Electricity IS smoke. Every electrical apparatus, cable etc. at the point of manufacture is filled with just the right amount of smoke to ensure satisfactory operation by internal circulation of the smoke around all parts of a circuit. If you let the smoke out, things stop working (QED).

Eddie

------ Original Message ------ From: "Glen Ruch via groups.io" <gw.ruch@...> To: SouthBendLathe@groups.io Sent: Tuesday, 31 Aug, 21 At 15:54 Subject: Re: [SouthBendLathe] Switch Smoke

I would also consider dirty contacts. If so the heat generated might melt the switch insulator and the contacts, or termination might be loose in the insulator.

Hope this helps

On 8/31/21 10:33 AM, G K via groups.io wrote:

Ray,

Thanks for the insight. The switch through arm was quite loose making eh switch operate sloppily (if that's a word). I'll tighten things up, replace the jumper. check a few terminals for shorts, and plug 'er back in.

Thanks again,

Greg

On Tuesday, August 31, 2021, 08:43:13 AM CDT, Ray De Jong via groups.io <dejongray@...> wrote:

The Jumper terminal screws may have been a bit loose and arcing occurred and the resulting heat build up probably fried the wire. I have replaced many receptacles that fried not only the lead-in conductor but also the inside of the outlet, all from contacts losing their tension an/or a loose connection

On Monday, August 30, 2021, 6:34:26 PM PDT, G K via groups.io <bug_hunter2000@...> wrote:

Working on the SB9 tonight, and smelled a little burn. Flipped the switch off. looked around and saw no issues. Flipped it back on and pop goes the breaker, and smoke from the switch. I believe the switch is the original (1942) drum switch. Unplugged it, and took the cover off the switch, and the jumper was fried. No idea why. I'm not an electrician, but can use a voltmeter. Suggested troubleshoot?

120 volt circuit. Furmas R44, 6-terminal switch, Dayton 3/4 hp motor.

I'm planning on pulling it apart tomorrow and look for any additional burned wires, but I do not believe I will find any from a cursory look. Then I'll wire a receptacle directly onto the motor to see if there are any issues there. If were good there, I will re-wire the switch and see what happens. Maybe some chips got inside and caused a short. Not sure. Any chance capacitor went back and caused the short? The only burn smell is in the proximity of the switch, but that could be where the smallest gauge wire (jumper) is located.

Thanks,

Greg