Dc crane problem

Discussion in 'General Electronics Chat' started by docker, Jan 25, 2012.

  1. docker

    Thread Starter New Member

    Jan 25, 2012
    got a question,working on a 4 motor (2 sets) dc crane,you run each set and they run perfect,run both sets together and one set has 20 amps on armatures and other set is showing -40 amps,traced out all wiring,seems good and motors passed signature testing,no grounds and no shorted wiring, any thoughts???
  2. praondevou

    AAC Fanatic!

    Jul 9, 2011
    Please post a schematic.
  3. KJ6EAD

    Senior Member

    Apr 30, 2011
    You're talking about a dual vending crane for toys, candies and such?

    This sounds like a power supply problem. Either there is a shared supply that's incapable of supplying enough current or separate supplies that are bused togther and one is faulty.
  4. docker

    Thread Starter New Member

    Jan 25, 2012
    its a 250 ton hot metal crane,both pairs are electrically isolated from each other,(except for the feed) and gearboxes are connected so when 1 pair runs, the whle drive train runs, so pretty sure not mechanical