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Things To Know When Choosing an Electric Motor

Electric motors are the quiet workhorses of industry, transforming electrical energy into mechanical power for everything, from small fans to conveyor belts to huge wind turbines. Selecting the right motor for your application can feel overwhelming, but here’s our clear, helpful overview to guide you.

What is an Electric Motor?

Any machine that moves or rotates probably relies on an electric motor. Small motors power fans, pumps, and conveyors; medium motors drive cranes and sawmills; and very large motors run crushers or wind turbines.

How to Choose an Electric Motor

If you’re replacing an existing motor, start with the motor’s identification plate, or nameplate - that’s the metal tag on the motor body. It’s an invaluable source of important information, as it lists key specifications, such as:

  • Voltage and current (AC or DC)
  • Phase (single phase or three phase)
  • Material (cast iron vs. cast aluminium)
  • Speed rating
  • Power output
  • Mounting style

Reading a TEC Part Code or SKU

This also tell a story. For example: 3.043TECAB35-IE3

  • 3 = kilowatts (kW)
  • 4 = number of poles
  • 3 = phase
  • TECA = aluminium housing
  • B35 = mounting style
  • IE3 = efficiency rating

The rated output of an electric motor is usually given in kilowatts (kW). On older nameplates you might still see horsepower (hp) instead. To convert, remember this simple rule: 1 hp ≈ 0.75 kW.

  • Efficiency class

    Higher is better! Ranging from IE1 to IE4, IE1 (standard), IE2 (high), IE3 (premium), IE4 = (super premium)

  • Duty Cycle

    IEC (the International Electrotechnical Commission) ratings describe how long a motor can run under load, from S1 to S10. Tec Motors are S1 continuous running duty.

  • IP rating

    Indicates protection from dust and water. TEC motors are IP55 as standard. To find out more about IP ratings, have a look at our Help & Advice page What Does the IP Rating Mean?

Key Questions to Ask

If you’re buying a motor for a job, we need to think about:

  • Purpose: What will the motor drive?
  • Environment: Indoors, outdoors, dusty, or damp?
  • Power needs: How much torque is needed?
  • RPM: What speed is needed?

A motor must deliver enough torque at the right speed to keep things moving.

Motor speed can be expressed in RPM or by the number of poles:

  • 2 poles ≈ 3000 RPM (synchronous)
  • 4 poles ≈ 1500 RPM
  • 6 poles ≈ 1000 RPM
  • 8 poles ≈ 750 RPM

Real world speeds are slightly lower due to slip. WE can use this formula to calculate: Rated RPM = (120 × frequency) ÷ number of poles

Mounting Options

Choosing the correct mounting ensures safe operation and long motor life. We offer several common mounting options:

  • B3 Foot Mounted: the motor is flat on the ground, with the shaft horizontal and attached to the base. Common with pulleys or couplings.
  • B35 Foot & Flange Mounted: an outer flange with a diameter larger than that of the motor housing. Common in hydraulic or geared applications.
  • B34 Foot & Face Mounted: an inner flange with a diameter smaller than that of the motor housing. Common with pumps and geared motors.

Other mounting options are available. Please contact us to discuss your needs.

Frame Size Matters

Our TEC motors adhere to IEC Standards; dimensions are directly related to the Shaft Height, or Frame Size of the motor. 

Frame size = distance in mm from the motor base to the shaft centre. Example: A 160 frame measures 160mm.

Material Choices

Our TEC motors coming a choice of Aluminium, which is lightweight and easy to install, or Cast Iron, which is heavier but stronger and more rugged for tough environments.

All TEC Electric Motors are:

  • Low voltage
  • IC411 TEFC (totally enclosed, fan cooled) as standard
  • Rated IP55 as standard
  • Rated S1 for duty
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What About an Inverter?

An inverter converts direct current (DC) to alternating current (AC) and lets you fine tune the output frequency for precise speed control - ideal for variable speed applications. TEC three phase motors pair perfectly with compatible inverters. We stock a range of IP20 rated inverters, from 0.37kW to 37KW, and IP66 rated, switched and unswitched. 

These IP66 rated inverters are engineered for outdoor use and direct machine mounting, and offer complete protection against dust, contaminants, and high-pressure washdowns. Built from tough polycarbonate plastics, specifically chosen to resist UV exposure, greases, oils, and acids, these drives remain impact-resistant even at -20 °C. With a sealed enclosure and corrosion resistant heatsink, they inverter is ideal for hygiene critical environments such as food and beverage processing. To see our full range of inverters

Click here

Why Buy TEC Electric Motors From Us?

We offer a wide range of TEC’s reliable single phase and three phase motors, along with inverters, all backed by expert support. Whether you need a compact pump motor or a heavy duty industrial drive, you’ll find:

Have questions? Contact our sales team - we’re happy to help you choose the perfect electric motor for your project.

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Keywords: Motors for compressors, motors for pumps