magnetic starter not working

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Forum topic by DFD posted 01-28-2013 02:15 PM 1275 views 0 times favorited 7 replies Add to Favorites Watch
View DFD's profile


1 post in 1967 days

01-28-2013 02:15 PM

Topic tags/keywords: magnetic starter table saw

I just purchased and transported a used table saw. Got it all set up, pressed red on the magnetic starter, and plugged it in. The dang motor started running! Ran over and pressed the stop button again, and it went off, but when I let go of the stop button, it started up again! I had to rush back to the breaker box to turn the current off.
Earlier, the machine started fine at the seller’s house. I may have banged the starter during transport—the bottom of the interior assembly appeared askew when I opened it up. Wiring looks professionally done, although red wiring does not follow the illustration in the manual (black, white, and green do).
It’s a 3 HP, 220V, single-phase.
Any suggestions?

7 replies so far

View ChrisK's profile


1972 posts in 3104 days

#1 posted 01-28-2013 02:38 PM

Check that the ON button is not stuck. Sounds like the STOP is opening the circuit to the starter coil but the ON is still engaged.

-- Chris K

View crank49's profile


4032 posts in 2993 days

#2 posted 01-28-2013 03:11 PM

Contacts must be stuck on the “ON” button.
If the case looks askew, it may be binding on the button.

Oops, I see that was already suggested while I was away from the computer..

View REO's profile


928 posts in 2096 days

#3 posted 01-28-2013 03:41 PM

try it with the cover off if it works properly take care reassembling andtryagain

View Loren's profile


10476 posts in 3670 days

#4 posted 01-28-2013 04:14 PM

Magnetic starters can get corrosion on the contacts. When
this happens the starter won’t stay in a position. That’s
one issue that can come up. The contacts can be
reconditioned with fine wet/dry sandpaper. Taking
apart the starter will probably be required.

Under power the magnets on one side of the switch
may be pulling harder (contacts in better condition)
one way that the other. I had this problem with
the starter on an old 3 phase machine. In my
case the motor would not stay on because the
springs in the starter were pulling stronger than
the “on” position magnets.

Also explore lubricating the moving starter parts with
graphite to make sure it is not binding.

View crank49's profile


4032 posts in 2993 days

#5 posted 01-28-2013 09:07 PM

Hold back on that graphite suggestion.

Graphite is carbon.
Carbon is a conductor.
Might be the equivalent of spraying powdered iron into the electrical works.

I’d rather lube it up with motor oil than graphite.
Actually they make lubricants specifically for these type devices.
But be careful, they usually contain silicone which is a no no in the finishing department.

View Grandpa's profile


3259 posts in 2698 days

#6 posted 01-28-2013 09:10 PM

LPS3 should work shouldn’t it??

View crank49's profile


4032 posts in 2993 days

#7 posted 01-28-2013 09:50 PM

Don’t see why not.

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