ABB ACH550 HVAC speed drive wouldn't turn back on.

[ddcbacnet]

Hello everyone,

after major renovation speed drives on three floors of high-rise building wouldn't turn on.

Is there anything that I don't know? Is there a trick on how to start them after long shut-down?

They have been down for about 2 months and now they are acting as if there was no power to them.
Screen is completely blank, no sounds of cooling fan, clicking of relays or charging capacitor.
I have checked all wiring and voltage levels inside and outside the speed drive, and looked through user's manual.
I thought if you turn the on-off handle on, screen should lit and I should be able to run the motor in hand even if my controls are down.

Have anyone else stumped on it?

[GT Jets]

Hello everyone,

after major renovation speed drives on three floors of high-rise building wouldn't turn on.

Is there anything that I don't know? Is there a trick on how to start them after long shut-down?

They have been down for about 2 months and now they are acting as if there was no power to them.
Screen is completely blank, no sounds of cooling fan, clicking of relays or charging capacitor.
I have checked all wiring and voltage levels inside and outside the speed drive, and looked through user's manual.
I thought if you turn the on-off handle on, screen should lit and I should be able to run the motor in hand even if my controls are down.

Have anyone else stumped on it?

Be careful with variable speed drives, think of them like a 600 volt battery that wants to shock the snot out of you.

It sounds to me like your drives have an integral bypass. If they do, there is a chance they may have a configuration problem.

My recommendation would be to place a service call with your local ABB rep and have them perform the start up. It would be less expensive than having someone less knowledgeable look at them first and not know how to get them running.

If the drives need to be re flashed, the ABB rep would be able to do this on the first shot.

GT

[valdelocc]

If the incoming power to the drive is present and the display stays blank chances are the fuses inside the drive are bad.

[ddcbacnet]

Nope, that's not fuses.
But I actually like the re flashing idea...
We have our own ABB certified start-up guy, but he was like wtf?. And he doesn't have a FlashDrop tool.
Will have to call their office on Monday.

I'll let you know what happens.

Thanks!

[GT Jets]

There should be 24VDC at the terminal strip, if that is not present there is a chance the drive is FUBAR..

Definitely let us know what transpires.

GT

[hands]

Were the VFD's properly shut down before the work was done in the building?

[B_roche]

In some cases if the drive lacks an external signal at f I think, it can act dead. Comes to life with the enabled command

Sent from my MZ601 using Tapatalk

[ryan1088]

In some cases if the drive lacks an external signal at f I think, it can act dead. Comes to life with the enabled command

Sent from my MZ601 using Tapatalk

I have noticed this also. Freezestat or an emergency shutdown makes everything go out....

[ddcbacnet]

I believe theres no such thing as proper shut down any more. at least not for AHUs. All speed drives now a day come with protection from over- and under-voltages, sudden power loss and shorts and opens on load side.
Safety interlocks (such as freezestat or FA) are usually normally closed dry contacts that are wired in series with digital inputs and cannot cause power loss of the entire drive.

We install a few dozens of those things every year, and I can tell you that this case is something much deeper or completely stupid and embarrassing.

[ryan1088]

I believe theres no such thing as proper shut down any more. at least not for AHUs. All speed drives now a day come with protection from over- and under-voltages, sudden power loss and shorts and opens on load side.
Safety interlocks (such as freezestat or FA) are usually normally closed dry contacts that are wired in series with digital inputs and cannot cause power loss of the entire drive.

We install a few dozens of those things every year, and I can tell you that this case is something much deeper or completely stupid and embarrassing.

I won't disagree with you on this. 99% of the time it is wired as you say and says "start enable missing" but you just never know.

[sdt1104]

I have seen this qiute bit in our system. When power is applied the display remains dark. In the power cabinet the pirmary contactor coil is bad. when you cycle power on this contactor closes to energize the VFD, you said you did not hear anything when power was applied.

[sdt1104]

An after thought - life safety alarms will have the same affect. Check you smoke and fire safties.

[HarryTheDog]

I would verify correct power to the drive first. If you still dont see anything on the panel I would try changing panels. If you still have no action I would properly lock out power and wait 5 minutes for capcitors to discharge and then check the fuses inside the outside panel. If fuses are good I would call ABB and let them have you check some other things with your meter. BTW someone said previously that your panel would be blank if there is no control signal and thats not true. If there's no signal the panel will still light up but the drive will be in alarm and not work. Hope this helps. gl and be careful!