Lathe Reverse

[blackburn mark]

Hoping someone can verify my assumptions:
This is the motor on my Boxford VST (has one capacitor outside the chassis)

27878

27876

My assumption is that by rotating the bars 90 degrees (red lines) the motor will run in reverse.....?

[driftspin]

Hoping someone can verify my assumptions:
This is the motor on my Boxford VST (has one capacitor outside the chassis)

27878

27876

My assumption is that by rotating the bars 90 degrees (red lines) the motor will run in reverse.....?Hi Mark,

I think some of us can.

It is just that i would want to see where the capacitor wires are going. just to be sure.

Basically one moves 1 power lead from one side of the capacitor to the other.

I cant really see where all wires are connected now so...

I guess you have this setup.

http://www.electricneutron.com/wp-content/uploads/2014/12/reverse-rotation-capacitor.jpg


Grtz Bert.

https://www.google.com/amp/s/www.electricneutron.com/electric-motor/use-three-phase-motor-single-phase-power-supply/amp/



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[blackburn mark]

Cheers for that... ill have to remove the block tomorrow and take a look as they come in from the back.

[blackburn mark]

I have fitted a switch that impliments the bus bar change... it will now run in reverse ok but i get a single thud in foward but no rotation
I swapped live and nutral which i didnt think would make any diffrence but i am now assuming if a swap them back over, it might run forward but not in reverse....?

27965

27966

If there is something obvious I'm doing wrong, let me know :)
If not, i shall continue the hunt for infomation on this motor.

[Sterob]

I helped a mate repair his single phase lathe a couple of years ago after the starting switch fell apart and someone lost some of the parts!
I had trouble reversing the motor ( think it had a cap on it....)
I found that the 'run winding' was centre tapped and , which was neutral and the Active was swapped to either end of the winding to change direction.
This meant that single phase lathe and the 3 phase lathes could use the same sort of drum switch, ie FOR- Off - REV.
I did a drawing but its at work.

Yours may be the same.


I have Rosenburg ( Electric Motor Bible) and there is only a very small mention of this sort of motor in it!

[m_c]

How it changes direction, depends on what kind of capacitor setup is being used.

Essentially you need to swap how the two windings and capacitor are connected. If all you're getting is a thud, it sounds like you've missed the capacitor out of the circuit, or have shorted the capacitor out.
I have tried searching for a suitable diagram, but have so far came up with nothing simple.

I'd suggest putting it back to how it was, then try reversing direction with the bus bars.
If that doesn't work, try moving the capacitor connection by moving the right/outer connection.

[blackburn mark]

I think I might have cracked it.....
I have wired the cap to pin 4 instead of pin 2 (my error // I think my drawing is correct but my actual wiring is wrong)
So in forward, pin 2 is not seeing the cap but in reverse it is.... ill know in an hour or so if I can get my hands in there with a mirror a light and a spanner :)

[blackburn mark]

No joy....
Now it will run forward but not in reverse...…
This has me baffled.


It will run forward but not reverse with the Cap on pin2
It will run reverse but not forward with the Cap on pin4


27976

This switching scheme rotates the removed bus bars through 90 degrees, is there a way I could cause damage by trying the cap on the other two pins?

[Clive S]

Have you seen this vid https://www.youtube.com/watch?time_continue=221&v=__nS3OelY-s&feature=emb_logo

I take it, it is a single phase motor with a capacitor

When your motor runs up to speed do you here a click and another when it slows down.

[blackburn mark]

Hi Clive
Its single phase according to the plate and it has a single capacitor
I hear no click on the run-up or run-down

Its an old Clarke motor that yields very little when run through google :(

[Clive S]

Hi Clive
Its single phase according to the plate and it has a single capacitor
I hear no click on the run-up or run-down

Its an old Clarke motor that yields very little when run through google :(

Do you know how it was wired originally. Watch the vid till the end

[driftspin]

I have fitted a switch that impliments the bus bar change... it will now run in reverse ok but i get a single thud in foward but no rotation
I swapped live and nutral which i didnt think would make any diffrence but i am now assuming if a swap them back over, it might run forward but not in reverse....?

27965

27966

If there is something obvious I'm doing wrong, let me know :)
If not, i shall continue the hunt for infomation on this motor.To reverse in the schematic i posted earlier we may assume the right lead is neutral.

Then the left lead is fase.

when you move the fase wire to the top the motor will reverse direction.

You should check what i am saying next.
In the picture you posted i think the motor wires are all on the bottom row.

Starpoint of the motor is hidden.

Did you draw in green where the actual capacitor is ?





Grtz Bert

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[blackburn mark]

Do you know how it was wired originally. Watch the vid till the end

27978
In its original wiring, it runs counter-clockwise as I face the shaft.... I can get it to run clockwise by rotating the bus bars through 90 degrees BUT I have to also move the Cap from pin2 to pin4 which seems odd and I don't have enough pins in the tumbler switch I have in order to implement that.
I was hoping an expert would reveal how dumb I was and say something like "you reverse it by moving the cap only" :nightmare:



I did, I don't know much about AC motor schemes but that motor looked (and sounded) like a different beast to mine.

