Publication 2364F-5.05 - March 1999
2-4
Troubleshooting The RGU
Unit Overvoltage/Overcurrent
Trips
Check the following items if the unit frequently has an overvoltage or
overcurrent trip.
Does the Frame Catalog Number (P4) show
the appropriate catalog number for the unit?
Set P4 to match the catalog number shown
on the data nameplate (see Chapter 1).
Does the AC Line Inductance (P12) show
the total line inductance provided to the
RGU (including external components)?
Calculate the total inductance and set P12.
Does the External Capacitance (P203) show
the total capacitance for all inverters
connected on the DC bus?
Calculate the total capacitance on the DC
bus and set P203 appropriately.
Is the RGU being overloaded for extended
periods of time (beyond its rated capability)?
Adjust the period of overload application for
the RGU.
Are the burden resistors (on the isolation board)
at their rated resistance?
Test the main control board, gate driver board,
and isolation board (as instructed in Chapter 4).
Replace as necessary.
No
Yes
No
Yes
No
Yes
Yes
No
Yes
Push the disconnect lever to off and verify zero volts
across the DC bus before testing the following items.
!
ATTENTION:
Are drives on the DC bus set to allow a very
fast deceleration time (faster than the
voltage loop bandwidth of the RGU)?
Adjust the drives to an acceptable
deceleration time.
No
Yes
No
Is the current loop bandwidth (P198) high
enough for the application
Adjust P198 (Current Loop Bandwidth)
appropriately for the application (see the
setup chapter in publication 2364F-5.01).
No
Yes
Is the voltage loop bandwidth (P205) set
appropriately for the application?
Adjust P205 (Voltage Loop Bandwidth)
appropriately for the application (see the
setup chapter in publication 2364F-5.01).
Yes
Replace the damaged burden resistors.
No