Checking MPR-25s 2

[daleblizz]

The power in our building burped last night. The DC powered Option 81C got confused and all call processing stopped until it was initialized.

I'm trying to figure out why. We have four MPR-25s and I'm having trouble finding out how to troubleshoot them.

All are on FLT. From left to right on the top row the readings are: 3.9, 10.1 & 00.0

On the next row down, left side, the reading is 12.9.

Shouldn't these be reading close to same amount? What should I be looking at?

Any suggestions would be appreciated.

Thank you.

 

[daleblizz]

I probably should have mentioned that the MFA 150 is running at -54.9 volts and 23 Amps.

 

[DocVic]

When was the last time you tested the MFA? You might have a fat cell going bad. Time to schedule a power outage test and see how long you have on the batteries. Is the "float" level at zero? Time to do some testing.

DocVic
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[Reusser]

Different readings just indicate that the different rectifiers are carring different loads. From this info to, you could actually loose 2 rectifiers and still be able to handle load from PBX.

You should have your vendor come in an adjust the float so all rectifiers carry the same or lose to same load. This can be tricky as adjustments up on one also require a adjustment down on another in order to maintain same total current. To much or too low could cause switch to go down and will definatly shorten battery life.

Also because you said you lost power, you should have batteries tested by a battery company. One bad cell in the lot and you maight as well not have them.

 

[daleblizz]

Thanks DocVic and Reusser.

I have our vendor coming out. In 21 years I've probably installed DC power three times, so I'm going to let somebody who knows more about it look at it.

My guess is bad batteries. They were installed in 2004.

Thanks again.