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Problem with SR489 Multilin

Problem with SR489 Multilin

Problem with SR489 Multilin

(OP)
Hi everybody, I'm getting a problem with one SR489 Multilin, one of its analog output sudently change signal level, This refers to MVAR, and is calibrated to:
 4mA=-3.37MVAR to 20mA=3.37MVAR.  At normal power factor it got 0.9MVAR but sudently it increased to maximum setting (3.37MVAR).  I did changed the input analog module on PLC in order to eliminate this posibility.  I see the problem is with SR489 relay.  What can I do, in order to fix it?  Thanks for your help.
Ealberto

RE: Problem with SR489 Multilin

If you set 4mA AND 20 mA equal to 3.37 MVAR, that's pretty much what you're going to be reading.  I assume the 4mA should be set to either 0 or -3.37 MVAR.  If the MW and MVAR are reading correctly on the meter, problems with the analog output must be related to the scaling factors, a wiring problem or a hardware problem in the 489.  I'd suggest putting a 1 ohm or similar precision resistor in series with the 4-20mA and checking the voltage.  This will enable you to determine the current output from the 4-20mA.  

Don't forget that the MVAR can be positive or negative.

RE: Problem with SR489 Multilin

Hi dpc,

 4mA=-3.37MVAR

There's a '-' symbol there. I didn't spot it either at first read. Agree with the rest. I'll enquire whether we've had anything similar with our Multilins.

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RE: Problem with SR489 Multilin

Sorry, I missed the minus sign.  My bad.

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