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)

Cheers..


http://literature.rockwellautomatio...ets/search_results.hcst&ftx=&passedLangVal=EN

 

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).

 

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.

 

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.

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.

 

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).

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?

 

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...

 

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?

 

Did you call Allen Bradley/ Rockwell?

 

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.