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Re: 220V single phase Lathe motor stopped reversing [Re: Sniper] #2808289
08/12/20 11:54 PM
08/12/20 11:54 PM
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6PakBee Offline
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I hated to wade into the polarity discussion but Sniper is correct. What reversing the connections on the start winding does is change the phasing between the start and run windings. The two different configurations changes what direction the motor turns as the relative phasing between the two windings changes. Apparently you have two contactors for the reversing function rather than a full voltage reversing switch. All this means is that the switches controlling the contactors are functioning and one of the contactors is not. As to the comment from the vendor that a clicking contactor means it is working is pure bull. As to the motor trying to start, the slight movement you are seeing is pretty common with an open start winding. With the additional information, I'm still betting that you have a switching problem it's just now that it is a contactor rather than the switch itself.


"We live in a time when intelligent people are being silenced so that stupid people won't be offended".
Re: 220V single phase Lathe motor stopped reversing [Re: 6PakBee] #2808364
08/13/20 09:34 AM
08/13/20 09:34 AM
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Quote
What changes in multiphase power is when the peaks occur in time in relation to each other. By shifting that peak in time you can reverse the motor and that's what starting caps do when starting a single phase motor.

Two phase sine wave shown.

[Linked Image]


So if I am interpreting what you are saying correctly, the problem is likely the one of the contacts in the contactor, or the Reverse starting capacitor which I'm assuming is inside one of the two large enclosures on top of the motor. Correct?

Thanks Again for all the help. smile



Last edited by TJP; 08/13/20 09:43 AM.
Re: 220V single phase Lathe motor stopped reversing [Re: TJP] #2808378
08/13/20 10:11 AM
08/13/20 10:11 AM
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I’m certainly not as knowledgeable as the one guy but my pump motor would just hum not start and ended up being the capacitor. Over the years in my dusty shop (wood) I have cleaned every motors contacts (3 phase and single phase) many times (magnetic type) Today’s motors are tough cookies and never had one just stop other than an external problem. If they do fail it’s in a long overworked death type struggle.

Re: 220V single phase Lathe motor stopped reversing [Re: 6PakBee] #2808577
08/13/20 05:29 PM
08/13/20 05:29 PM
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Morrow, OH
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Originally Posted by 6PakBee
I hated to wade into the polarity discussion but Sniper is correct.


I don't have the energy to argue why using polarity is acceptable terminology in this case. A current transformer (CT) is an AC device and yet it is marked with polarity. Same concept. I don't care if you call it phasing or polarity, I think we all agree on how it works.

Usually the forward and reverse capacitors are the same capacitor.


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Re: 220V single phase Lathe motor stopped reversing [Re: markz528] #2808584
08/13/20 05:47 PM
08/13/20 05:47 PM
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And contactors absolutely do fail............. Lots of times easily fixed.


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Re: 220V single phase Lathe motor stopped reversing [Re: markz528] #2808626
08/13/20 07:27 PM
08/13/20 07:27 PM
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Originally Posted by markz528
Originally Posted by 6PakBee
I hated to wade into the polarity discussion but Sniper is correct.


I don't have the energy to argue why using polarity is acceptable terminology in this case. A current transformer (CT) is an AC device and yet it is marked with polarity. Same concept. I don't care if you call it phasing or polarity, I think we all agree on how it works.

Usually the forward and reverse capacitors are the same capacitor.



OK, then you are saying likely the Reverse contactor ?
Quote
Usually the forward and reverse capacitors are the same capacitor.


This is why I get a bit confused I understand the A/C portion of the sine wave and that the difference between the high and low peaks equal the V. If I remember correctly the high was considered Plus V while the low was the opposite or negative.

thanks again to all who are trying to make me understand what I long ago forgot due to not using it smile

Re: 220V single phase Lathe motor stopped reversing [Re: markz528] #2808691
08/13/20 10:22 PM
08/13/20 10:22 PM
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Originally Posted by markz528
Originally Posted by 6PakBee
I hated to wade into the polarity discussion but Sniper is correct.


I don't have the energy to argue why using polarity is acceptable terminology in this case. A current transformer (CT) is an AC device and yet it is marked with polarity. Same concept. I don't care if you call it phasing or polarity, I think we all agree on how it works.

Usually the forward and reverse capacitors are the same capacitor.



Why does a CT have a polarity marking? because it refers to the direction of current flow and has nothing to do with voltage.

