Sub-mounted braking resistor protection
If an inverter contains a KEB sub-mounted braking resistor, data (e.g. resistance
value and temperature limits) are stored for the resistor in de86 build in brake re-
sistor.
A non-zero value in de86[2] means that a braking resistor download is present and
activated. In this case, parameter is31[1] braking resistor value contains the value
of de86[1] total resistor value and cannot be changed manually.
Additionally, is30 braking transistor function is automatically activated and cannot
be switched off.
When using a KEB sub-mounted braking resistor, the temperature of the braking
resistor wire is monitored by a calculation via a thermal resistance model.
➢ The thermal modeling is only sufficiently accurate if all installation settings re-
garding liquid cooling are observed (see installation manuals of the power
units).
Programmable reaction of the inverter when the warning
level is exceeded
Warning level overtemperature braking resistor
Adjustable from 400°C to maximum temperature of the
resistor (de86[5] max. temperature error level)
Error level overtemperature braking resistor
Adjustable from 400°C to maximum temperature of the
resistor (de86[5] max. temperature error level)
The braking resistor is protected by switching off the braking transistor when the
braking resistor temperature reaches the error threshold (pn91).
The error/warning thresholds are configurable by parameters pn90 brOH warning
level and pn91 brOH error level. The upper limit of pn90 and pn91 is set by sub-
mounted braking resistor data, found in the de parameters. de86[5] max. tempera-
ture error level shows the upper limit for pn90 / pn91.
The reset hysteresis is 80.0°C for the two thresholds.
If the brOH error level is exceeded, an error is triggered which switches off the
modulation and the braking resistor.
The reaction to exceeding the brOH warning level can be set in pn89 warning
brOH stop mode.
The error/warning response is displayed in parameters ru01 / st01, ru02, ru03.
Additionally, it can be parameterized in pn33 braking transistor options that the
braking transistor is deactivated when the warning threshold is exceeded.
If "warning" is set in pn89, it is possible to achieve that the braking transistor is al-
ready deactivated without switching off the modulation.
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