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Troubleshooting inverter problems
In extreme cases, it may be necessary to increase the inverter error tolerance to prevent safety shut-
downs caused by positioning faults (set option 22.2 = 1). This must only be done if an inverter error
of ±55 will not cause unsafe combustion.
PROBLEM
POSSIBLE CAUSE
SOLUTION
Inverter does not start because it does
not receive a RUN signal.
Ensure that the inverter receives a
RUN signal from the burner controller
at the same time as the Nexus PPC
5000 fuel air ratio control system.
Inverter has a slow start.
Late RUN signal.
Nonlinear output from inverter or
inverter’s PID is enabled
Ensure that the inverter’s slow start
feature is disabled.
Ensure that the inverter receives a
RUN signal from the burner controller
at the same time as the Nexus PPC
5000 fuel air ratio control system.
Check that the inverters output is
selected to be linear, and that the
inverters own PID loop is disabled.
Current limit reached
Noise
Slow down the inverter by increasing
it’s acceleration / deceleration time
settings.
Check cable shields.
Current limit reached.
Nonlinear output from inverter or
inverter’s PID is enabled.
Slow down the inverter by increasing
it’s acceleration / deceleration time
settings.
Check that the inverters output is
selected to be linear, and that the
inverters own PID loop is disabled.
Fan failed to stop before restart.
Increase the inverter stop time by
increasing option parameter 22.4 on
the Nexus PPC 5000 fuel air ratio con-
trol system.
Control is unstable
Adjust option parameters 22.1 & 22.3
on the Nexus PPC 5000 fuel air ratio
control system to reduce accuracy &
slow down control response.
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