Need help with the circuit of an AC motor and the PLC

[keithkyll]

Resistance rises as the filament (or heater element) gets hotter. This would be a problem with a load. I assume the motor will be run unloaded.
["rope start" the motor]
You (and Ron) are thinking Split Phase Induction Motor. His motor looks more like a Permanent Split-Capacitor (PSC). Go to the bottom of the page of this Wikipedia link .
I don't disagree that the resistor idea might not work very well, but his instructor has approved it. We'll go with it for now, unless he switches to the Triac controllers.
Either way, we'll all learn something.

 

[milldrone]

keithkyll,

Actually I was deriving my logic from 3 phase motor current (600% at locked rotor) and thinking a permanent split motor would be simular in current characteristics.

Either way, we'll all learn something.

You bet!:nodi:

 

[Tripper]

I know this maybe off point a little, but in this country you cant touch low voltage without a licence.

I cannot see any reason why the instructor/superviser/boss cant teach the same using extra low voltage.

I think we have missed two vital items:

An earth on the motor (in his schematic)

and a RCD (saftey switch at the start of the cct unless his house already has one)

 

[Lancie1]

So, Sogoatticus, did it work? What were your results? What did you actually use for speed control?

 

[sogoatticus]

So, Sogoatticus, did it work? What were your results? What did you actually use for speed control?

unfortunately it did not work..those wirewounds only limit the torque i guess (just hold it with my hands and feel it). tthe speed still remain the same even i change to different wirewounds. im still study and searching on the web. A bit scary to ask here bcause my knowledge limited about this. hope to find a simple circuit to make the motor run at 2-3 speeds

 

[Lancie1]

Sogoatticus,

I suggest that you try very hard to determine which type of AC 1-phase motor that you have. Wiikipedia might help. Look under "Single Phase AC Induction Motor". Once you know which type your motor is, you can then search for speed control methods for that type of motor.

http://en.wikipedia.org/wiki/AC_motor