ASEA Motor Wiring

Hello,

Im looking for some help in wiring up an ASEA motor for my Myford ML7 lathe.

looking at the phots this is how the motor came to me. The little black box with 3 terminals I believe is an electronic start relay but I could be wrong. It is labelled 4CR-6-678 and it is made in America. The two blue & Brown wires at the top of one picture come from 2 Capacitors and from inside the motor come a pair od wires plus another group of 3 wires. there is no physical connection the two sets of cables whem using an ohm meter.

I hope someone can help me as ABB the people who took over ASEA cannot!

Thanks,

Dennis

Here are the pictures

From what I can see of the motor plate it appears to be a single phase motor as it appears to be a 220V 3.9A device though a search on the motor type number might help. A better picture of the motor plate would help Dennis

Nige

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Putting that reference in Google search offers this : **LINK**

https://www.sensata.com/sites/default/files/media/documents/2018-05-31/ourproducts_4CR_datasheet.pdf

MichaelG.

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Dontcha just love Klixon as a name for a relay 

Edited By Michael Gilligan on 26/06/2018 18:23:27

Thank you gents for the information so far. Now I know I have an electronic start realy with a service sheet showing its layout. Looking more closely at the two cables coming from inside the motor (windings I expect) the two wires there is 12ohms between them with no connection to the other group or the frame/body.

The 3 wire group. Lets say the wire colours are Black, Orange & Yellow.

Yellow to Black = 8ohms,

Yellow to Orange = 15 ohms

Orange to Black = 15 ohms.

I believe these to be the main windings but what does thes the 2 wire group do?

The two capacitors are 60 microfarad 330v and 20 microfarad 400v.

Finally here is a better picture of the information label/

Hope this helps..... Many thanks again.

I would guess that the 2 wire group is a thermister or thermostat for overheat detection

Some possibly useful info here :

**LINK**

Thanks nige for that but I have already been in contact with ABB and they cannot help as they no longer make single phase motors!

I guess you're not getting many answers Dennis because your motor is a shade mysterious, requiring more than average detective work to suss out what the various connections are. To be certain someone would have to recognise the motor and know how it was connected. Might not be luck - it's about 50 years old, was made by a defunct company, and may not have been common in the UK.

Back to the clues: we know it's single-phase, has two capacitors, and an external switch (rather than a centrifugal switch). You also said :

The 3 wire group. Lets say the wire colours are Black, Orange & Yellow.

Yellow to Black = 8ohms,

Yellow to Orange = 15 ohms

Orange to Black = 15 ohms.

That's a bit of a worry because I don't understand how those three measurements add up. With 3 connections, I'd expect one of the 'Orange' measurements to be 8 + 15 = 23 ohms. Could you have made a mistake?

Assuming you did, this is the circuit I'd try. WARNING! I am not a motor expert, but I do understand how to wire up and test a motor like this safely. While I hope I've made an intelligent guess, I am guessing. Also, in my own workshop I'd be happy to risk damaging the motor. I might have start and run windings the wrong way round, and/or the large and small capacitors.

If you're brave, have a go. You might prefer to wait to see if this post wakes up an expert; there are people on the forum with far more experience of motors than I.

I suggest:

• The odd pair of wires are connected to a temperature sensor used to detect when the motor is overheated. They can be ignored.
• The start winding is the lower resistance winding. (Yellow Black - 8 ohms)
• The run winding is the higher resistance winding. (Yellow Orange - 15 ohms*)
• The start capacitor is the 60uF
• The run capacitor is the 20uF

* Note uncertainty - this could be wrong because you said Orange Black was also 15 ohms making the wiring ambiguous I'd be much happier if Orange-Black was 23 ohms.

Hope this helps!

Dave

i'm sure you will have looked but usually theres a wiring diagram in the lid of the terminal box cast or printed

Hello Dave, Thanks for this as I believe I'm making progress. I have checked my measurements again with another meter and the results are slightly different. The Orange to Yellow and orange to black are the same at 14-15 ohms the Black to Yellow is in fact between 1-2 ohms which is vastly different. I rechecked this again but with an analogue meter and it confirmed the above.

Also your diagram you show does not contain the start relay. Drawing below. I would attempt to wire the motor as to the drawing but it does not respond the way the coils are measured above? What do you think?

Hi Dennis,

The Black to Yellow measurement is worrying; resistance changes on a motor winding may indicate an insulation problem with the windings. I'll have a think. Perhaps an expert could comment?

The diagram sort of shows the start relay. The switch part of the relay is shown below 'Large C'. Assuming it's right, the switch is closed before the motor is turned on, and opened to disconnect Large C as soon as the motor is up to speed. Could be done manually, but that's a pain so many motors have a built-in centrifugal switch that operates automatically. Yours looks to disconnect Large C via a timer relay: I don't know how yours works, could be self-contained, or operated externally.

It's possible that the resistance measurements are misleading because the wires are dirty or not making good contact with the meter probes. Might be worth trying again, several times!

Dave

Eeek! I don't understand that at all. The 'headphones and coil' in a circle on the left is a new symbol to me, and the relay doesn't have a switch. It looks incomplete but may be me - my understanding of relays comes from electronics whereas motor control schematics sometimes use different symbols. Where did the circuit come from?

Dave

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Please Sir ... It's in that document wot I linked on 26th

MichaelG.

SillyOldDuffer

That's one of the two application circuits in the data sheet found by MichealG.

I suspect the "headphones and coil" symbol is some sort of overload current protection device. Maybe the "headphone" part is a bi-metallic strip type switch which opens when excess current makes it too hot.

The relay is current controlled with motor and relay coil in series so current goes through both, At start up the high inrush current operates the relay bringing the start winding in. As the motor runs up to speed the current falls to its normal run value which isn't enough to keep the relay in the on state.

Clive

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