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Single phase motor - wiring questions

ats101

Nov 11, 2021
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Nov 11, 2021
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Hi guys,

I am new to the forum. I am a chronic tinkerer in the garage and have stumbled across uncertainty regarding wiring in a single phase motor.

Background:

The motor is for a hydraulic scissor lift to raise vehicles. The original motor burnt out. Becuase the vehicle lift was still under warranty, I got sent a new motor. The issue is, none of the wires are labelled and they are all yellow.

I am therefore unable to figure out wires for run winding, wires for start winding. I have opened up rotor bit of the motor and can trace one of the cetrifugal switch wires but the other one is a little more difficult to trace as it has been cable tied to the copper windings. It also means that I cannot remove the motor shaft completly as this wire is fixed.

On the old motor,

There was wiring diagram and each wire was labelled: u1, u2, z1, z2, v1 and v2.

Unfortunately, I don't have this luxury with the new motor.

I have taken some pictures. Please see below.

I have been testing the resistance across wires - the issues is, I cannot make any sense of the values.

If I test switch wire across to other 5 wires I get the following values:

1.6 ohms
4.1 ohms
4.1 ohms
3.3 ohms
4.1 ohms


Doing some research am I correct in thinking the following:

the 1.6 ohms is the other switch wire ?
the 3.3 ohms is probably a start wire?

Are there any other deductions I can make from this?

Remember, the only wire I am certain about, is the one I can visually trace up to the centrifugal switch.

Your help is much appreciated as this is very unhelpful wiring.

Thanks for the help.
 

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Kiwi

Jan 28, 2013
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My initial step would be to contact the supplier.
 

Minder

Apr 24, 2015
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If you can distinguish two separate coil windings, the higher resistance one should go to the Centrifugal SW, the other to the Run winding.
The start capacitor would be in series with the start switch, (high res winding).
How many caps did it come with?
I assume the motor is reversed when in operation?
 

ats101

Nov 11, 2021
14
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Nov 11, 2021
Messages
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My initial step would be to contact the supplier.
Hey man, I am thinking I will send email tomorrow.

I don't get why there is no labelling. Even inside the wire, there is no wiring diagram either.
 

ats101

Nov 11, 2021
14
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Nov 11, 2021
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It runs with 1 starter and 1 run cap.
No the motor is not reversed. It does not need any torque to lower the vehicle.

That's the thing, I can't distinguish.


This guy knows his stuff. He can easily identify the individual coils but then again he has the labels. Can I not use a strategy and simple maths to solve the unknowns.

Am I even looking for the same u1 u2 z1 z2 v1 v2 wiring styles or will it be different?
 

Bluejets

Oct 5, 2014
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Supplier will void any remaining warranty if this motor is not fitted by a qualified lecky.

I'd be inclined to follow that line of action after as Kiwi said, contact the supplier and don't fiddle with it,
Better than even chance you'll end up with 2 stuffed motors and no warranty otherwise.
 

ats101

Nov 11, 2021
14
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Nov 11, 2021
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At this rate, I don't think an electrician would touch it. The motor is wired very differently to the new old one

On the old motor:
v1 and v2 are in continuity
u1 and u2 are in continuity
v1 and v2 are in continuity - this is where the problem was with the old motor. The copper bridg between the two overheated and melted which broke the circuit.

To put it in simpler terms, if I were to test v1 and u2 - I would get no reading for a resistance which means that these are not incontinuity.

Now looking at the new motor. I have been able to identify that each wire has continuity with every other wire. I said in the original post that I can see the switch wire and Ive identified the other switch wire, but why is this is continuity with the other coils? WTF

Please tell me, am I onto something here? the motor is wired very differently.
 

Minder

Apr 24, 2015
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The supplier should be able to tell you the values.
It is reversed by changing relative polarity of the windings, i.e. reverse either the start or the run winding.
 

ats101

Nov 11, 2021
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can anyone explain why the starter winding, run winding switch show continuity between them?
 

Minder

Apr 24, 2015
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If the motor is made or intended for uni-directional, then that would be normal for the ends of both windings to be connected.
BTW it is a start winding switch, not a run winding switch, the run winding would normally be connected all the time.
 

ats101

Nov 11, 2021
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Nov 11, 2021
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But why is the switch wires and winding wires showing a resistance between them?
 

ats101

Nov 11, 2021
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Nov 11, 2021
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If I understand correcty, the run windings and start winding should be separate. As the start winding is used to generate a torque to get it spinning. This is not the case here.

Thanks for all the replies.
 

Minder

Apr 24, 2015
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They are separate windings, but the common of each is often connected to the neutral point in the case of a uni-directional motor, if the motor is to be reversed, the windings are separated in order to reverse one WRT the other.
The centrifugal SW should be connected in series with the start winding.
 

ats101

Nov 11, 2021
14
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Nov 11, 2021
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They are separate windings, but the common of each is often connected to the neutral point in the case of a uni-directional motor, if the motor is to be reversed, the windings are separated in order to reverse one WRT the other.
The centrifugal SW should be connected in series with the start winding.


Thank you for clearing that up.

Therefore, to put it simply, Not all wires in this motor need to be hooked up?
 

Externet

Aug 24, 2009
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If the manufacturer/vendor refuses to clarify things; There is a safe guessy way.
Connect your single phase source in series with a largish incandescent light bulb and try educated combinations of wiring.

Phase-------------------100+W light bulb--------------------------motor-----------------------neutral.
 
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Bluejets

Oct 5, 2014
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If the manufacturer/vendor refuses to clarify things; There is a safe guessy way.
Connect your single phase source in series with a largish incandescent light bulb and try educated combinations of wiring.

Phase-------------------100+W light bulb--------------------------motor-----------------------neutral.

That will light the lamp but that's about all.
It's a rather large motor so I doubt it will turn.
It may give different levels of "slightly dim" if you're lucky.
 

ivak245

Jun 11, 2021
55
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Jun 11, 2021
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This may be a dumb answer, but is there any diagram under the cover for the wiring? There usually is. If the supplier has sent you this to cover a warranty issue, he really should sort this out for you. Good luck with it!
 
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