. Make note of peak load demands and duration. Use peak loads to calculate motor size because the motor must be able to drive through the peak demands without overheating.

Inertia is a load that must be overcome. The process of overcoming high inertia-loads at startup generates extreme heat. The National Electrical Manufacturers Association, or NEMA, has designated four motor types identified by the letters A, B, C, and D.

Design A Motors work well with more constant torque applications and low inertia. Type A motors have medium to high starting currents that create rapid heat buildup.

Design B Motors are economical, general-purpose units. Because starting torque is low, they are not suitable for high-inertia loads.

Design C Motors are suited for equipment with low starting current such as positive displacement pumps. They are characterized by low starting current, high locked rotor torque and normal breakdown torque.

Design D Motors are designed to handle very high-inertia loads with low starting currents, minimizing heat buildup in the motor during start. Lower starting current means type D motors slip 5 to 13% compared to the less than 5% slippage for types A through C.

Contact a member of our expert for more information on electric motor sizing and selection at 1-800-429-0800 or visit our website at www.pumpproducts.com. You can rely on Pump Products to deliver WEG products to you at the lowest prices on the internet. Make us your go-to supplier of WEG motors and accessories.