I have been playing around with a couple of little 12v dc turntable motors and am curious as to what internal wiring they have for speed control.
Two of the wires are simply + and - which I presume feed the armature via the brushes , however the other two are a bit of a mystery to me. If they are left open circuit the motor runs very fast and if they are shorted together the motor will not run. Adding a variable resister between them varies and adjusts the speed. Please explain for my simple brain what is happening inside the motor.
Confused
Graham😕😕
Two of the wires are simply + and - which I presume feed the armature via the brushes , however the other two are a bit of a mystery to me. If they are left open circuit the motor runs very fast and if they are shorted together the motor will not run. Adding a variable resister between them varies and adjusts the speed. Please explain for my simple brain what is happening inside the motor.
Confused
Graham😕😕
they'll be pulse sense wires. shorting them you have created a back emf that stops the rotor turning past the sense coil. probably.
cheers rex
cheers rex
A lot of very cheap dc servo motors were used in budget belt drive TT, and in fact those two extra wires, were probably for, you guessed it, a pot. (Or two pots and a switch)
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