Industrial breakdown situation - can you help?

Discussion in 'General Electronics Chat' started by antiskeptic, Oct 27, 2010.

  1. antiskeptic

    Thread Starter New Member

    Oct 27, 2010
    Hi there,

    I've a production line come to a standstill due to an electronic problem - and our electrician is on holidays. I hope you can help.

    The problem lies in the dead display of a frequency AC drive. Either the drive itself is bust or there is no control voltage being supplied to it - it's just that we can't figure out from the drive instructions which are the control voltage terminals.

    Perhaps you could help? The terminal block diagram is on page 8 of the following PDF (sorry I can only supply the link to the pdf download)


  2. DigitalReaper


    Aug 7, 2010
    Pin 13 has a 0-10v input for speed control.

    In the supplied diagram a pot is used as an example, drawing its 10v and ground rails from pins 12 and 14 respectively. The specs on the pot are also on there (1k-10k, 2 watts).
  3. R!f@@

    AAC Fanatic!

    Apr 2, 2009
    U said dead display of the VFD.
    So u need to replace the VFD unit.

    I don't think u can fix the drive urself, since u need a lot of experience on how an AC drive works.
  4. antiskeptic

    Thread Starter New Member

    Oct 27, 2010
    I suppose the question is whether the power supply which runs the display is taken from the 3 phase AC supply (which is fine) - in which case the unit is broken. Or whether it's an external supply - in which case it's the external supply which might be the problem - not the unit itself.
  5. antiskeptic

    Thread Starter New Member

    Oct 27, 2010

    True. But that 10v supply is listed on the next page (p.9) as a drive supplied power source to drive an external pot - not an external power source to drive the control side of the inverter.

    Perhaps the inverter takes it's control side supply from the 3 phase AC supply - stepping it down and converting to DC?

    How would I tell?
  6. antiskeptic

    Thread Starter New Member

    Oct 27, 2010
    Resolution! (as such)

    It turns out that the control-side supply is indeed tapped off the mains 3-phase supply. Since that supply is in place, the conclusion is that the unit is bunched.

    Temporary bypass/botch activities have already taken place to workaround the problem and get production going again.

    Thanks for the input...
  7. GetDeviceInfo

    Senior Member

    Jun 7, 2009
    I haven't worked specifically with the powerflex 40, rather the 70/700, but when you apply power to the unit, irregardless of whats connected to the IO terminals, you should get a display.

    I would be checking that you have all your power phases available to the drive. Is it possible that a contactor has dropped out due to some othe control condition. Do you have schematics?
  8. Jaguarjoe

    Active Member

    Apr 7, 2010
    Did you call Allen Bradley/ Rockwell?
  9. thatoneguy

    AAC Fanatic!

    Feb 19, 2009
    Not much to do in these cases other than having a programmed standby for replacement, especially if costs run into 5 digits per minute of downtime.