Magnetic chuck?

2 Responses to “Magnetic chuck?”

1. Comment by Nick F

   possible it’s a magnetic chuck with an on/off lever?

2. Comment by jimdempster

   First thing to do: with no power applied, check continuity through the magnetic chuck with an ohm meter. If there is no continuity between the power leads, there is a broken electrical connection that needs fixing. There should be no continuity to ground.

   Second thing to do: check the nameplate electrical rating to make sure you’re applying the correct voltage (110VAC, single phase). If the nameplate requires a different voltage, apply that. If no nameplate, you might want to check out the Rockwell website (if it is a Rockwell component; I suspect it isn’t, probably aftermarket so check out their website).

   One of the things to consider is that while the magnet might be able to operate on AC, the actual electrical current going through the chuck coils may be DC, so you need to rectify the current somehow. I’d look for some diodes or rectifiers inside the chuck and check those for proper operation – if they failed there would be no magnetic chucking even if you had it plugged into the wall. Failed diodes will fail the continuity test in step one.

   You probably have to remove the chuck to take it apart; you’d only do this if it failed the continuity check because you’ll need to regrind the surface of the chuck after reinstalling to make the chuck surface parallel.

   The other possibility is that external DC current needs to be supplied through some power supply that you don’t have; this is where the nameplate comes in handy telling you if you need DC or AC current.

   I would think you’d need an electrical current limiting device on the input side to the chuck (like a transformer) rather than running AC from the wall straight into the chuck – too much current would blow the circuit breaker or cause a fire. Be careful!