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About 8 or so years back, I had a massive problem with the wonky magnetic starter on my own Unisaw. I picked it up from a local high school shop and it had a strange magnetic starter assembly and a transformer that was a serious pain to sort out.

Folks on here gave me a lot of support and eventually I got it working... until there was enough fine dust in the air to screw up the contacts. After moving I pulled out all of the mag starter stuff and replaced it and the original switch with something like this: https://www.amazon.com/POWERTEC-714...&keywords=220v+starter&qid=1617764295&sr=8-19
it's worked pretty trouble free ever since. Recommend you upgrade and ensure the starter switch is sealed up tight from fine powder dust.
 

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Discussion Starter · #24 ·
About 8 or so years back, I had a massive problem with the wonky magnetic starter on my own Unisaw. I picked it up from a local high school shop and it had a strange magnetic starter assembly and a transformer that was a serious pain to sort out.

Folks on here gave me a lot of support and eventually I got it working... until there was enough fine dust in the air to screw up the contacts. After moving I pulled out all of the mag starter stuff and replaced it and the original switch with something like this: POWERTEC 71443 Single-Phase Magnetic Switch Box, 220/240V, 3 HP, 18-26 Amp, Heavy Duty, CSA Certified, multi color - - Amazon.com
it's worked pretty trouble free ever since. Recommend you upgrade and ensure the starter switch is sealed up tight from fine powder dust.
I had the same experience as you, the support I got from Rick was incredible. This place is a godsend and I plan on sticking around to help others with what I can.
 

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Jack of too many trades..
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I had the same experience as you, the support I got from Rick was incredible. This place is a godsend and I plan on sticking around to help others with what I can.
I've grown a lot as a woodworker with help from the folks on this site. it's one reason I try to contribute my meager knowledge and insight when I can.
 

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I've got a similar problem except there is no power to the on/off switch at all. Its got power to the transformer, specifically the common and the 230 tabs listed on the schematic, but nothing coming out. I'm less of an electrician than anybody who has commented here but I think I need a new transformer but not sure where to get it as the Google has failed me in finding a similarly specd transformer, specifically the .40kva rating. The saw did run when I purchased it. Any help would be appreciated. I did order the switch recommended in this thread.
430569
430570
 

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you have 2 easy checks. fuse for transformer power (circled blue) check continuity with power off
and motor overload (circled red) just push the black button, if it clicks that was it

before you power up the saw, check that the blade spins freely
report back with your findings

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Its got power to the transformer, specifically the common and the 230 tabs listed on the schematic, but nothing coming out.
Transformers rarely fail. So this statement caught my eye.

When you say there is no voltage at the output, the very first thing to come to mind is how you determined this. A common mistake that people make when using a voltmeter, is that they always put one probe on ground....THIS IS WRONG.

When measuring the voltage coming out of the transformer, put each probe to each output. You need to measure the voltage across the transformer. "Ground" has nothing to do with the circuit.
 

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A wealth of information on this page. The fuse has continuity and the reset button did not click.

I do NOT have any voltage across the 2 red tabs on bottom right of transformer.
 

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check for voltage between H3 and H6
check for voltage between X2 and both ends of the fuse
did you remove the fuse to check continuity?
 

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check for voltage between H3 and H6
check for voltage between X2 and both ends of the fuse
did you remove the fuse to check continuity?
I went through all the settings available and could not get it show voltage between h3 and h6. The wires in question show 120 volts when measured separately but 0 when measured across. As stated earlier, I'm not an electrician so is it possible I'm using the wrong tool to measure voltage?

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use the 500v setting, it should read 240v or there abouts
basically the H3 and H6 is a line voltage check to make sure you have 240v
start with basics and make sure the cord is wired correctly
 

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As advised I went back to the beginning and traced wires from the breaker box.
Circuit component Electronic component Electrical wiring Electronic engineering Electricity

I have 124 on each leg coming into the saw circled in yellow, 1 & 2 respectively.

I checked the switch thinking the red wire to the start switch would show some voltage.

Going up to the top right there is power going in via the Yellow circled wires but nothing coming out from the red circled wire which leads to the switch via the 2nd red circle in the lower right.

Should I replace what ever the contraption in the top right is?

Thank you.



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this is a most basic motor starter and wiring, but you need to follow basic logic and troubleshooting
what is the voltage between H3 and H6? this check confirms tight connections to the transformer. use the 500 setting on the volt meter
what is the voltage between X2 and both ends of the fuse?

there should be power between the black wire in the switch and X2, if you look at the wiring diagram and follow X1 off the fuse, the only connection is to the NC (normally closed) contact.
the contraption on the top left, circled in red, is the holding contact. from the white wire on the switch
 

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this is a most basic motor starter and wiring, but you need to follow basic logic and troubleshooting
what is the voltage between H3 and H6? this check confirms tight connections to the transformer. use the 500 setting on the volt meter
what is the voltage between X2 and both ends of the fuse?

there should be power between the black wire in the switch and X2, if you look at the wiring diagram and follow X1 off the fuse, the only connection is to the NC (normally closed) contact.
the contraption on the top left, circled in red, is the holding contact. from the white wire on the switch

H3 to H6 shows 0 at the 500 v setting on the multimeter.

From x2 to either end of the fuse also shows 0 on multimeter on the 500v setting

There is no voltage showing between the blackwire off the switch and x2

Thank you for your help and patience
 

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I have 124 on each leg coming into the saw circled in yellow, 1 & 2 respectively.
Nope. Stop measuring voltage to ground, EVER!!

You have both wires on your house wiring to the same phase. Shift the 2 circuit breakers either up or down 1 position. You should be getting 240 volts BETWEEN the the two wires you mentioned above.
 
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