User's Manual

Protect PV.500_MH Operating Instructions
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Variable speed
depending on IGBT
temperature
Fan switched off
Initialisation
Maximum speed,
minimum time!
IGBT temperature
< limit value
IGBT temperature
> limit value
Minimum time elapsed
Figure 8 Fan control
5.2.5 Parameters of Inverter Stack Fan Control
IGBT temperature limit value for switching off the fan:
If the highest IGBT temperature falls below this limit value, the fan
is switched off.
IGBT temperature limits and fan speeds, x-y coordinates for
determining variable speed:
The variable fan speed is determined by a linear x-y characteristic
on the basis of these values.
IGBT temperature limit:
If the IGBT temperature rises above the lower limit value, the fan
that was previously switched off is run at maximum speed for the
minimum time.
Minimum time, maximum speed:
If the minimum time has elapsed, the fan is controlled variably us-
ing the measured IGBT temperature.
5.3 Insulation Monitoring and Earthing of PV Cells
5.3.1 General
Insulation measurements and tests are carried out with an inte-
grated isometer. This unit detects and checks the insulation re-
sistance.
The insulation resistance detected is compared with two limit val-
ues stored in the isometer. If the insulation resistance is below one
of the limit values, the unit generates a signal. If the limit value is
below the other limit value, the device generates a second signal.
The limit values can be displayed and even modified on the isome-
ter.