Power Transmission

Motor

Motors are powerful and amazing. Now that I took ECE106 and ECE140, I have a much better understanding to understand how motors work.

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See the Motor Category canvas for the high level tree.

Basics of Motors

Notes from

Motor

An electric motor is a device converting electrical energy into mechanical energy (generally a torque).

This conversion is usually obtained through the generation of a Magnetic Field by means of a Current flowing into one or more coils.

The specific relationship between current and magnetic field generated by a Solenoid is given by:

where (you learned from ECE106), see Magnetic Field

The maximum output torque, and then the maximum efficiency, is obtained when the load angle is 90°

  • The rotation is obtained thanks to the attractive force between two magnetic fields:
  • One field is located on the rotor (the moving part)
  • The second magnetic field is located on the stator (the body of the motor)

Usually

  1. One magnetic field is generated by a permanent magnet (stator)
  2. Other one is generated through an electromagnet (solenoid).

he rotation of the rotor magnetic field (Brot) causes a variation of the magnetic flux in the solenoid.

Consequently an electro-motive force facing the flux variation is generated (Lenz’s law). This effect is named back electro-motive force (aka BEMF) and it is proportional to the motor speed according to the formula:

For example, look at this Brushed DC Motor:

Categories of motors

We can divide Motors divide in 2 main types

  1. AC Motor
  2. DC Motor

AC Motor

  1. Synchronous Motor
  2. Asynchronous Motor (Induction Motor)

DC Motor

  1. Brushed DC Motor
  2. BLDC Motor
  3. Servo Motor

Other Categorization

Go from rotational to linear motion

https://www.portescap.com/en/newsroom/2021/05/convert-rotary-motion-into-linear-motion-with-these-options

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