I need some help with my reverse

lectrician1 · Feb 6, 2017

I put a jones rpm meter at full speed reverse and it read 3800 just before the meter flew out of my hand and practically exploded. So no more testing with that meter.

In forward the lathe will only spin 2750

Anybody know why or what I could check
Or remedy the 1000rpm difference between forward and reverse
I have a 1955 wiad 10ee

Also if I put the drum switch in reverse while the spindle is still rotating in forward the contactor Sparks and the ffr relay drops out. The spindle must be completely stopped to put it in reverse
Sometimes if the spindle is moving in forward and I switch it to reverse, it will go in reverse for half a revolution then it will start spinning in forward then ffr relay drops out amidst some sparking from the reverse contactor

Any suggestions?
Thanks in advance
Rich

Monarchist · Feb 6, 2017

lectrician1 said:
I put a jones rpm meter at full speed reverse and it read 3800 just before the meter flew out of my hand and practically exploded. So no more testing with that meter.

In forward the lathe will only spin 2750

Anybody know why or what I could check
Or remedy the 1000rpm difference between forward and reverse
I have a 1955 wiad 10ee

Also if I put the drum switch in reverse while the spindle is still rotating in forward the contactor Sparks and the ffr relay drops out. The spindle must be completely stopped to put it in reverse
Sometimes if the spindle is moving in forward and I switch it to reverse, it will go in reverse for half a revolution then it will start spinning in forward then ffr relay drops out amidst some sparking from the reverse contactor

Any suggestions?
Thanks in advance
Rich

Both are symptomatic of errored brush timing. Covered on PM.

You want a bias toward forward running to have slightly higher no-load RPM, and the smallest of sparks at the brushes. That also optimizes brush life. Reverse will then be at lower RPM, slightly larger sparks. BFD, we don't use it as much as forward.

Your figures sound as it timing is badly out, and also the opposite of what you need.

Bill

lectrician1 · Feb 7, 2017

That brush timing adjustment worked like a charm
Thanks Bill

she's running much better now
3500 in both directions
And it will reverse direction while the spindle is still rotating
at 800rpm, direction change takes about 1.5 seconds

rke[pler · Feb 7, 2017

You might consider adjusting the drive for the 'right' top speed of 4K, it's a couple of tweaks of the adjustment pots you can see on the tombstone. The last part of the adjustment procedure is to get the drive compensation set to reduce RPM changes on load changes.

It also sounds like the anti-plug relay is a bit out of adjustment, you shouldn't be able to reverse until about 200 rpm. If you're not doing it often I wouldn't worry overmuch.

lectrician1 · Feb 7, 2017

My max speed pot does nothing
I set the other three according pots to directions but the max speed doesn't change anything
I remove the pot from the circuit and tested it. It seems ok
Then checked for voltage across-zero
Followed the wires. One side goes to a small doorbell size transformer that was putting out over 240 volts
The other side went to a tube at the botto left side of the tombstone
I changed the tube.
I started getting some voltage across the pot 4or 5 volts.
But it still didn't change the spindle speed

Monarchist · Feb 7, 2017

lectrician1 said:
My max speed pot does nothing
I set the other three according pots to directions but the max speed doesn't change anything
I remove the pot from the circuit and tested it. It seems ok
Then checked for voltage across-zero
Followed the wires. One side goes to a small doorbell size transformer that was putting out over 240 volts
The other side went to a tube at the botto left side of the tombstone
I changed the tube.
I started getting some voltage across the pot 4or 5 volts.
But it still didn't change the spindle speed

Not my area of expertise, but you are not done yet. See post #4 above.

As you correct more and better, no-load speed change will be less apparent.
A goal is to have the reserve to reduce LOADED drop in RPM

Unless you have a dynamometer handy, we have no easy way to measure how well we have accomplished it save to use up some metal as chips, 'real' job or just as a test.

Bill

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