Help with an electric motor.

DC electric motor speed control help?

• I have a trolling motor that has a selector switch that has 5 forward speeds and 2 reverse speeds. After taking it apart there are 2 wires leading to the switch from the battery and 4 are going to the motor. I'm not very familiar with motors and was wondering if someone could explain: 1) why 4 wires 2) how do they get 5 speeds out of that setup 3) internally how does the switch work

• Answer:

  The reason there are 4 wires is this: The motor has metal "windings" (wires) that are used to spin the rotor of the motor. These windings are divided up. Lets say for example, that the motor has 100 windings, divided into 4 groups of 25 windings each, and each of those 4 groups of 25 windings has it's own wire. If we want full power then we use 100 windings (2 wires) we use the wire that uses all 4 groups. If we want 1/2 power then we use the wire that uses 2 groups of 25 windings. 3/4 will use the wire that uses 3 groups of of 25 winding, etc. This type of motor is usually called a "stepper" motor as it steps up speed using different wires connecting 1 or more groups of windings. Hope this doesn't confuse you but, read it a couple times and you''ll get the hang of it.