Electric snafu. Restoring a 10" south bend. 3 phase 1 hp motor. Runs fine in forward, but kicks out after 5 minutes in reverse.

w. nolan jett · Dec 30, 2022

Electric snafu. Restoring a 10" southbend. 220 1 hp 3 phase motor. Runs fine in forward but kicks out after 5 minutes in reverse.

neilho · Dec 31, 2022

When you write "kick out" what does that mean? One of the thermal overloads disconnects?

moonlight machine · Dec 31, 2022

Its a south bend, everybody knows the chuck will fall off if you run it in reverse!

w. nolan jett · Dec 31, 2022

It has a D1-4 spindle mount, so no chuck unscrewing. yy
the thermal overload breaker mounted behind the lathe kicks out. There is a reset that works quickly to restore service. Powered by a phase converter.

II

w. nolan jett · Dec 31, 2022

JBTR · Dec 31, 2022

What type of phase converter are you using?

Am I assuming correctly that the lathe is using the stock control box/starter (such as from Furnas Electric) and reversing switch, and that the 3-phase power input to the lathe is connected to the output of the phase converter?

And that you are pressing the button on that control box to reset the thermal breaker?

jmm03 · Dec 31, 2022

if it is a phase converter that is generating the third leg it could be dropping out in reverse due to switching the line leads and causing a voltage imbalance on the generated leg. have you put a clampon ammeter on it to monitor the draw?

w. nolan jett · Dec 31, 2022

JBTR said:
What type of phase converter are you using?

Am I assuming correctly that the lathe is using the stock control box/starter (such as from Furnas Electric) and reversing switch, and that the 3-phase power input to the lathe is connected to the output of the phase converter?

And that you are pressing the button on that control box to reset the thermal breaker?

Thats a fact, jack!

w. nolan jett · Dec 31, 2022

jmm03 said:
if it is a phase converter that is generating the third leg it could be dropping out in reverse due to switching the line leads and causing a voltage imbalance on the generated leg. have you put a clampon ammeter on it to monitor the draw?

Thanks, I'll look at it.

w. nolan jett · Dec 31, 2022

jmm03 said:
if it is a phase converter that is generating the third leg it could be dropping out in reverse due to switching the line leads and causing a voltage imbalance on the generated leg. have you put a clampon ammeter on it to monitor the draw?

Thanks, I'll look at it.

Ohio Mike · Jan 1, 2023

w. nolan jett said:
Thanks, I'll look at it.

Old school overloads with heaters only worked on two legs. The newer code compliant ones have protection on all three legs. Try to get the pass thru legs on the overloads and the "wild leg" bypassed. Then if the switch is backwards swap those two legs.

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Electric snafu. Restoring a 10" south bend. 3 phase 1 hp motor. Runs fine in forward, but kicks out after 5 minutes in reverse.

w. nolan jett

Plastic

neilho

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moonlight machine

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w. nolan jett

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JBTR

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Ohio Mike

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