G4003 clone, motor won’t reverse.

[Jbrracer]

I can, but first can you repeat a couple of voltage measurements?
With motor disconected, what do you measure between:
U1 and V2 lever up and lever down
Z1 and Z2 lever up and lever down
be careful

It’s gonna be a few hours but I will report back.

Thanks again mark

 

[markba633csi]

Let's revisit post #18 also- I'm going to post a portion of it:

In this configuration placing the carriage lever down the spindle spins toward the tool post.
T1=3 t2=1,5 t3=nc t4=346
B1=u1 b2=v2 b3=nc b4=nc

In this configuration with the lever also down the spindle turns away from the tool post.
T1=3,5 t2=1 t3=nc t4=346
B1=u1 b2=v2 b3=nc b4=nc

So in light of what we have discovered as far as the two 3s, which one is actually 2 here? The one on T1?
I think it must be
I'm going to do a new sketch, hopefully we can wrap this up

 

[markba633csi]

BTW I have a hunch your previous 110 volt readings are ghosts- artifacts caused by leakage to ground
I'll explain later

 

[Jbrracer]

I can, but first can you repeat a couple of voltage measurements?
With motor disconected, what do you measure between:
U1 and V2 lever up and lever down
Z1 and Z2 lever up and lever down
be careful

Mark here’s the report per request
U1 to V2 up is 33/ down is 240
Z1 to z2 up is 240/ down is 40

I did all of them just in case before I had to go on baby duty. I’ll write them up in another post.

 

[Jbrracer]

Let's revisit post #18 also- I'm going to post a portion of it:

So in light of what we have discovered as far as the two 3s, which one is actually 2 here? The one on T1?
I think it must be
I'm going to do a new sketch, hopefully we can wrap this up

Yes 3prime is/was 2

 

[Jbrracer]

Here is the full report

 

[markba633csi]

Darn, that's what I was afraid of- one of the contactors is not working properly. You should have had 240 in all cases
for the tests in post #30
This is looking like a big job- you sure you want to spend the time and money to fix it? It would be far easier (and cheaper) to hook up a drum switch

 

[Jbrracer]

Darn, that's what I was afraid of- one of the contactors is not working properly. You should have had 240 in all cases
for the tests in post #30
This is looking like a big job- you sure you want to spend the time and money to fix it? It would be far easier (and cheaper) to hook up a drum switch

I think I’ll just wire it where I had spindle rotation toward the tool post, and use it for now as is. Once I sell my g4000 I’ll put that money into a vfd and motor. Do you see any problems with that? And if you don’t can we talk about vfd and motor options here or should I start a new thread? Also do you think it would be possible to remove and inspect the bad contactor maybe it just needs cleaned up?

 

[Jbrracer]

Sure. I never ran the lathe with the original wiring, but do still have the control box. I use the reversing switch and wires to control the VFD.

I sent you a pm!
Thanks

 

[markba633csi]

Sounds like a good approach to me- it may not be a broken contactor, there may be a loose wire, or perhaps the apron switch(s) is faulty (fairly common failure point). There's also that fuseholder missing top cap- could that be it? Hard to say without a schematic diagram
For now just kluge it for the one direction- your tests proved that the motor is good.

When these old contactor systems start to fail most of us (me included) usually recommend upgrading to a variable speed setup (vfd, or dc motor and controller). Once you've used a variable speed lathe you'll not want to go back to fixed speed- big improvement
The contactors in these machines are hard to find replacements for and even if you replace the bad one, the others are often right behind it. Just not worth the hassle in my opinion