Motor short course.
Posted: Fri Jan 17, 2014 6:45 pm
holsgo wrote:The plot continues to thicken then...so I guess dual voltage means 110 and 220 motor (like the one on this machine) and a 110 only is single voltage (like my old south bend lathe motor we worked on some time back).
Jpg, you could do up a write up of some of this and make some of us very happy. Like with pics of samples, sample wiring diagrams etc. I've trolled youtube looking for some motor stuff, and found some great things but nothing that comes close to you explaining it.
One guy explained 3 phase and single phase and it was fantastic. I need to find it.
3 phase is 'easier' to reverse, but dual voltage would get messy.(not practical since if ya got 3 phase, different voltages are not useful) The motors are simpler although have half again as many run windings but no start windings(IIUC).
The single phase motors are actually fairly simple(at least those we have been discussing).
They have run coils, start coils and a start circuit. Typically the start circuit uses a capacitor that is only 'in the circuit' at startup. Its sole function is to establish the run direction. Once the motor is running either a centrifugal switch opens the circuit or the induced emf from the start winding picks a relay with contacts that also open the circuit. These contacts stay open until the motor coasts down.