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

[Dallas Duster]

If you remove the panel there is a red and green led I believe , see what they are doing. Then check that 24 VDC power supply.

[ddcbacnet]

yes, there is. they are both off

[targetman]

You may have a bad drive.

[TucsonTony]

I'm assuming it's a 480 or 208 primary. If that is present at the drives disconnect, are you making sure it is also getting out to the load side of the disconnect to the drive itself. Sometimes those disconects don't line up well with the handle on the outside of the drive. Those baby's have always lit up if they got power.

[ddcbacnet]

Ok, so...
Service tech from ABB came over today and declared 3 drives FUBAR on electronic level.

He took one of the drives with him to run it through some tests and determine the cause.

Now the cause is obviously somehow related to ongoing construction, but since those drives were wired by previous contractor, my boss ordered to withdraw the drive from the lab, reinstall it in place and let base building deal with it. (Kinda not our wires - not our problem).

Luckily for me, I have checked the drives before rewiring them. Otherwise would have been my fault.

:

Hopefully I will be able to find out what exactly have caused it. Things get pretty interesting...

[targetman]

I doubt you will be able to ever determine the cause of failure. I had the same issue with an ACH550 last summer. Power in and no power out. No LED lights.

[NoahsArcFlash]

I know that this particular case has been resolved, but I've also seen a faulty under-voltage relay keep the drive off

[ddcbacnet]

Faulty under-voltage relay? Is it possible to readjust at what voltage it drops out?

[ddcbacnet]

Well actually I didn't see it inside the drive. And voltage seems to be within the range (567-570V on 575V system)

[NoahsArcFlash]

Faulty under-voltage relay? Is it possible to readjust at what voltage it drops out?

In my case, the set-point (not even sure if it was adjustable, might have been) wasn't an issue. if i remember correctly, the relay was a NO contact in the control circuit portion of the drive. The coil went bad and it kept the drive off. I switched the connection to the NC terminal and presto it came to life (temp. fix of course)

[Mike Doran]

do you have o/m manuals? has pretty good troubleshooting chart at back of book or can call abb 800-help-365

[ddcbacnet]

Spoke to building engineer today. Speed drives are dead as a doornail and not subject to repair. It was caused by internal electronic failure within one of the components. Same component in all three drives. They did not mention which one.

They say they will never turn them off ever again

Lesson to learn: ALWAYS commission devices and systems you are about to upgrade.

[Jbart]

I have seen where someone accidentally hits a low voltage wire on a high voltage something (24volt wire hits a 277 volt leg) and instantly everything on that 24 volt circuit (safety or control) will never work again. Sometimes it is visible with small black arcing sports and sometimes not.