ASEA Motor Wiring

Looks to me like the headphones and coil is just the contactor coil but it is drawn without showing a N connection to the 9 0'clock point.
The coil shown between term 3 and 4 is no doubt the overload trip ciircuit so not drawn correctly.
As drawn it is an induction motor with capacitor start, the capacitor and start coil remain connected during running but only the run coil is sensed for overload.

Perhaps I am mistaking the double lines as a capacitor when in fact it is a centrifugal switch, if so it would still act as an induction motor.

I believe the contactor box is shown in the drawing as lines between 2-3, 3-4, 4-2, these lines are not electrical paths otherwise nothing makes sense.

Emgee

Edited By Emgee on 29/06/2018 14:18:00

Here is a two-page version of the datasheet: **LINK**

http://www.carbonbrush.com/4cr.pdf

But the diagrams are equally incomprehensible

MichaelG.

The following link is primarily for refrigerators, but does indicate the the circle symbol is an overload protector.

http://www.tpub.com/utilities/158.htm

Careful inspection of diagram 14-43 indicates motor terminals as P R and S.

The start relay coil appears to be in parallel with the motor starting winding, rather than in series as suggested earlier.

Edited By AJS on 29/06/2018 15:12:44

AJS

Sorry for being unclear earlier. The relay coil on such devices is always in series with the motor run winding so it is controlled by the run current.

Which is maximum at start up and falls off as the motor climbs up to speed.

Typically the relay will drop out at around 1/2 to 2/3 rds rated speed. Similar to a centrifugal switch. Theoretical advantage of the relay set-up is that the start winding stays in circuit longer when the motor is heavily loaded and working hard to get up to speed. Conversely the start winding drops out faster when lightly loaded so you can get more starts per hour on motors that run up off load. Start winding temperature being the usual limiting factor for single phase motors in start stop work. Practical advantage is no springs, levers and other slightly dubious mechanics to deal with when assembling or disassembling the motor.

Start winding in parallel with relay coil so start current has no effect.

Clive

I think you will find that the circle on the left with the 'headphones' is a klixon overload operated by heat from the motor or from high current passing through the coil. The connection at 9 o,clock is the live connection which goes through the o/l coil to pin 4, when powered up there will be high current drawn by the run winding trying to start the motor and as this goes through the coil between pins 4 and 3 this then operates the relay contacts and puts a live to the start windings, once the motor has started the current will drop and the contacts open taking the live off the start winding. The line crossing along the bottom will be the neutral. This type of relay is used on hermetic compressors on fridges etc where you cannot have a centrifugal switch, but are also useful if the centrifugal switch on a motor is beyond repair just operates by current rather than centrifugal force. But I could be completely wrong as it is 40+ years since I looked at anything like this.

David

The resistance of the coil within the start relay terminals 1 & 3 is low at 0.3ohms and what looks like a capacitor is infact contacts between terminals 2 & 4 as there is no give away capacitance kick on any scale on the ohm meter. As the resistance of the winding between yellow & black is so low I'm inclined to attempt to dismantle it to see how its made. But to do that I am going to have to get bearing puller of sorts to remove the fan from one end.

Dennis

Wonder if the two wires previously dismissed as a thermistor are in fact the start winding, while black and yellow are connected together at one end of the run winding. It does explain Dennis' resistance readings.

Clive's description of how the relay works is convincing but I've not come up with a circuit that uses it and two start capacitors as well. Thought I had a solution but it's wrong. Back to the drawing board...

Dave

To prove the theory that 2 of the wires are from a thermistor, why not put the motor in a warm place or a cold place and see if you get any change in resistance.

David

This looks as if it might work (provided the 12ohm pair are a winding, not a thermistor!):

Note there are two connections on top of the run winding that correspond to yellow and black. If my theory is right, the 15 ohm winding is start and the 12 ohm is run.

Can a motor guru confirm this looks reasonable please.

Dave

I opened up the motor and there are two groups of windings. Please see the enclosed photos:

the connection you can see in the photo is the connection to the yellow wire from two windings. I seperated these and there was 15 ohms between one and the orange wire but a short circuit between the othere wire and the black wire, so i believe the motor is Kaput!

Were do the coloured cables go to. just interested as I am trying to get my head around the resistances in relationship to the coils etc.

David

Enclosed are my findings. There seems to be no protection device connected to black/red. Could this be the start winding?

Hi Dennis,

I think you may be right - you have a shorted winding. But that implies the motor has a tapped coil which I don't understand.

As David asks can you show where the Black wires go. David: this diagram is lifted from Dennis' album. I've circled the peculiar measurement. I was hoping Dennis would find Black and Yellow connected together, and they're not.

I feared the motor might be faulty when Dennis posted the original photo. Someone went to the trouble of disconnecting the relay and capacitors, and that could be explained by fault finding in the past.

My understanding of single phase motors doesn't cover split start windings, so the whole Yellow/Black/Orange thing has me stumped, if that's what they are.

Dave