Re: 220V single phase Lathe motor stopped reversing [Re: TJP] #2808784
08/14/20 09:16 AM
08/14/20 09:16 AM
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Originally Posted by TJP
Originally Posted by markz528
Originally Posted by 6PakBee
I hated to wade into the polarity discussion but Sniper is correct.


I don't have the energy to argue why using polarity is acceptable terminology in this case. A current transformer (CT) is an AC device and yet it is marked with polarity. Same concept. I don't care if you call it phasing or polarity, I think we all agree on how it works.

Usually the forward and reverse capacitors are the same capacitor.



OK, then you are saying likely the Reverse contactor ?
Quote
Usually the forward and reverse capacitors are the same capacitor.


This is why I get a bit confused I understand the A/C portion of the sine wave and that the difference between the high and low peaks equal the V. If I remember correctly the high was considered Plus V while the low was the opposite or negative.

thanks again to all who are trying to make me understand what I long ago forgot due to not using it smile



That's why I said I didn't want to wade into a discussion about polarity. If you understand AC circuits, polarity is fine. The problem is when car people used to dealing with automotive DC systems hear the term polarity they assume a DC circuit. But I agree that we all agree on how it works. up As to capacitors, there is only one start capacitor on a capacitor start motor and more than one capacitor on a capacitor start/capacitor run motor. But I have never seen a dedicated capacitor for forward and another for reverse. As to the thinking that it is the reversing contactor (now that we know you don't have a simple switch) I think that's what everyone is saying. If you want to prove to yourself which is the case, swap the forward and reverse contactors, I'll bet your problem follows the contactor.


"We live in a time when intelligent people are being silenced so that stupid people won't be offended".
Re: 220V single phase Lathe motor stopped reversing [Re: Sniper] #2808829
08/14/20 11:12 AM
08/14/20 11:12 AM
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Originally Posted by Sniper
[quote=markz528] Why does a CT have a polarity marking? because it refers to the direction of current flow


Exactly!

And yes, I would be looking at your reverse contactor.


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Re: 220V single phase Lathe motor stopped reversing [Re: markz528] #2809028
08/14/20 07:51 PM
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Thanks again and i will keep you posted as to the outcome beer

Re: 220V single phase Lathe motor stopped reversing [Re: TJP] #2809327
08/15/20 08:44 PM
08/15/20 08:44 PM
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I am more than ready to take my beating now spank spank spankl

Well much to no one's surprise, those of you that said it was a contactor issue are likely right. I say so as the new BALDOR motor arrived an was installed per their instructions that I found on the net dated 2018 with pictures and a table on converting existing connections to the new motor. They were wrong directional wise to my machine but that was easily corrected.
As predicted the unit still will not run in reverse, Unless of course I switch wires Z1 znd Z2 also known as 5 & 8 or T5 and T8 per Baldors instructions. Then it will happily run in reverse, but not forward, Once again as predicted.
My other concern at this time is the motor has a hum or slight vibration while running. I will try it with the belts disconnected to see if it may be due to an alignment issue. I will also verify that the line voltage is hooked up to the correctly.
meanwhile I found a replace contactor on ebay for a pretty reasonable price but before I blow my wad again I thought i might see if there was any further input.
I'm attaching a couple of pic's in case they might be helpful . I at this point am assuming U1 & U2 are the run windings and the Z1 or Z2 control the direction on start up yes ???

Thanks again for all the assistance


Lathe schematic.jpgBaldor instr.jpg
Re: 220V single phase Lathe motor stopped reversing [Re: TJP] #2809401
08/16/20 08:30 AM
08/16/20 08:30 AM
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North Dakota
6PakBee Offline
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Page 8 should answer your questions.

Motor Connections

But to expound a bit, there is no such thing as a 'control' winding. There is start and there is run. The connection configuration determines the relative phasing between the two and they both determine rotation. The only reason the non-reversible single phase single voltage capacitor start motor has only two terminals is that the start winding is internally connected.


As to single phase capacitor start motors, I like (and buy) a TEFC enclosure. The point of failure on a single phase is typically the internal centrifugal starting switch and a TEFC prevents airborne crud getting into the motor that an open or open drip-proof enclosure will.


"We live in a time when intelligent people are being silenced so that stupid people won't be offended".
Re: 220V single phase Lathe motor stopped reversing [Re: 6PakBee] #2809582
08/16/20 07:19 PM
08/16/20 07:19 PM
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I don't see a problem here, I mean the unused one on the right looks new wink And the other one ??/ that's black conductive carbon meant to enhance the current capacity LOL
Thanks to ALL for the assistance bow bow bow beer

DSC00669.JPG
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