ABCs of Commercial and Residential Motors

The ABC’s of Commercial and Residential Electric Motors

AC Motor: An alternating current drives AC motors. There are two categories of AC motors – single phase and polyphase (three phase). The power source determines an AC motor's category.

Bearings: Motor bearings allow the motor to turn freely while supporting the shaft, rotor and load (such as a fan blade, blower wheel or pulley). Light to medium loads usually use sleeve bearings. Ball bearings are typically used for heavy loads and/or higher ambient temperatures.

Capacitor: Some motors use capacitors to improve starting torque and electrical efficiency. Capacitors are rated in Microfarads (mf, uf, mfd) and Voltage (V or VAC). When replacing a motor, industry best practice is to replace the capacitor at the same time.

DC Motor: Direct Current (DC) motors have very high torque capabilities. DC motors are sometimes used in conjunction with simple solid state control devices. The devices give programmed acceleration and deceleration over a wide speed range.

Electronically Commutated Motors (ECM): ECMs are the most efficient single-phase motor on the market. ECMs feature an electronic control module and a motor. They do not use capacitors. You can identify an ECM by the application and connections.

Food Processing: Food processing plants are difficult environments for motors. For health and safety reasons, these plants have daily cleaning and sanitizing routines. The corrosive chemicals and high-pressure washdowns used can wear on equipment. LEESON® Extreme Duck® Ultra motors are engineered to seal out all external contaminants. Doing so delivers a high-quality motor that thrives in heavy washdown environments.

Gearmotors: Gearmotors, or geared motors, are gearing and motor packages. Engineered for durability and reliability, both gearing and motor components work together. Operators prefer gearmotors in high-torque, low-speed applications. In these situations, the motor is paired with a gear reducer. You'll see gearmotors in right angle and parallel shaft designs in both AC and DC models.

HVAC/R: HVAC/R motors power residential and light commercial Heating, Ventilation, Air Conditioning, and Refrigeration applications. These applications include:

• Furnaces;
• Air handlers;
• Package units; and
• Refrigeration solutions; including
  • Reach-in and walk-in coolers;
  • Reach-in and walk-in freezers;
  • Refrigeration cases;
  • Vending machines; and
  • Ice machines.

Ingress Protection (IP): IP Markings rate the degree of protection provided by mechanical casings and electrical enclosures against intrusion, dust, accidental contact and water. The International Electrotechnical Commission (ICE) publishes these internationally-recognized ratings. These ratings explain how products can withstand environmental factors found in industrial plants. The food and beverage industry has adopted IP69K certified products because of their use in high temperature cleaning and sanitizing procedures where chemicals cannot penetrate food items. Using IP69K products adds a layer of safety and sanitation to plant operations.

Jogging: Jogging (or inching) is the process of starting a motor with short jabs of power at full voltage. NEMA describes jogging as “the quickly repeated closure of a circuit to start a motor from rest for the purpose of accomplishing small movements of the driven machine.”

Kilowatt: A unit of power equal to 1000 watts and approximately equal to 1.34 horsepower.

Low-Voltage Motor: The IEC considers any motor using less than 1,000 volts to be a low-voltage motor. Low-voltage motors are more widely used than medium-voltage motors and perform in many applications.

Motor Types: Classified by operating characteristics and/or type of power required. The AC induction motor is the most common. There are several kinds of AC induction motors, including, for single-phase operation:

• Shaded pole;
• Permanent split capacitor (PSC);
• Split phase;
• Capacitor start/induction run; and
• Capacitor start/capacitor run.

Larger applications use polyphase (or three-phase) motors. Common DC motors are gearmotors and brake motors.

NEMA® (National Electrical Manufacturers Association):A nonprofit trade organization. Manufacturers of electrical apparatus and supplies in the United States support the organization. NEMA standards ease misunderstanding and help buyers select the proper products. Standards cover:

• Frame sizes and dimensions;
• Horsepower ratings;
• Service factors;
• Temperature rises; and
• Various performance characteristics.

Overload: Motor overload occurs when a motor is under excessive load. When a motor overloads, you may notice overheating or insufficient torque. Overload protection can help protect the motor and allow it to perform as expected.

Permanent Magnet (PMAC) Motors: PMAC motors (or synchronous AC motors) are like standard induction AC motors. PMAC motors have permanent magnets attached to their rotors. PMAC motors are known to be more efficient than standard induction motors.

Quick Reference Motor Guide: The Quick Reference Motor Guide will help you determine the best products based on motor dimensions.

RPM (Revolutions Per Minute): RPM measures how fast an electric motor is operating at a given time.

Service Factor: The a measure of continuous overload capacity at which a motor can operate without overload or damage. Service factor depends on design parameters like rated voltage, frequency and ambient temperature being within norms.

Torque: The turning effort or force applied to a shaft. Usually expressed in inch-pounds or inch-ounces for fractional and sub-fractional HP motors.

Underwriters Laboratories (UL) Listing: Independent United States testing organization. UL sets safety standards for motors and other electrical equipment.

Variable Speed Motors: Variable speed motors have a variable frequency drive (VFD). The drive controls motor speed and torque. Adding a VFD to a three-phase induction motor permits the speed of the motor to be adjusted based on a motor’s load or application requirement. Doing so saves energy. The VFD provides voltage and frequency in a precise method as the motor starts. This eliminates energy waste and provides a soft start to the application. In turn, the motor can see an increased lifespan for and an economical method for speed control.

Washdown Duty: Washdown duty motors can stand up to high-pressure and high temperature washdowns at close range. They are certified with the IP69 rating. This is the highest certification available for protection against solids and liquids.

XP- Explosion Proof: Explosion proof motors are required for Division I hazardous locations. These locations involve gases, liquids, or vapors including Class I Group D, Class I Groups C & D. Applications include:

• Petroleum and chemical plants or pipelines;
• Gasoline pumps; and
• Natural gas compressors.

Y Suffix: A motor nameplate letter suffix that sometimes causes some confusion is the “Y”. This indicates that the motor has special mounting dimensions. The manufacturer must provide these dimensions.

Zillion: The number of electric motors in use around the world. You can find electric motors in (or used in the processing of) nearly every product we use or touch.