Belt sander: Smoke escape!

Hi people,
I have an old HF 4" x 36" belt sander that has provided probably 12 years of reliable service. This afternoon, just when I really needed
it, smoke escaped from the switch at turn on.
The motor and everything else works fine but the switch is mushy and smelly.
This is an older unit and does NOT have a cap-can on the outside of the motor. Instead it has a small device with a coil of quite heavy copper and a black bakelite surroundings. I assume this is some sort of delay for rotation direction at start up.
I thought I'd just buy another one but even HF want $70-bucks and a little out of my league at the moment. Can someone please tell me how to wire a switch into this thing?
I think the little coil and bakalite thing are OK as the smoke came out of the switch itself and now it feels like there is nothing inside the switch..
I have a picture of the setup but not sure where to post it.
Dave
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Dave, I can't do that wrote:

Does it look like: http://www.harborfreight.com/manuals/93000-93999/93981.pdf
You could order a replacement switch: 1-800-444-3353
Prepare to wait ~30 - 45 days.
--Winston
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Dave, I can't do that wrote:
(...)

http://www.metalworking.com/dropbox.html
--Winston
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
To check out your switch theory, remove the remains of the switch, tie the two wires to the switch together, see if the unit starts up and runs normally. If that works you can order the parts from HF (use the new model number, the switch is pretty much a universal fit) or you can replace the switch with an aluminum plate and a heavy duty toggle switch. You want a SPST switch rated at least 10 amps, 20 amps would be better for a motor circuit.
Dave, I can't do that wrote:

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Hi Roy and others,
Thanks for the replies, but I had already checked HF's manual. I mentioned the NO cap-can as this is not a cap start motor. The switch HF shows is a simple two wire thing that I could easily manage to fudge around.
I have uploaded the pic to the drop box and you can see the switch has 4 connectors to integrate the coil thing into the circuit.
The main lead at the bottom is the power lead coming in and the Blue, Brown, Black and Ground lead goes to the motor.
The top two terminals on the switch (Red and Black) are bolted to the switch body so I assume they are carrying big current, the bottom two (White and Black) are riveted.
Unless I can get some other information I will assume that the Black/ Black make contact and the White/Red but can't be sure as the switch is fried totally.
Dave
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
OK, replying to my own postings.

I guess the switch had some different internal wiring. I plugged in a 10A DPDT switch I had lying around. The lights dimmed the motor ran. I put a clip-on meter and it was drawing 18+ Amps! Hasty turn off as a wisp of smoke curled out of the back of the motor.
looks like a scrap job to me unless I can find a cap start motor to fit in the available space.
Dave
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Mon, 18 Feb 2008 08:10:13 -0800 (PST), "Dave, I can't do that"

What you have there is a current activated relay which energizes the start winding on turn-on, then, once the motor is turning, the run winding current decreases to the point where the solenoid releases, disconnecting the start winding; this relay appears to be combined with the on/off switch. These relays are commonly found on sealed unit refrigeration compressors where it is not convenient to use a mechanically actuated start switch. Gerry :-)} London, Canada
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Mon, 18 Feb 2008 20:00:52 -0500, Gerald Miller

You just might get away with separate components, go see your appliance parts shop. Gerry :-)} London, Canada
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Thanks Gerald,
All a little too late, as you suggested, I think there was something in the switch that went with the relay. When I tried a conventional DPDT switch, got 18 Amp draw to the motor and shortly thereafter, more smoke. Ahh well. It served it's life well.
In fact I bought this at a HF sidewalk sale the used to have twice a year at Thousand Oaks. It had dropped-damage and I got it for about 15- bucks as I recall. I also bought one of the 4-1/2" x 7" bandsaws with drop-damage for 50-bucks, and it still goes today. It must have done 5,000 hours and still it keeps on keeping on.
So much for those HF knockers, some of their stuff is good, not all, but some.
Thanks for the suggestions anyway.
Dave
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

    It might not be dead yet -- a short bit of smoke from the windings is not always a sign of it dying -- though if you let it run too long, it will die.
    Two possibilities:
1)    Bearings or drag somewhere in the mechanism, so the motor is     having to work a lot harder than normal.
2)    As someone else mentioned, a current relay which is supposed to     switch off a start winding of some form is not working -- welded     contacts or debris (swarf) keeping the armature from moving to     break the circuit.
    But -- it might be time to replace it anyway.
    Good Luck,         DoN.
--
Email: < snipped-for-privacy@d-and-d.com> | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Thanks Don,
The motor spins freely, I suspect the 18A problem was something to do with the switch/Relay combo. Maybe using just the start winding when I wired in a conventional switch.
The motor works fine if I just connect direct to the two main wires, it is just that I can't guarantee direction. Not all that good for a belt sander. The motor obviously does not have a centrifgual start-switch so I can't just add a start cap.
Perhaps you are right, time to replace it. Bummer. The best 15-bucks I ever spent.
Dave
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

    Was the original switch provided with more than one pair of terminals? Is there a mechanical linkage to the relay? If neither is the case, I suspect that it is a problem with the relay itself. Either welded contacts or a build-up of sandings to keep the armature from moving, in which case it is applying power to the start winding full time -- or never.

    So -- dig into the relay and see what isn't working there.

    Worth a try with the relay at least.
    Good Luck,         DoN.
--
Email: < snipped-for-privacy@d-and-d.com> | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Polytechforum.com is a website by engineers for engineers. It is not affiliated with any of manufacturers or vendors discussed here. All logos and trade names are the property of their respective owners.