When I hit the Start button on my Unisaw, it gave a grunt, the blade started to turn and that was it. No further action when I hit the Off and then the On. The Breaker is not tripped.
Any ideas before I call an electritian – $$$?
Frosty
I’ve never had any problems with the saw prior to this and my bandsaw and jointer worked fine to prep the material for sawing.
Replies
Hi Frosty ,
Just for the heck of it I would check the wire ends in the plug and the motor connections .
I know you said the breaker is not tripped but sometimes they go bad , is there any other outlets on this circuit or can you plug another tool into it to eliminate the breaker box and circuit .
I had a similar happening with my Unisaw many years ago and the capacitor was at fault , it is possible the motor is burnt out as well . Sounds more like capacitor I hope .
good luck dusty
Dusty & DickWow! The response time is amazing.No, the saw is not new - about 5 years old.I tried another outlet which I know is hot. Still does not start.I rolled the blade backwards; no resistance; still did not start.I'll get into the connections tomorrow and will let you know.How do I check the capacitor?Frosty
J,Before you check the capacitor, open the box on the back of the saw, if you see some contacts that are partially burned out (they should be right in front of you) that's your problem, quite an easy fix.C.
Also Frosty , plug another tool into the outlet the saw was in , sometimes receptacles go bad as well as plugs .
dusty
Unplug the saw and try to rotate the blade by pushing it backwards with a 2-3 ft piece of 2x4.
If it turns try to rotate it almost a full turn a little at a time. Plug it back in and try to start it again. Is this a new saw?
Is there a reset button on the motor? Look around, it could be a rubber covered button or a red one on the end. Those are capacitor motors and that can need replacement.
Beat it to fit / Paint it to match
First we need to know if it has a magnetic starter switch, if it does it is most likely that the problem is there. Search Knots for that--it has come up before, sometimes it is just an adjustment or cleaning of the the relay.
Edward
Heck, it is most likely the switch even if it is not the magnetic kind.
Take your air chuck and blow the #%^# out of it.
Have you tried calling Delta and talking with a technician?
My understanding is these motors have two sets of windings, start and run. An analogy may be to compare it to a manual transmission, the start windings are first gear; the run, 4th gear.
If you look at a schematic http://www.lmphotonics.com/single_phase_m.htm you will see that the start winding has a Start switch wired in series. When the motor is at rest, the switch is closed. When you turn the power switch on, current flows through the start windings and the switch. When the motor gets up to speed, the start switch opens up (mechanically via centrifugal force). At this time the run windings keep the motor running, hence the name. (I works a little different with a magnetic starter switch, but I think you get the idea.)
I suspect that your start switch (either inside the motor or within your magnetic starter) is open when it needs to be closed. The grunt you hear is power being applied to the run windings, but not the start windings. (Think of it as using a car with a manual transmission, it's tough to start the car rolling from a dead stop in third gear)
If you want to check the capacitor, you can do it with an ohm meter. The meter should appear to "charge up" by starting at a low resistance reading climbing towards to infinity. make sure the capacitor is not connected to the motor during testing.
Disclaimer: Now this is a general description on my understanding on how this works, so use it with a grain of salt.
Try spinning the blade by hand, and turn on the power while it is still spinning. If it is spinning fast enough, and if the problem is in the start circuit it should take off, and then come up to speed.
My first guess would be the centrifugal start switch isn't closing on spin down, then the capacitor. Mechanical things have a lot higher failure rate than electrical ones.
If you had burned a winding, you would have smelled it.
The switch was the cause of no-start. Going through a decision tree I found I had power to the top half switch but the saw still would not start. I called my local "tool store"; (great people) they said to bring the switch in and they would check it out. As I was removing it, the white wire fell from the bottom lug, burned off! No master diagnostician needed now.I went to see if I needed a new switch - found the Delta price was $150.00 !!! Quickly decided that I would try to resurrect the lug on the current switch. An electrical supply company GAVE me a new screw (I bought a $5 fancy screwdriver as a show of appreciation) and I'll reinstall the switch this afternoon. If the switch does not work, the tool people found that a Jet switch will cost $60.00.Keep your fingers crossed - and MANY thanks for the prompt and helpful responses.Frosty
Grizzly has nice magnetic switches for a good price. I like them better than the one that came on my Unisaw. Match the switch with the HP of your motor.
Life is what happens to you when you're making other plans .
Thanks - I'll check them out IF my good luck does not hold out this afternoon.Frosty
You left a couple of words out:
"Try spinning the blade by hand, and turn on the power while it is still spinning. If it is spinning fast enough, and if the problem is in the start circuit it should take off YOUR FINGERS, and then come up to speed. "
Scary advice.
Guys, I guess I was wrong in assuming people are brite enough to know you spin, it and while it is coasting, hit the power. However, I will accede that not everyone is in fact that brite, and it could be dangerous.
If you are able to spin the blade on a Unisaw more than half a revolution of the blade, either you are tremendously strong, the belts are disconnected or the blade is loose on the arbor. Maybe not dangerous advice, but totally useless.------------------------------------
"The West won the world not by the superiority of its ideas or values or religion but rather by its superiority in applying organized violence. Westerners often forget this fact, non-Westerners never do."---------------Samuel P. Huntington
My Lucky Day!I was able to save the "burned" lug components, reassembled the switch and heard a glorious sound when I hit the "GO-button".All is well in Ann Arbor and maybe I'll apply the money I didn't spend on a combo jointer/planer.Thanks for the help.Frosty
Why was the connection burned? The usual reason is a loose terminal screw/nut/ connector.
That is why it is useful to regularly open switch/control boxes to remove any dust, visually inspect AND check tightness of all terminals.
Well run factories do it as part of electrical maintenance contract (at least those that I knew of) and so should home woodworms do it.
You lives and learns.Philip Marcou
Thanks. I have.Frosty
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