Motor control switch

[MyLilMule]

Not specific to South Bend, but I have a 220v single phase motor on my lathe. I need to replace the current switch that only has a start and stop button.

The motor is reversible when used with a couple control lines. I want the replacement switch to have a forward and reverse button as well as the stop button. The current switch is on the original bracket, but that places it in a spot in which you have to reach over the spinning chuck in order to turn it off. I plan to move the new switch to one of the guards covering the cone pulley. Much safer position.

I’d like to see what others have done with their lathe. And also where you bought your switch from. Since my motor is not DC, there are two control lines, depending on how they are connected, determines the direction the motor turns. It’s not anything I’ve been able to find that seems correct.

 

[benmychree]

A drum switch would be better and simpler than a push button setup.

 

[MyLilMule]

I fail to understand why.

 

[markba633csi]

A push button system with latching relays would be safer in my opinion. The problem with drum switches and capacitor start single phase ac motors is that the motor has to come to nearly a full stop before it will reverse. Otherwise, if you throw the switch quickly into reverse the motor will continue to run in the forward direction
-Mark

 

[tq60]

And relays release on power fail.

Sent from my SAMSUNG-SM-G930A using Tapatalk

 

[MyLilMule]

I'm looking for something similar to this. Not quite 1941 vintage, but it doesn't scream 2021 either. I question whether something like this would have internal latching relays, however. And I'm not overly concerned about power failures.

 

[benmychree]

The fact is that nearly all South Bend lathes were fitted with drum switches as manufactured --- and using latching relays does nothing to prevent continued rotation when the rotation is reversed at the push button switch. It seems that so many folks are going to frequency drives that the use of split phase and capacitor start motors, the the issue seems moot. If I were using a lathe for tapping, for instance, that a push button latched starter would make it less likely for the reversal to occur in a timely fashion, with broken taps as the result. Personally, I think the use of a drum switch with 3 phase power is the best of all worlds, whether the source of power comes from a phase converter or a frequency drive.

 

[MyLilMule]

The fact is that nearly all South Bend lathes were fitted with drum switches as manufactured ---

Appreciate your feedback and view point. I agree that is the way they were manufactured. But as of now, I don't think that is what I want. And I don't plan to keep it in the as-manufactured position, so it doesn't matter.

 

[markba633csi]

John is correct, the 3-phase approach is preferable and simpler
It would be difficult to build a true lockout for the push button case. You would almost need a speed sensor on the motor
or have the motor start circuit connected back to the buttons somehow

 

[ddickey]

I'm looking for something similar to this. Not quite 1941 vintage, but it doesn't scream 2021 either. I question whether something like this would have internal latching relays, however. And I'm not overly concerned about power failures.

That looks like a maintained push button switch. No relay needed.