Replacing MX 341 AVR with MX 321 AVR

[redlinej]

hello everyone,
The problem I am having is that I replaced a Stanford MX341 AVR with a MX321 AVR. The 341 is a good working avr, but the genset is going to be synchronize with two other gensets with 321.This is why we replace the 341 with the 321.The problem I am having with the new avr is that the voltage is not coming up to nominal voltage, its around 365 v (480 nominal).
This is what I think is wrong but cannot see how it can affect the regulation, so hope you guys can help.
The 341 is a two phase sensing avr and the 321 is a 3 phase sensing avr, and the manual say to use a open delta isolation transformer and I did not, instead I place the sensing at the mid point of the series wye connection.the nominal voltage for the genset is 480 V 60 hz and the avr is power from a PMG(120 hz).

 

[waross]

Which part of

WARNING!
Any devices connected to this input must be
fully floating and galvanically isolated from ground, with
an insulation capability of 500V ac. Failure to observe
this could result in equipment damage

did you not understand.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[redlinej]

That statement is referring to the analogue input A1 AND A2. The input that I am speaking about is the sensing input.

 

[IBRCAN]

Connecting the sensing as you describe should not pose any problem. Some regulators require a specific phase rotation for sensing. You may want to try switching two wires.

Is the under frquency roll off adjusted correctly?

Have you checked obvious things such as correct engine speed, rectifier diodes ok, PMG voltage correct?

 

[genhead]

Try disconnecting A1 & A2 to ensure that your sync controller is not driving the voltage down. Maybe A1 $ A2 are reversed?

 

[JSPRINGS]

Each Phase are different by 120 degree. If you choose the third phase to be between any other two,nthe phase difference remains only 60 degree difference, hence reducing the RMS voltage. So you should use the delta connection to generate the third phase.

 

[redlinej]

Good morning guys,

I finally got an open delta isolation transformer and connected it to the AVR,every thing work as it should, voltage came up and it synchronize with the other two generator.Thank you guys for your inputs.