South Bend wiring!

First off thanks for all the info this site has provided thus far. I am having trouble wiring my new Lesson 1/4 hp motor to my south bend 9" lathe which has a Furnas drum switch on it. If anyone could point me in the direction of success that would be jim dandy. Disregard the white and green wires just wires I put on to test it out.

The first thing to do is get a new reversing switch.
What you have is not safe to power a flash light.

No problem at all there. But how to wire it up is really what im looking for here.

Nathanscott2000 said:

No problem at all there. But how to wire it up is really what im looking for here.

Click to expand...

That is not "No Problem".
It's badly burnt and needs replacing.

Oops, did you mean it will be replaced?

When you replace that drum switch, the cover on the new one, on the inside will show a wiring diagram that should be self explanatory. Pay attention to the differences between single and three phase on the diagram. And as you can see on the motor wiring diagram,the drum switch will simply swap the blue and yellow leads for FWD and REV. Regards, Mike

Safe ???

It is NOT badly burnt, and DOES NOT need replacing...

My 1937 still has original drum switch, which looks about the same...

It as safe as brand new...

And I bet, works as well also... At most, a slight bend of a fixed contact arm needed..

See the HUGE air gap between contacts. It is not going to self start....

Drum switches are not as common as they used to be... They are a crude, full voltage AC switch... Always will be, and built like a tank...

A good TIG welder could build up the (TRIVIAL) wear on the main rotating contact block. Good old Romex will provide filler rod..

The fixed contacts look fine.. Believe it or not, filing them to look pretty, will actually reduce contact area, and shorten lifespan...

A modern 1/4 hp motor is BARELY adequate for that lathe. I would not even bother installing one.. Even though thats what they recommended in the 40's

Modern motors are of lighter/cheaper construction..

My 9 in, has had a 3/4 hp on it for years... Even drill presses that drill 1/2 in holes have 1/2 hp motors... You have even more friction with plain bearings, and countershaft..

And the main thing that differs from the old days.. Carbide tooling...

Here is one real good thread that may help

http://www.practicalmachinist.com/vb/south-bend-lathes/help-please-wiring-switch-motor-257832/



And this link here is even in the sticky's at the top of the forum but you have to dig a bit
Reversing and Repair of Electric Motors


I would say the guys are right about the 1/4hp motor will be weak for your lathe. Still more than likely when you get a bigger motor it will wire the same so it will help to get this one going. You may be ok when running in the lower speed ranges and with back gear.

Jess

This should work:



Basically, you have to extend motor terminal 4 and 5, and the blue and yellow wires out to the switch. L1 will be switched, L2 will bypass the switch. If the motor turns the opposite of what you want, switch the blue and yellow wires at the switch.

Oh, and you should clean and adjust the switch contacts.

allan

Ken-Bergen said:

The first thing to do is get a new reversing switch.
What you have is not safe to power a flash light.

Click to expand...

That switch shows signs of lots of sudden reversing. In a pinch, it could be repaired, but its a whole lot easier to just replace it.

Got it wired thanks to Kitno455's diagram. Your all gentlemen and scholars.

WHOA STOP..

If that is a Leeson 102889.00 there are MAJOR PROBLEMS..

Does it look like this???? : Leeson Fan and Blower Electric Motor — 1/4 HP | Electric Motors| Northern Tool + Equipment Campaigns&cm_pla=&cm_ite=leeson 102889&mkwid=en5sGDy8H&pcrid=1096244884&mt=e

"This Leeson 115V split-phase motor is designed for commercial duty air over fan motors for air circulators."

It looks like it might be an air over motor... ONLY SUITABLE FOR FAN USE. The fan blades cool the motor.

Next problem.. It is Split Phase, not a capacitor start, which will be needed for a hard starting machine tool like a lathe..........

Sure it will work, for a short while....

There is NO sudden reversing with a single phase motor. (not counting a brushed universal motor Like a hand drill)

Motor will merrily continue to spin the same direction...

Which is a good thing with a threaded spindle.

Nothing like plug reversing a 3 phase lathe, and watching the chuck unscrew, and head directly for your foot.. After making the lathe ways, look just a bit worse..............

Not likely with stock leather belts on a small threaded spindle SB, But possible...

And since ALL 9 inchers were threaded.......

Hope you didn't waste any money on a drum switch you never needed.
Doesn't need any adjusting or filing either. Should be good for another 50 years or more.

In 1976 I had occasion to work in a manufacturing facility that was built in 1937.The starters in the starter racks had copper contacts simelar to those in your drum switch.We were replacing the old starter racks with modern motor control centers in electrical rooms that were small.In order to remove a section of the old racks to set the first MCC,it became necessary to move circuits from one section to another.The starters that had been abandoned had contacts that looked like your burnt ones (550 volt 3 phase can do some arcing)I was able to get them back in service by filing them.Operations was very pleased that they didnt need to shut down.