Single Phase Double Capacitation Induction Motor, YL90L-4, CT043 Craftex Lathe - Motor Wiring and Control

Thread Starter

elissquires

Joined Dec 26, 2021
27
Hi Guys. Did some testing with the below results.

- 25.1 ohms across primary transformer winding
- 25.4 ohms across PC-B1 and PC-B3 when KM1 is closed and and switch is in forward or reverse
- 0.2 ohms across PC-B1 and PC-B3 when KM2 is closed and switch is in forward or reverse
- 0.2 ohms across PC-B2 and PC-B3 when KM1 is closed and and switch is in forward or reverse
- 25.4 ohms across PC-B1 and PC-B3 when KM2 is closed and switch is in forward or reverse
- in any configuration when both KM1 and KM2 are closed, there is 0.2 ohms

Didn't get a chance to wire and test or take a photo of the forward/reverse switch. Will do that later.
 

MaxHeadRoom

Joined Jul 18, 2013
28,515
So we are back to the contactor??
I though the plan was to wire it direct for one direction in order to test the motor/caps/cent.-SW first?
 

LesJones

Joined Jan 8, 2017
4,174
Those readings suggest that the reversing circuit is reversing the polarity of of PCB1 and PCB2 between forward and reverse which is what is required for the normal way of connecting a capacitor start / capacitor run motor. This agrees with the schematic of the control box shown in post #1. In the first picture in post #1you show three wires plus an earth wire coming out of the flexible conduit. Can you look at the other end of the conduit at the control box end and count the number of wires entering it ? I am thinking that the missing wire may be broken inside the conduit.

Les.
 

MisterBill2

Joined Jan 23, 2018
17,833
Les/Max, I've attached your wiring diagram with connections to PC wires. I'll give this a shot.

Bill, the starting capacitor is definitely isolated by the centrifugal switch, not the running capacitor. That said, I'm still not convinced that the switch is operating as it should. Maybe the motor is not reaching sufficient speed to disconnect due to my inferior hookup...

I'll take a photo of the forward/reverse switch. It's buried under the gearbox, so I won't be able to get a great one, but I'll do my best.
My concern was that perhaps the two capacitors became exchanged. The start capacitor should be the larger value.
To monitor the switch you can attach test leads to the two sides snf then see if you get a voltage when the motor is done accelerating. If no meter is available use a low wattage mains voltage light bulb.
 
Last edited:

LesJones

Joined Jan 8, 2017
4,174
MisterBill2, The diagram in post #10 indicates that the capacitors and centrifugal switch are wired correctly. I have not noticed anything to indicate that the start and run capacitors have been swapped over.

elissquires , Just thinking that the centrifugal switch is not working is not good enough. Do the test suggested in post #65.
Or add a switch in series with it and manually open the switch once the motor is rotating.
Wiring the motor as drawn in posts #44 and #56 will not work when connected to the PCB connections. If you want to try it feed it from the mains via a suitably rated fuse or circuit breaker.
Your results in post #62 indicate that the reversing switch is not wired to work with the circuit in posts #44 and #56.
Have you counted the wires entering the control box end of the flexible conduit ?

Les.
 

MisterBill2

Joined Jan 23, 2018
17,833
MisterBill2, The diagram in post #10 indicates that the capacitors and centrifugal switch are wired correctly. I have not noticed anything to indicate that the start and run capacitors have been swapped over.

elissquires , Just thinking that the centrifugal switch is not working is not good enough. Do the test suggested in post #65.
Or add a switch in series with it and manually open the switch once the motor is rotating.
Wiring the motor as drawn in posts #44 and #56 will not work when connected to the PCB connections. If you want to try it feed it from the mains via a suitably rated fuse or circuit breaker.
Your results in post #62 indicate that the reversing switch is not wired to work with the circuit in posts #44 and #56.
Have you counted the wires entering the control box end of the flexible conduit ?

Les.
Given that the junction box was so very damaged that the wire numbers were not usable it is reasonable to suggest verifying that the caps are correct. At one job I did need to trace out connections in a fair sided machine that had fallen out of a truck. The destruction was impressive. The repairs had to be extensive.
 

Thread Starter

elissquires

Joined Dec 26, 2021
27
I've visually and electrically verified that the capacitors are not swapped. I'll get some info and get back on the remainder of the questions.
 

Thread Starter

elissquires

Joined Dec 26, 2021
27
I'm rigging up a switch to directly wire the motor for testing. Will put a clamp on ammeter when I test it. It's on a 15 A breaker as well. Here's a couple of pics of the switch on the machine. Wish you were! Would save me fumbling around. No extra wires in the conduit to the motor.
 

Attachments

MisterBill2

Joined Jan 23, 2018
17,833
OK, that looks like a rather strong arrangement. Then there must be some power contactors someplace else. That is a better arrangement than a drum switch and lots of wires.
The capacitors question was worth investigating, but it might be that the starter switch is not opening. That would produce the similar symptom.
 

Thread Starter

elissquires

Joined Dec 26, 2021
27
Good Evening. Put a switch in my 220V circuit and directly wired the motor with 220V as shown in the diagram below. 15A circuit breaker in the panel. Put my clamp on ammeter (Fluke) around one of the 220V wires feeding the motor. When switched on, the motor immediately pulled up through 50A and climbing so I shut it off. I'm sure the breaker would have tripped momentarily. I think we can safely say that the lathe wiring is not the problem. Either the motor is malfunctioning, or I have wired it wrong.
 

Attachments

MisterBill2

Joined Jan 23, 2018
17,833
I just realized that it has not been verfified that the motor is not short circuited to the frame. That is simple to check for with a multimeter that has a resistance measuring function available.
 

LesJones

Joined Jan 8, 2017
4,174
MisterBill2 makes a good point. With your meter set to a high resistance range (Assuming it is not auto ranging.) and with none of the motor connections connected to each other or anything else. Connect one meter lead to the motor frame and then connect the other meter lead to each winding in turn and then to the black and the blue wires from the capacitors / centrifugal switch circuit. All the readings should be at least several megohms. (They will probably be high enough for the meter to indicate over range.)
I don't know what the picture in post #72 of the blue cable plugged into a power socket is supposed to show us.
Can you post a picture of your motor wiring so that we can follow ALL the wires and read the labels on the motor wires. This is to confirm that you have wired it according to the diagram.

Les.
 
Last edited:

MisterBill2

Joined Jan 23, 2018
17,833
I think that it was back in post #1 that the TS explained that all of the original lead markings were lost, and so the markings on the leads are new, and bear no relation to the original identifications. So now one more question: Is it at all possible that the motor is a 120 volt motor, not intended for 240 or 220 volt operation? That would explain a lot, and if it worked that would be a really chep fix. But still I recommend verifying the start switch correct operation first.
 

MisterBill2

Joined Jan 23, 2018
17,833
If it would run on 120 I wonder if it would produce enough torque. I am thinking that would draw less current, and possibly not trip the overload device.
And an interesting thought is to just disconnect the starting capacitor and see what happens with a no-load connected start attempt. If it starts and then runs OK, you will know it is a start witch problem.
 
Top