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Discussion Starter · #1 ·
Purchased an '86 Delta Unisaw from a shop that moved locations. Originally it was wired directly into the wall, and then they moved they put a plug on it and found it no longer worked.

It has a Leeson 4hp single phase motor, but after looking at the panel I see it was originally designed for a 3 phase motor.

I put a 220 plug on it and connected it to an outlet at my ranch (I have not verified it's actually 220 despite the outlet - unsure if that is a likely problem or not), but was unable to get electricity past the magnetic switch and into the actual on/off switch. Frusterated, I purchased this:


Hooked it up today and could not get it to turn on unless I manually engaged the magnetic switch inside (when I manually engaged the switch on the original panel it did nothing, for whatever that is worth).

I wired the motor directly to the 220 and it turns on, but when I put wood through the new blade it would cut and then bind. I feel like a 4hp motor should have way more power than this.

I'm at a loss. I don't know how to better diagnose this problem. Would really appreciate any help you guys could offer.
 

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My process on this is start with the source and work downhill -

1) verify the voltage
2) verify motor set up correctly
3) wire the switch directly to motor
4) check capacitors
5) check motor for obvious damage

If the mag switch is isn’t working I’m suspicious it’s not getting 220V.

Does it have a 220 plug on it? That’s a big clue about whether the previous owner knew what he was doing. From your description, I can’t deduce what the original set up could have been. The machine was obviously 3 phase and I can’t figure out why they motor would be wired into that.

I would take the cover off and check the wiring on the motor - not always easy to do 😳. If someone was in there it could be messed up.

I’m not familiar enough with magnetic switches to know whether they won’t work if the wiring downstream is incorrect. The first thing I would do there is bypass the “panel” and wire the switch directly to the motor. I’m pretty sure the panel you are referring to is related to the original 3 phase motor.

There are two types of capacitors, run and start. If the wrong kind of voltage or not enough voltage goes to them, they can be ruined (I know this from personal experience). Sometimes easy to check, sometimes not (swollen, leaking gooey stuff). But cheap enough to replace.

If it‘s getting the right juice and the capacitors are good it would have to be the motor itself.

You’ll get good advice from others. I’d be interested to know what happens when a 220V motor gets 110V to it.

Pics always help!
 

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Discussion Starter · #3 ·
Thank you for the reply, Robert. I’m at work the next 72 hours but will try to get photos when I get off duty. I will also take my multimeter and confirm it is 220.

I did bypass the panel and wired the motor directly. It started no problem, but seemed very weak. When I put some scrap wood through it it seemed to have trouble cutting and eventually would bind.
 

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Sounds like you're trying to operate a 240V motor from a 120V source rather than 240V. In that situation the motor will take twice as long to start, have about half the torque, and draw about twice as much current as it should (very rough numbers here) and of course the magnetic switch won't work. The big problem is the current. It can quickly overheat the motor to the point of smoking. Feed the motor 240V before turning it on again.
 

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although it could be a "weak motor", my guess is that something is wrong in the wiring. suggest you get a person knowledgeable in electricity to look at it for you.

swapping in a single phase motor for a 3 phase is doable, esp when the magnetic starter is replaced. but must be done correctly. what wiring schematic did you follow?
 

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Using logic. . . .
The saw worked in the old location.
The saw does not work in the new location.

There is nothing wrong with the saw. The problem is most likely in the new electrical power.
Lets start there.
° What does the new outlet look like? Does it look like a normal outlet? If it does the circuit is more than likely 120 volt, single phase. A big problem for the Unisaw.
° When you put the new plug on, how many wires and what color? It should be 4 wires, Black, Red, White and Green.
° If there is a fifth and blue wire, your saw is three phase. Unlikely if the saw was last used in a home shop.
 
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