Snub has more Electric Motor Questions:

Gallery, Projects and General > How do I??

<< < (3/4) > >>

John Hill:
Well just be careful! It doesnt matter if you pop the circuit breaker or even let the smoke out of the motor but we do need you around to come back here and report progress! :beer:

The seperate coil connected to the red wire is the starter coil, that little switch opens when the motor gets up to speed so this coil is only used for starting.

Of course the wires in that diagram are not the same colours as those in your motor! :scratch:

DMIOM:

--- Quote from: snub on June 26, 2010, 01:45:02 AM ---Coils, not resistors? The only knowledge I have of coils are the automotive type, that increase voltage. I was looking at how the yellow and white wires seem to end at ¼ and ¾ of the coil. And the red wire ends at the beginning of another coil. .........
--- End quote ---

well - the diagram you've captured does use the electrical coil symbol (which is a 'curly' line, like an over-extended spring, whereas a resistor is a zig-zag) but in fact they're not coils on their own - they've used that symbology for the windings in the motor - so the wires are tapped in to various points in the motor windings .....

As John says, the separate winding is, I think, the start winding and the symbol above it (can't read it clearly) will be the CFS (centrifugal switch) which disconnects the start winding when the motor gets up to speed.

Dave

Bluechip:
Hi Folks

Can't see it too well either, but ..

It looks like the symbol for a thermal trip to protect the windings ..

Usually looks 'castellated' , like a square wave .. or the top of a castle .... :lol:

Some in here if you want to trawl down far enough, although many manufacturers have their own 'version' of the standard (?) symbol.

http://www.wiringmanual.com/norm006.html

Can't be a centrifugal switch for starting, it would be in series with the capacitor. Or at least in a series 'winding / switch / capacitor' circuit.
Usually doesn't matter which sequence they are in.
Many FHP motors that are not required to start up against any great load, ie fans etc. are capacitor run motors wherby the cap. is permanently in circuit.
Which is almost certainly the case here.

EDIT Sorry, jargon slip ... FHP is 'Fractional Horse Power'

Dave BC

John Hill:

--- Quote from: Bluechip on June 26, 2010, 04:35:52 AM ---

Can't be a centrifugal switch for starting, it would be in series with the capacitor.
--- End quote ---

That would certainly be true if the capacitor was used for starting only but in this diagram the multi-tapped coil is in series with a capacitor which must be always in the circuit.

A starting circuit must produce a phase difference between the run coils and the starter coil, this is often (usually?) done by adding a capacitor to the start coil which has the desired effect of changing the phase of the start coil in relation to the run coils. However, in this case, where the presumed start coil does not have a capacitor but the run coil does there is still a phase difference and hence an effective starting effect.

--- Quote ---Many FHP motors that are not required to start up against any great load, ie fans etc. are capacitor run motors wherby the cap. is permanently in circuit.
Which is almost certainly the case here.
--- End quote ---

Agreed, the capacitor is permamently in the circuit. The differences are that this motor appears to have a seperate starting coil and of course the tapped run coil for the speed steps.

Otherwise that would seem to be an odd place for a motor protection device as even with that component open circuit there would still be power on the tapped coil.

Bluechip:
John

Yes, struck me as being a curious arrangement.

But it does look like a thermal device of some sort. And it would be reasonable to have one.

Pity it ain't on the bench .. would be fairly easy to sort out from the daig..

Dave BC

Navigation

 Message Index

Go to full version