[blackburn mark]

To reverse in the schematic i posted earlier we may assume the right lead is neutral.

The left lead is fase.

when you move the fase wire to the top the motor will reverse direction.


Grtz Bert

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27979

27980

Are you saying I just move the capacitor like this or am I doing as I have been and moving the capacitor AND rotating the bus bars?
You will have to excuse my poor grasp of AC motors

[blackburn mark]

27982

Or this....?


We are seeing this from different perspectives my good man :cheerful:
I have a very poor grasp of the underlying/fundamental functions of the varying flavours of AC motors
If this image represents my conundrum, it does so in an abstract that I am struggling to convert into pin numbers.
I don't know how I get four pins from the three nodes

[blackburn mark]

Ah... wait a minute... the three sets of two pins... :whistle:
My apologies Bert.
I think I'm gaining some perspective, I need to have a ponder on what is going on.

[driftspin]

27982

Or this....?


We are seeing this from different perspectives my good man :cheerful:
I have a very poor grasp of the underlying/fundamental functions of the varying flavours of AC motors
If this image represents my conundrum, it does so in an abstract that I am struggling to convert into pin numbers.
I don't know how I get four pins from the three nodesHaha yes last 2 pictures work for me.

There is no real difference.
effect is the same.


The bus bars i am not sure of until we know where u1 v1 w1 motor wire go.

What is confusing in the picture is what wires are capacitor and what is the power cord.

Normally motorwires are all below the busbar no need to mess arround with them.

looks like u2 v2 w2 starpoint is hidden in this motor.

Grtz Bert.

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[driftspin]

Haha yes last 2 pictures work for me.

There is no real difference.
effect is the same.


The bus bars i am not sure of until we know where u1 v1 w1 motor wire go.

What is confusing in the picture is what wires are capacitor and what is the power cord.

Normally motorwires are all below the busbar no need to mess arround with them.

looks like u2 v2 w2 starpoint is hidden in this motor.

Grtz Bert.

Verstuurd vanaf mijn SM-A320FL met TapatalkJust make sure the capacitor never touches both fase and neutral directly, it will blow the fuse and capacitor too i think.

Grtz Bert

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[blackburn mark]

27984


The u1 v1 w1 (as you call them) must be the three white wires under the "X" symbols
I might be able to make sense after some drawing and thinking :)

[driftspin]

Do you know how it was wired originally. Watch the vid till the endThat is my question now too.

I would expect all motor wires on 1 side actually... may my bad.

Do we agree on the schematic?

Grtz Bert.

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[driftspin]

27984


The u1 v1 w1 (as you call them) must be the three white wires under the "X" symbols
I might be able to make sense after some drawing and thinking :)If i had to make it run reverse i would move the power cord blue wire to the left bottom contact IE the other side Capacitor termination.

Grtz Bert.

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[blackburn mark]

If i had to make it run reverse i would move the power cord blue wire to the left bottom contact IE the other side Capacitor termination.

Grtz Bert.

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You mean like this?
That would be bliss as I may be able to implement that without removing the motor again (infinitely variable drive and its a bitch)

What's the chances of blowing something if I give it a try and its in Delta or some other strange format?

[blackburn mark]

I would expect all motor wires on 1 side actually... may my bad.



I would too but I'm assuming its been dropped onto that pin for lazy convenience // the fact that it uses bus bars tells me all those pins are isolated so one is as good as another :)

[m_c]

The wiring depends on what kind of single phase motor it is.
You will likely find there are 2 coils (your main run winding, then a smaller start winding) with all wires brought out to the terminals.

IIRC to change direction, you need to switch the position of the start winding/capacitor, however it's been a good few years since I've looked at a suitable diagram to be 100% sure about that.

[blackburn mark]

The wiring depends on what kind of single phase motor it is.
You will likely find there are 2 coils (your main run winding, then a smaller start winding) with all wires brought out to the terminals.

IIRC to change direction, you need to switch the position of the start winding/capacitor, however it's been a good few years since I've looked at a suitable diagram to be 100% sure about that.

I "think" I may have cracked the logic of what I am seeing.....

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Having not taken note of the drum switch position, it is possible that in both forward and reverse working conditions, the only change had been the capacitor (its hard to describe the logic, its been a bit of a Rubik's cube)

I'm stuck at work for three days now so I cant test yet.... I think you guys talking of a capacitor switch were on the right track.

Cheers for the help guys, you may have saved me from surrendering the cash and lumping for an inverter and three phase motor.

I might finally get some use out of my thread cutting gearbox now (its metric so I cant easily disengage without losing position - I can just reverse out)

[m_c]

There are 3 variations of common induction single phase motors.

