Susan_in_SF

Wood and Metal Goddess
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Hi
I ran into a beautiful vintage power hacksaw. I have no pics of it now since, due to its weight, I had to remove the cast iron lathe-like legs off to load into my car. I bought this vintage NOS pushbutton switch for it. It is a Westinghouse model 1033369 E. I could not find any wiring info online. Before turning to a $100/hr electrician (San Francisco rate last time I hired one), I was hoping someone here can tell me how to wire this station. Here are some pics.
Thanks,
Susan s-l400 (36).jpg20180316_120940.jpg20180316_120955.jpg20180316_121007.jpg
 
That is a standard 3-wire push button station for motor starting, so good there. But..... You need a motor contactor to go along with it. What electrics are on your new hacksaw? Some pictures would be good when you are able.
 
Jim, you don't think that would be rated for direct wire as a switch? I'll bet the motor is 1/3 or 1/2 hp.
 
My inclination would be to save the switch for another use. Certainly a simple single pole switch would work for a power hacksaw.
 
You guys are no fun at all!

First it looks to be a "control" type setup in that it "controls" the device via another device.

As mentioned already they likely are momentary switches.

Can be confirmed with ohmmeter.

The stop is likely normally closed and the start is likely normally open.

2 general solutions...

Locate a magnetic starter and connect it or make one.

All that is really needed is a relay that can be wired as a latching relay so one with a 120 vac coil (if motor is 120 vac) would be easiest.

Before we go long in detail that is enough to get you thinking...

We picked up a box of contactor at a yard sale and in spare time convert our machines to mag start.

So far just table saw...Others to be done later.

Sent from my SAMSUNG-SGH-I337Z using Tapatalk
 
I'm a great fan of momentary switches with contactors / relays, they have the big advantage that if the power fails they switch off and don't come straight back on when it's restored, it's necessary for a damn fool (guess who...) to press the start button again.

To wire a contactor, you need a spare pair of normally-open contacts (often called "aux" contacts) from the coil's supply (can be live 120v with the right contactor) to one end of the coil, the start button (normally-open) wired across those contacts, the lamp between the non-supply side and 120v neutral, the stop (normally-closed) from the other end of the contactor coil back to neutral. This is the control wiring, you also need the 120v live and neutral on their own pairs of contacts, motor on the normally-open side of those.

Simples :)

Don't forget a fuse in the live ONLY - bad practice to fuse the neutral, if that side blows everything can be live although nothing works... Don't ask.

Dave H. (the other one)

Oh, another thing... Not so important on a power hacksaw, if you want to add emergency stops, they can go in one of the wires between the stop button and the contactor... a quick diagram may help?

Here goes...

Basic Contactor.png
Note the lamp's neutral connection doesn't go through the STOP or Emergency Stop switches - this means if it doesn't go but the lamp lights while you push START, one of the E-Stop switches is operated (open) and you know there's power to the machine - Stop and E-Stop are normally-closed, Start is normally-open.
 
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I just have to jump in here. If electricians really earn that much money out there, maybe I need to come out of retirement (spitting at 70) if they would have me. I'll work for somewhat less. All for a standard three wire control station yet.

A power hacksaw, assuming something for casual use, is going to be one HP or smaller. A fractional HP motor can be run on a large relay. A NEMA Size 00 starter would be best, but that can get real expensive real fast. BritSteel above has a good schematic, but there are some things I would do different in the States. First off, you must never switch the neutral. The NEC does not allow it here. A good way to get knocked on your butt, or worse........ I am going to talk at the grammar school level because you are talking of calling in a "pro" who will make it sound really difficult. It isn't to me. But for someone that doesn't know, well........

As an exercise, find a small relay. Find a 120 volt relay if you can. A "KHU17A11-120" is much too small for any motor. Will drive the light, though. The power plug, US standard, will have a wide slot, a narrow slot, and a round(ish) hole. The wide slot is the neutral, at ground potential.(theoreticly) The narrow slot is the "hot" lead and will sit you on your butt if you touch it. Even dry.....

Looking at the switch, the black button is start. Find the two connections for a "normally open" contact. The red button is "stop" and you will find a set of terminals for a "normally closed" contact. It looks like a very old Allen-Bradley switch, a nice one it is too. Very clean as well. In a steel mill parts system, they don't look that good even when they're new. The dust gets inside the boxes.

Run a wire from the line side of a plug, the narrow finger, to the stop switch. Another wire from the other side of the stop switch to one side of the start switch. Later, there will be a second wire here. From the other side of the start switch, a wire to one side of the coil of the relay. The other side of the relay then connects to neutral, the wide finger of the plug. When this is powered up, the relay should come on as long as you hold down the start switch. Remember to unplug it at this point.

Now, on the relay find a pair of contacts that are normally open when the relay is off. One of those will connect to the line side of the coil, where the push buttons are connected. The other side of that contact will connect to the short wire between the stop and start switch. The place I had said another wire would connect later. When you plug it in this time, pressing and releasing the start button should cause the relay to pick up and stay on, until you press the stop button. If it chatters, you got the buttons crossed up. No biggie. If you got the wire from the contact to the wrong terminal, it'll just blow the fuse. Lots of "spitzenpoppen und crackenpoppen". Again, no biggie........

If all you can find are 12 or 24 volt relays, it will still work. Just get a doorbell transformer to do the hook-up. The motor will likely be 120 volts, possibly 240 volts. Try to match the relay to the motor if you can. It isn't vital, but makes things a lot easier. Again, the best bet is a NEMA Size 00 contactor. The used price may make you change your mind about a simple ON-OFF switch.

Depending on where and when the machine was used, it may have a low voltage control system. If that is the case, the lamp will explode on 120 volts. Best just leave it off for now. I would highly recommend 16 AWG THHN wire for the hook-ups. It is available at any home center, hopefully in short pieces. And that gets into conduit and some other subjects. I am going to include a link, although it doesn't cover such basic wiring as this. Look just below "Stuff worth looking at" for "Home Shop Electrics". http://www.hudsontelcom.com/ Reading this may give a little insight into the subject. Feel free to contact me if this really is where you want to go.

Bill Hudson​
 
I'm a great fan of momentary switches with contactors / relays,

View attachment 262597
Note the lamp's neutral connection doesn't go through the STOP or Emergency Stop switches - this means if it doesn't go but the lamp lights while you push START, one of the E-Stop switches is operated (open) and you know there's power to the machine - Stop and E-Stop are normally-closed, Start is normally-open.

That diagram is for a 220V motor, where you have two HOT lines; the 120V motor circuit is slightly simpler, and is depicted here
<http://www.how-to-wire-it.com/how-to-wire-a-relay.html>
but the diagram is a little... odd. The circle "MCR" is an AC relay (120VAC coil) winding, the parallel lines "MCR" are NO relay contacts,
and the 'lamp' item depicts both a pilot lamp, and the 120 VAC motor being controlled...
Note carefully the STOP button has NC (normally closed, it conducts until you press the button),
and the START button has NO (normally open, it conducts only when you press the button) contacts; you'll
want to check that those are constructed as expected.
 
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