Tek-Tips is the largest IT community on the Internet today!

Members share and learn making Tek-Tips Forums the best source of peer-reviewed technical information on the Internet!

Register Log in
  • Congratulations cowski on being selected by the Eng-Tips community for having the most helpful posts in the forums last week. Way to Go!

Recent content by jcbvet

  1. jcbvet

    DC Drive Control Problem

    All pots are Linear. I just replaced it with a new 5K Ohm 3 watt. Same issue. I can't imagine the commutator being dirty enough to cause this. There is a 10 Ohm ceramic resister in series with the wiper on this pot. I'm going to take a look at it this evening when the shift ends. It may be time...
  2. jcbvet

    DC Drive Control Problem

    Crowbar1, Ah ha moment. Thanks......
  3. jcbvet

    DC Drive Control Problem

    Ok, well maybe they aren't burning out. The range has changed. Instead of 0-100% on the speed dial, the pot operation is between 15% and 40%, so as you turn up the speed pot, nothing happens until it reaches 15% on the dial, then the drive responds. As you ramp up the speed, it will reach full...
  4. jcbvet

    DC Drive Control Problem

    This pot is used regularly for this machine. I get's adjusted from 0-25% every 5 or 10 minutes as part of a manual speed control for starting the process. Maybe we are just wearing the darn thing out. Could it be they just don't make them like they used to? this is a 2 watt pot, would getting...
  5. jcbvet

    Motor Stator failure

    That failure is an insulation failure. Starting at where the winding enters the stator stack. Large HP windings move a lot under inrush. there should have been some glass wrapping laced through the windings.to prevent the inrush torque on the windings. Maybe there wasn't thick enough slot paper.
  6. jcbvet

    Large motor efficiency loss on re-wind.

    Efficiency could change when the rewind changed the wire size to make it an easier wind. Converting one wire into two etc. to make the circular mills smaller to fit through the slot in the stator. If the motor isn't used on a VFD or a critical speed control, it may not make a difference.
  7. jcbvet

    Delta Bandsaw Runs Backwards

    If the centrifugal switch isn't closed when the rotor is put back into the end bell it will not start. If the centrifugal switch is fried together, it will not start, it will sit and hum, burn out the start windings. If the capacitor is bad, it will not start unless it is pushed. It looks like...
  8. jcbvet

    DC Drive Control Problem

    We have a very old DC drive (Dodge-Mishawaka Ind. 300A circa. 1970)that has started eating up the external Speed pots.. They sometimes last months, others only a few weeks. 1K 2 Watt potentiometers. There is a resister in series with the Speed pot. It's a ceramic 10 Ohm 1 Watt. Could this...
See more

Part and Inventory Search

Back
Top