Need help wiring drum switch.

markba633csi said:
Mike: it might help to think of a cap as a sphere with a rubber diaphram across the middle. Pulsations of air or water on one side
will give equal pulses on the other but no actual transfer of air or water will occur.
Caps are like a conductor for AC (depending on the value and frequency). This is true for all caps but motor caps are specially made to withstand AC.
The store and release action for DC takes time which is what gives the phase shift for AC.
Mark
ps Tesla was way ahead of his time!
Click to expand...
Hi Mark,
thank you for the information
 
I'll add that the magnitude of the DC left in a capacitor that's in an AC circuit like the Start capacitor depends upon where in its sinusoidal cycle the line voltage was at the instant that the switch was opened. And also depends upon what else is still connected in the now OFF motor. If the motor is wired internally to run in only one direction and is being controlled by a single external ON-OFF switch, as soon as the motor slows back down enough to close the centrifugal switch, the capacitor will quickly be discharged through the now series connected start and run windings. So there is no potential shock hazard if you turn the motor off, unplug the line cord, and immediately open up the motor and start fiddling with the wiring. But if the motor is wired to be reversable and connected to most drum switches, neither end of the start circuit is connected to anything when OFF. So if the motor hasn't been OFF for a considerable length of time (dependent upon how good the capacitor is). you may get quite a jolt if you touch both capacitor terminals. The quickest way to guarantee that the capacitor is discharged is to unplug the line cord and then put the drum switch in either FWD or REV for a few seconds. But don't leave it there because Murphy will probably guarantee that you don't remember to put it back to OFF before you plug the line cord back in later. :chagrin:
 
Good points Robert, plenty of ways to get hurt with machinery- cut, maimed, electrocuted, your choice.
Be careful out there folks. Live to play another day. Discharge large capacitors with an insulated screwdriver before handling.
Mark S.
 
Last edited:
Clif did you get your wiring issues straightened out? This thread got a little sidetracked talking about capacitors...
Mark
 
No, but not because I can't, got sidetracked with very bad spindle run out, visible to my eye with 3" drill rod out of the chuck.

Had to order new spindle from Clausing and bearings from fleabay. When that is done, IE when the arctic goes back to the arctic and leaves us poor souls in Kentucky alone, I hope to get right on it. Right now my shop seems more like a walk in freezer than a work shop.
 
It's cold here too, I have this tiny heater that heats about a 2 cubic foot area so as long as I don't move from that spot I can work LOL
 
You must log in or register to reply here.
Back
Top