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Here is a diagram showing the main information contained within a motor plate:

Motor plate basics

Main Elements of a Motor Plate

You may know some of this information already but we hope it may come in handy when you are trying to explain to us what kind of motor you need but don’t have the facilities to photograph it and get it sent across quickly to us.
  • 3 - This motor is a 3 phase motor and can only be used with a standard 3 phase supply on an inverter*.
  • Kilowatt of the motor which in our case was the 0.37 - There are different Powers on Motors ranging from small motors in arcade machines right up to large motors which keep whole power plants and factories running.
  • Frame sizes – these are aligned to the KW of a motor, as you couldn’t get the power out of something that fits in an arcade machine to run a whole factory.
  • Bearing sizes - Only shown on some plates, these are useful for us to identify which bearing is needed from our large stock without stripping the motor down.
  • Amps - The maximum amount of amps the motor should be pulling will be shown on all motor plates, this is very useful if you feel the motor is running warm or is struggling to start up or cope with the task it is being used for. The amps can be checked with a standard ammeter, if our customers do not have the tools to do this one of our sales engineers can pop to your site and do these checks! With their knowledge they may also be able to determine your best next step for you.
  • RPM of a motor - This is also something that should be on every motor plate, you can check the motor RPM with a taco. If a motor is running slow it can be a number of things wrong, all of which we can sort out at Grantham Electrical.
  • Voltages - Some motors have varying voltages on the plates. When there are 2 different voltages on a motor plate, they are usually 230v-400v or 400v-690v. This is due to the popularity of *Inverters. Inverters are a good way of controlling many different parameters which include the speed of your motor, also how fast your motor gets up to speed and slows down.
  • Cycles - A motor can run at 50 Hz (standard for the UK) and 60 Hz (standard for USA). Changing the Hz is how the inverter controls the speed of your motor.


Mountings on standard motors