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4QD - Electric Motor Control

Helping mechanics get the electrics working



We manufacture DC motor speed controllers for electric motors that are tough, reliable, and easy to use

Welcome to 4QD – Electric Motor Control

YouTube video

We have a range of DC motor speed controllers and accessories for battery powered electric motors that are designed and built in the UK.

Our passion is getting stuff working – industrial machines as well as hobbyist. We love helping mechanics get the electrics working, and can provide electric motor speed control solutions for almost anything with a battery and a DC electric motor, to see the sort of thing we’ve done have a look here,  or just browse around the site, all of the pictures throughout this site are using our controllers.

  • Our motor controller range covers 30 to 360 amps, 12 to 84 volts, and can be used in a wide variety of applications that use permanent magnet electric motors.
  • Our new Pro-160 and Pro-360 are the only controllers on the market with a remotely mountable display showing voltage, current, and temperature.
  • All our products are easy to wire up and adjust.
  • Our controllers (aka motor drivers] are reliable, many are still going strong after 25+ years.
  • We will ship to any country.
  • We have a range of additional heatsinks available, if you need a high power, water cooled PWM controller ours are some of the best value on the market.
  • We have an extensive knowledge base with lots of technical support, manuals, wiring diagrams and background information on a wide range of motor control topics e.g. what is PWM? and how is H-bridge switching done? If you prefer videos, then we’ve got a selection on installation, troubleshooting, and general interest here.
  • We love talking to customers about their applications and would like to hear from you if you have a special project or ideas for new products.
  • We can help with designing wiring looms.
  • We can develop bespoke control products and software.
  • We have full control over production and do not rely on stretched supply lines.

For a diagram of a basic installation click here.

For help choosing a controller click here.

Come and have a look… our controllers are here, and our accessories are here.

Or just pick up the phone, we’re on 01487 450520 and are always happy to chat about your project.