recurring motor start failure

[Lynn Kasdorf]

I have a problem with the motor on my dust collection system. Periodically, it gets to where it will not start. When I apply power, the motor just hums.

Every time it has done this in the past (about 3 times), I can resolve it by taking the back off the motor to revel the centrifugal starter switch, burnishing the contacts and blowing out any dust, and reassembling.

It is a good quality motor- a Century 3hp 3450 single phase, and was brand new about 2 years ago. The motor runs a 15" blower in push mode on a huge cyclone. This is located in the attic of my shop. Currently, the outlet from the top of the cyclone (fine dust) just blows into the attic. So maybe this dust is getting into the contacts?

Maybe I should arrange to seal the openings around the start switch area of the motor, without causing it to overheat?

Maybe this summer I'll either duct that fine dust outside, or get some filters and send the air back to the shop. I've not bothered to do this because the shop building is SOOO drafty, that it is nearly impossible to heat anyway, so I'm not worried about heat loss through the DC.

[Paul Kunkel]

Originally posted by Lynn Kasdorf

Every time it has done this in the past (about 3 times), I can resolve it by taking the back off the motor to revel the centrifugal starter switch, burnishing the contacts and blowing out any dust, and reassembling.

Currently, the outlet from the top of the cyclone (fine dust) just blows into the attic. So maybe this dust is getting into the contacts?

Maybe I should arrange to seal the openings around the start switch area of the motor, without causing it to overheat?

Maybe this summer I'll either duct that fine dust outside, or get some filters and send the air back to the shop. I've not bothered to do this because the shop building is SOOO drafty, that it is nearly impossible to heat anyway, so I'm not worried about heat loss through the DC. [/B]
Lynn, i think you know what the problem is. get that dust outside, filter it, or at least for a while protect the motor with .....maybe a box made of furnace filters. How can you just blow the dust to the attic? Doesn't it filter down to the shop? Gads!:confused:

[Steve Clardy]

I have a 1 hp and a 1 1/2 hp that likes to also collect dust on the starter switchs. Seems the dust will dry out or take off the light grease on them and then they hang and will not start, just hum.
I took a piece of foam filter that is used on the front of AC windows units and wrapped around the air vent holes, taping it on. Sure cuts down on the dust and problems. Has not seemed to heat up the motors more than what they normally do.
Steve



I am editing this after reading Bobs Reply. My fix is not the sure cure but it has worked for me. You have to clean the foam filters OFTEN. I do agree with Bob and Paul, get rid of the dust problem by venting the dust somewhere else, outside, bag, etc.
Hope you get problem taken care of. Steve

[Alan Tolchinsky]

I check is to turn on the motor and if it doesn't start, I try to help it a little. This can be very dangerous so be careful. I use a stick or something, never my fingers. I just give it a little push. If the motor starts with this method, it's almost for sure the starter capacitor. Good luck. Alan in Md.

[Bob Lasley]

Lynn,

As Paul said, it sounds like the dust is your main enemy and his advice to get rid of the dust outside sounds like the best solution. Do not block the air flow through the motor as this will cause motor failure sooner or later. Though it sounds like Steve is having success with foam, I would be cautious. Even running a motor slightly over its design temperature for long periods of time will cause it to give up the ghost prematurely.

One tip for burnishing contacts, use a pencil eraser.

Good luck,
Bob

[Kevin Gerstenecker]

Contact switches are notorious for being non dust friendly. From day one, when I put my Dust Collector in service, I installed a switched Recepticle. The contact switch that came with the DC Unit remains on at all times. My DC is 220V, so I obtained the proper 220V Recepticle, and a Single Pole Switch rated for the proper voltage and wired it up. Seeing how my Table Saw is basically in the center of my shop space, I placed the switch on the ceiling near the Table Saw. When I want to crank up the DC, I am always only a few steps away from the switch. This works out well for me and my shop setup. (I made sure I did this before I even assembled the DC Unit and put it in service, because I knew that it would never get done unless I did it that way!) ;) Just another idea......................

[Lynn Kasdorf]

Kevin,
The switch contacts that fail are inside the motor. They supply curret to the start coils when the motor is stopped and cut out after it spins up. You can't avoid them.

For controlling my system, I have an x-10 lamp module powering a very heavy duty 220 contactor. I carry around a little x-10 remote clipped to my belt while in the shop. It has on/off for 2 x-10 channels, so one is for the dust collector, and the 2nd is for my shop air cleaner (whenever I get around to building it!). This works well.

One caveat- I wired the outlet that the x-10 module is plugged into such that it is only powered when the shop lights are on. It is possible for gremlins to get on the power line and trigger things. It would be a bummer for the big 3hp DC to come on at 3am and run all night until I discovered it the next day...

LK