Need help with lathe finish

[kenickie22]

I’m curious what the condition is of that switch labeled SA1

Also looks like your control transformer is connected between terminals S&T. I’d double check to make sure your generated leg is not on one of those terminals.

Thanks guys. I will try and check that switch when I get home tonight.

How do I tell which is my generated leg?

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[kenickie22]

I’m curious what the condition is of that switch labeled SA1

Also looks like your control transformer is connected between terminals S&T. I’d double check to make sure your generated leg is not on one of those terminals.

Bentworker, I think the SA1 switch is ok. Nothing looks burnt anyway.

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[kenickie22]

The terminal for the black wire was definitely burnt.

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[kenickie22]

Nothing appeared to be burnt in here. https://uploads.tapatalk-cdn.com/202005 ... 0925bb.jpg



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[kenickie22]

I replaced the terminals and have made some test cuts, but haven't done any threading. The finish looks the same as the previous pictures.

Any other ideas? Thanks!

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[whateg0]

Did you check to make sure the connections were correct, as suggested?

Dave

[kenickie22]

Did you check to make sure the connections were correct, as suggested?

Dave

Hi Dave. I'm unsure of how to tell which is the generated leg?

Here are the voltages - lathe spindle off is the first value & spindle on is in parentheses:
L1/L2 = 262v (220v)
L1/L3 = 282v (245v)
L2/L3 = 250v (250v)

My phase converter is running from a 250v appliance plug. The power for the plug is coming from 2 125v 50a breakers. The box is about 15' from the plug.

The converter is rated for 3HP/15A.

On low speed the motor is 2HP/8.1A.

I put an amp clamp on each leg with the spindle on, and read less than 2A for each.

I'm trying to run in low speed only, as I believe my converter is too small to run in high speed.

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[kenickie22]

Is the generated leg the one that checks 240v to ground? If so, it is connect to R on the diagram.

[John Hasler]

Is the generated leg the one that checks 240v to ground?

Yes.

[Bentworker]

It is impossible to judge the condition of the switches from the outside appearance. I’d suggest you get a multimeter and do some testing to prove function of the switches

[charkmandler]

Another thing to look at - I have always preferred to run my belts on the looser side than too tight (just a fraction). My lathe turned with a good finish and I could part large diameters / heavy cuts with no problems. Recently turning with a profile tool caused bad chatter, next parting was was near impossible, then surface finish deteriorated a bit. All gibs were good etc.
The cause - the belt had really loosened off and must have been chattering / slipping. Tensioning the belt back solved all the issues.
A belt that is too tight can also cause finish problems.
Something worth looking at.

[Jerry_H]

Looks to me like the black wire on the burnt terminal may have been lose. Lose =extra resistance =high heat=burn.

Jerry