Lathe Reverse

[driftspin]

Attachment 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.

Verstuurd vanaf mijn SM-A320FL met Tapatalk

[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.

Verstuurd vanaf mijn SM-A320FL met Tapatalk

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.....



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

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.

Verstuurd vanaf mijn SM-A505FN met Tapatalk

[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.

Verstuurd vanaf mijn SM-A505FN met Tapatalk

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 :(



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.