The fact you've only got one capacitor rules out the Capacitor Start / Capacitor Run option (provides the best of both options below)
You say you don't hear a click, which likely rules it out being a Capacitor Start motor (gives more starting torque, but adds the complexity of a centrifugal switch)
So it's likely you have a Capacitor Run motor (gives very little starting torque, but helps the motor run a bit smoother)

They ultimately all work in a similar way, with a second (usually weaker) winding, that uses a capacitor to create a delayed phase, otherwise the motor will simply vibrate between poles when you apply AC power.
The bigger the capacitor, the more power the second winding gets (more starting torque), but the more the windings will heat up due to the relationship between the power, the motors inductions causing the windings to essentially fight against each other (hence why a Cap Start motor relies on a switch to disconnect once running, otherwise the motor would overheat quite quickly).

You just need to move the capacitor's position so it creates the delayed phase in the correct direction, but I can never remember the connections.

[blackburn mark]

There are 3 variations of common induction single phase motors.


Most of that is rocket science to me... I get the general, gist I think.

I am running on the deduction that IF cap on pin2 = Forward and the cap on Pin4 = Reverse then the bus bars cannot be jumpered twixt Pin2 and Pin4 for reverse because that would eliminate any need to swap the cap from Pin2 to Pin4 so I have been unknowingly / randomly jumpering pins via the tumbler switch until I hit (1<----->2) + (3 <------> 4) where it will run in either direction depending only on the capacitor placement.

Having said that, I was 99% sure I had cracked the problem earlier and I was wrong so I'm going with 98% this time
28012
This and other similar images had me convinced it was all in the bus bars.


I wont know for sure until Sat.

[driftspin]

Hi,

After seeing the documentation sheet I do not think your motor is like the schematics I posted earlier. Is it the sheet from your motor?

I think you might have been right then, if no one has been playing with the motor wiring and bus bars before you took the picture.




Grtz Bert.

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[blackburn mark]

Hi,

After seeing the documentation sheet I do not think your motor is like the schematics I posted earlier. Is it the sheet from your motor?

I think you might have been right then, if no one has been playing with the motor wiring and bus bars before you took the picture.




Grtz Bert.

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No, its not my document, it is one that looked like many others with the bus bars but I'm pretty sure its not how mine is wired.
The motor looked like it had been messed with a bit but it ran ok in forward.....

I am half way through rewiring it for a simple capacitor pin swap but its getting a bit tight in there so might have to surrender and pull the motor out.

[blackburn mark]

My hypothesis has failed under test :(

28050

My confidence with logic is fooked!
I can get it to work in reverse under some strange setup that I cannot get a clear perspective on.... its back to the drawing board.

[driftspin]

Do you have a dmv?

It would help to measure resistance with bus bars of and capacitor disconnected

Then we might get a clue on where the coils are connected.



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[m_c]

I just had another quick search, and this came up - http://www.sentridge.com/wp-content/uploads/wiring_1ph.pdf

It's not exactly like your wiring, however it should point you in the right direction, provided you work out how your coils are connected to your terminals.
I'm a bit tired, but I think your main coil will be connected diagonally (middle left, to top right in your diagram), with one end of the secondary coil bottom right, and the other top left.
If you remove all the jumpers, a quick test with a mutlimeter should confirm/reject that.

[blackburn mark]

That was a nightmare.... I had a dud contact on my (cheap as chips) rotary switch.
I thought I was going mad, the logic had gone all twilight zone!

I now have a lathe that works in forward and reverse.... CHEERS GUYS!
It is just a simple case of moving the two jumpers / bus bars through 90 degrees on this motor (or adding a switch to do just that)

Clarke Motor M80 BL4
28054

Cheers for the link M_C
I had seen a few similar those but that was a good one!

Driftspin: dmv?
I was going to pull the motor out and measure all the winding wires but I thought I would give it one last run through as the logic seemed to be pointing to an strange anomaly or fault somewhere.

[Clive S]

That was a nightmare.... I had a dud contact on my (cheap as chips) rotary switch.
I thought I was going mad, the logic had gone all twilight zone!

Glad you sorted it Mark :applouse:

[driftspin]

That was a nightmare.... I had a dud contact on my (cheap as chips) rotary switch.
I thought I was going mad, the logic had gone all twilight zone!

I now have a lathe that works in forward and reverse.... CHEERS GUYS!
It is just a simple case of moving the two jumpers / bus bars through 90 degrees on this motor (or adding a switch to do just that)

Clarke Motor M80 BL4
28054

Cheers for the link M_C
I had seen a few similar those but that was a good one!

Driftspin: dmv?
I was going to pull the motor out and measure all the winding wires but I thought I would give it one last run through as the logic seemed to be pointing to an strange anomaly or fault somewhere.YES sorry, typo dvm.
Digital volt meter.




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