Switch question for an 90's Unisaw

[andrew whicker]

The transformer was reading odd outputs (40v+) when the sticker on the transfer says 24. The momentary remote switch seems to be acting properly (N.O. and N.C.).

For a while, the motor would start after plugging the machine in and the motor would run at low speed. I let it run at low speed for a minute, it tripped my breaker.

Some friends and I were looking it over, trying to understand how it works (one of my friends used to diagnose locomotive electrical issues) and it started working flawlessly. However, we didn't actually touch anything. Yesterday, i tried starting it and it wouldn't start.

I think the solution is new magnetic switch to replace the old Unisaw components. Is there a reason for not doing this?

[Jeff Heath]

Something is certainly awry. If you don't have the diagnostic equipment to trouble shoot the starter you have, they are usually cheap enough to buy. Frequently $75 or less on the OWWM forum. I probably have 6 or 7 of them sitting in my rathole, from restorations. I buy them for future use at swap meets. You'll find one.

[Curt Harms]

The transformer was reading odd outputs (40v+) when the sticker on the transfer says 24. The momentary remote switch seems to be acting properly (N.O. and N.C.).

For a while, the motor would start after plugging the machine in and the motor would run at low speed. I let it run at low speed for a minute, it tripped my breaker.

Some friends and I were looking it over, trying to understand how it works (one of my friends used to diagnose locomotive electrical issues) and it started working flawlessly. However, we didn't actually touch anything. Yesterday, i tried starting it and it wouldn't start.

I think the solution is new magnetic switch to replace the old Unisaw components. Is there a reason for not doing this?

I think it depends on how concerned you are with authenticity. Some people treat Unisaws as collectibles which is fine. I have a G1023 with a Tian magnetic starter and it does what it's supposed to do. The difference between the paddle switches and magnetic switches is that magnetic switches include overload protection. If a motor is designed to work with a starter, I wouldn't bet on its having overload protection built in.

[Jeff Davies]

Forgive me if this is redundant.... I 'm gonna bet your low voltage circuit (LVC) relays are dusty. Not at the push button switch in front , but in back or where ever , are the high voltage switches . these are operated by elctro-magnets that are activated by the low voltage small switch in front .
Pull the cover off and blow the dust out of it with compressed air . Now I can't tell you to blow on them while 'hot ' and cycle them while blowing, but that is what I have done, to clear them out.... Yeah, Yeah, I was sitting in a tub of gasoline too...... just don't be stupid and become part of the circuit.
I reassemble these boxes with calking. It is amazing where the dust can migrate . Regards, J J Davies

[andrew whicker]

Yeah, I definitely want a magnetic switch. Was interested to find one with a paddle switch, but I guess that's asking for too much.

[andrew whicker]

I've blown out everything. I still need to figure out what the issue is.

[andrew whicker]

could I keep the magnetic switch 'on' full time and have a paddle switch control power to the switch? So in other words, have a paddle on the 220v line before the mag switch? I'm not sure if the mag switch can stay without power, since they are momentary switches.

[Dan Hahr]

Sounds to me like a capacitor issue.

Dan

[Curt Harms]

could I keep the magnetic switch 'on' full time and have a paddle switch control power to the switch? So in other words, have a paddle on the 220v line before the mag switch? I'm not sure if the mag switch can stay without power, since they are momentary switches.

I don't think you could add a paddle switch before a magnetic switch and expect it to stay on. The unpowered state of a table saw starter is "off" AFAIK. I guess you could put a paddle switch after the magnetic switch but I'm not sure what that would gain you beyond the ability to turn the saw off with a bump of your leg. People have hinged small vertical boards above a magnetic starter with a piece protruding so that when the wooden board is bumped it pushed the magnetic starter's "off" switch.

[Bob Vaughan]

I think like others do. The contacts are likely corroded or dirty. This is a very common problem when those switches get some age on them. Take the switch apart and clean the contacts. Air won't do it. Its likely your switch is a Furnas-made unit. Those units made for Delta had a little longer plunger than the standard Furnas plungers because of the push button design used by Delta.

Here's how to clean it.

http://owwm.org/viewtopic.php?t=32071

[andrew whicker]

Ooooo.

Thanks for the link

[andrew whicker]

That's an interesting idea. thanks

[andrew whicker]

A follow up for those of you on the edge of your seats with anticipation:

I temporarily wired up a new magnetic switch (bypassing the Delta magnetic switch entirely) and it starts and stops fine. The Delta transformer was giving odd voltages. I otherwise didn't dive into the Delta magnetic switch. I took apart the remote switch and cleaned the contacts (they weren't dirty) also.

cheers,