south bend lathe motor switch - anybody have a schematic?

What kind of switch is it, a three pole, center off, three postion drum controller? That is typically what sb shipped with their machines as a rule.

Jim

================================================== please reply to: JRR(zero) at yktvmv (dot) vnet (dot) ibm (dot) com ==================================================

I have the SB Form 645-LOXM--4-'46 Helpful hints on wiring which I will attempt to post in the drop box Gerry :-)} London, Canada

"Joe Comunale" wrote . It smokes in reverse. Does that mean it sucks ambient smoke in to the motor? Might be useful in a crowded room. ;-) Tom

Hopefully they should appear shortly as: SB_Form.............. Gerry :-)} London, Canada

The most common types seem to be six terminal switches, eight terminal switches, and nine terminal switches.

Six seems to be common, and of these there are two types which look the same but are wired differently, the ones that cross the contacts closest to the handle to reverse, and the ones that rotate them from across to along the axis. If you are lucky, you'll have a schematic glued inside the cover of your switch.

For a single phase 220 motor, use the straight through terminals to operate the start winding, and the reversing terminals to reverse direction of the run windings. This allows you to avoid wiring "hot" straight through to the motor, where a short or bad ground would allow it to keep running even with the switch off. I got the idea for this from some previous RCM poster who I cannot properly credit without spending a lot of time digging back through archived posts.

For my lathe, I ended up with this for a 110/220 reversing motor, set for 220:

/ +--o o--||--+ 3 | 3 S | 3 | +-----+ | | | +----------------+ 3 | | | 3 M2 | | o o---- L2 3 | | +-----o | o o-+ | | | | +-----+ +---o o---- L1 3 | 3 M1 | 3 | +---------------------+

Where S is the start winding, with capacitor and centrifugal switch, M1 and M2 are the run windings, and L1 and L2 are the

220 lines coming in.

This is with a switch which operates this way:

Fwd Off Rev o--o o o o o | | o--o o o o o

o--o o o o--o

Note the jumper on the bottom left on the circuit above.

For the type of six-terminal switch that crosses the top two sets instead of "turning" them, the jumper would go from the left side of the bottom contacts to the right side of the middle set, and the output to the bottom of the run windings would come from the left of the middle set. Also note that my use of left-right- top-bottom are from the reference point of the schematic, and your switch may be mounted differently. Also note that the green safety ground isn't shown, but gets tied to the line, switchbox, and motor housing straight through, so you'll actually need 4 wires from the switch to the motor.

And lastly, your motor may be set up differently as well.

A wander through google groups looking for "metalworking drum switch" will get you a bunch of info for the variants.

But anyway, hope that helps. --Glenn Lyford

One thing to check is the block which the wires hook to. Mine had the screws loosen up and the reverse position eat up the contacts with each activation until it quit all together. I have South Bends Original paper work for the various switches and how to wire them to a particle motor type. I'll fire up the scanner a see if it can pick up the details.

Regards

Jim Vrzal Holiday,Fl.

Joe Comunale wrote:

Try the following links:

I'll try to keep these here as long as possible. Copy on to your own media for future reference or move to a more permanent web host.

Regards

Jim Vrzal Holiday,FL.

Mawdeeb wrote:

Because the start winding in a 240 volt configuratin is frequently tied to the center of the two run windings (dual voltage motor) this is easier to implement than the same setup for 120 volts. See:

The 240 volt version has one fewer wire from the motor to the switch, then the 120.

Jim

================================================== please reply to: JRR(zero) at yktvmv (dot) vnet (dot) ibm (dot) com ==================================================

The first half seems to have arrived OK but I can't seem to get outlook to move the second half. Gerry :-)} London, Canada

Success at last! Gerry :-)} London, Canada

You can probably get then from industrial electrical suppliers, or from places like MSC or Grainger.

I picked up a spare from an eBay auction -- though it is of the format more often found on Bridgeport spindle motors (bar knob, instead of a lever shaft with a round knob at the end, but electrically, it still works the same.

Cutler-Hammer is one of the many brands out there, I think that Allen Bradley is another, or at least used to be.

But if you wanted to try your had at repairing the original switch, you might be able to machine a good terminal block to fit out of Delrin. The cover is a different matter, and perhaps a more serious one.

Good Luck, DoN.

I actually found it cheaper to buy a small vfd for my mill than replace the 2-speed 3 phase switch that was broken.

There are several nice ones on Ebay right now.

Bob AZ