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View Full Version : This is the way NOT to do things!



cybor462
10-16-2007, 11:23 AM
You may have read my lathe motor went up in smoke. After checking it I found the run cap was totally melted. I tried to get one locally only to find they all were physically larger and would not fit in the housing.

I did not want to wait nor did I want another Chinese cap so I bought a US made and had to rig it up.

I know, this should not be this way but until I get time to do it different here is what I have. I know a recipe for disaster.

How would you guys do it? Using the US made cap.

http://mywebpages.comcast.net/cybor462/cap.jpg
http://mywebpages.comcast.net/cybor462/cap1.jpg

A.K. Boomer
10-16-2007, 11:28 AM
I would be concerned with the limit of cap. wiring that can be ran, also know for the most part you will be right there but the reason its under the cover is for fire prevention, keep an eye on er Kap...

cybor462
10-16-2007, 11:36 AM
I know and I do not like this. The one good thing is that this cap is metal bodied where the OEM was plastic.

Maybe build a metal box to mount it in? Run the wires in conduit or mount the metal box on the lathe. That would take care of fire watch.

The guy at the motor rebuild shop I bought the cap from told me to mount it the way I did. Said I could not get a proper size (physical) to fit unless I go Chinese and he said he could not get one.

I was also concerned about arcing as this one has top terminals and the OEM was direct wired internally.

tattoomike68
10-16-2007, 11:36 AM
All you need to do is make a good sheet metal housing and screw it onto the machine.

Do you know anyone with a little shear and box/pan brake? If not a trip to a junk yard and you might find a little housing that will work. Like an old PC power supply box.

Mike W
10-16-2007, 11:38 AM
Just find a larger box of some sort that the cap will fit into where it goes on the motor.

cybor462
10-16-2007, 11:45 AM
I think that will be the way to go, build a metal box. I am also concerned about exposed wiring at the motor end. They had the cap soldered (very poorly I may add) to the wires exiting the case. They have about 1" of wire exposed to solder to. I had to do my best and solder to them. I used an electronic bench gun so it would not overheat things too bad but they have the worst insulation and it got real soft and now I question it. I used shrink wrap as best I could but could not do much with the wires through the case. I forced some RTV into them to insulate as best as possible.

The proer way would be to remove the motor, open it up and wire it correctly. My fear is opening the motor. Not sure what problems I would cause as the import motor is not the highest quality. Not sure if just jarring things would not cause problems.

paulx
10-16-2007, 11:49 AM
That will work fine.

John Stevenson
10-16-2007, 01:42 PM
Punch two holes in an aerosol top, thread the wires in with knots on the inside to stop them pulling out and fasten to the motor with a big hose clip.
Seen many done this way.

.

lane
10-16-2007, 08:58 PM
Drink one beer . Cut top out of empty can . Bolt can to pecker head on motor. Insert cap. into can shorten the wires. If you feel like it paint can green.

JRouche
10-16-2007, 09:30 PM
I like it, makes for easy cap replacement.. I like Johns idea with the aerosol can the best. Funny how many solutions I find in the trash. Maybe why I am so reluctant to throw anything away. I'll just be dumpster divin later. LOL.. Should work fine. Heat shrink the terminal ends so you donít accidentally brush up against the mains. JRouche

darryl
10-17-2007, 03:00 AM
In many cases, what kills a part is heat from a poor connection. I would imagine that a fair amount of current flows through those wires under heavy loading. Do what you can to make the connections solid- peel back to expose fresh copper wire if you have to in order to get a properly soldered join. If there are spade lugs on the cap and those push-on connectors, make sure they are clean and tight, and that no heat is being developed at those points. Remember to unplug power after a test run, before fingering around those junctions. It's very unlikely that any charge will remain in the cap after power is disconnected since the cap is across a winding which will drain the charge rapidly. If you're worried about a shock, wear one of those cheap rubber gloves. That will insulate you from shock, but you'll still be able to feel excess heat if it's there.

From your photos it looks like maybe the gauge of the wire should be a bit larger- again you can check this after a test run and with power unplugged. If the wires are warm at all, the gauge is too small.

I have no problem with what you've done there, except I would have used some rubber covered wire instead, for better protection of the wire. Cab tire or extension cord material is what I would have used. 16 ga would be my choice, and I'd use some cable clamps of some kind to keep stresses off the wire ends- just those P shaped things that you clip around the wire and screw down.

speedy
10-17-2007, 05:56 AM
They had the cap soldered (very poorly I may add) to the wires exiting the case. They have about 1" of wire exposed to solder to. I had to do my best and solder to them. I used an electronic bench gun so it would not overheat things too bad but they have the worst insulation and it got real soft and now I question it. I used shrink wrap as best I could but could not do much with the wires through the case. I forced some RTV into them to insulate as best as possible.

When I am concerned about the isulation absorbing too much heat. I wrap some saturated wet cloth around, tie if I have to because I have only two hands :) , then go to it with the iron and solder. Remove the cloth when the solder has cooled .

cybor462
10-17-2007, 12:34 PM
When I am concerned about the isulation absorbing too much heat. I wrap some saturated wet cloth around, tie if I have to because I have only two hands :) , then go to it with the iron and solder. Remove the cloth when the solder has cooled .

I was lazy..to do that I would have had to remove the motor from the mount ( a real pain) and open it up. I think I may do that in the future if needed but if it works I will let it alone.

darryl..I used 14 ga wire. That is twice as heavy as the OEM so it would not give me any extra to go heavier.
I used to repair microwave ovens and one thing I learned was to discharge the cap before getting near it. An old screwdriver works well. Make sure the handle has no crack in and bridge the connectors.
I did that with this after I tested it (tested before I bagged it) and YES it was charged even after the machine was shut off and unplugged. Would have been a real eye opener.

lane...I only have bottle beer hate the can taste...how would I use the bottle? :D