Thermal Protection And Automatic De-Rating; Operation From Unearthed Supplies; Lifetime Of Inverters - Siemens MICROMASTER 411 Operating Instructions Manual

Issue 03/01
10.5

Thermal Protection and Automatic De-rating

The MICROMASTER 411/COMBIMASTER 411 has comprehensive hardware and
software thermal protection.
Hardware: Fitted to the heatsink is a PTC resistor that will cause the inverter to
Software:
10.6

Operation from Unearthed Supplies

The MICROMASTER 411 cannot be used on unearthed input supplies.
10.7

Lifetime of Inverters

When the inverters are used in conjunction with Siemens motors (1LA7 and 1LA9)
the liftetime of the inverter is >= 20,000 hours.
MICROMASTER 411 & COMBIMASTER 411
6SE6400-5CA00-0BP0
trip if the temperature reaches 95 C.
When the heatsink reaches a temperature of within 5ºC of the trip
level, the switching frequency and output frequency of the inverter will
both be reduced. This reduces the Inverter losses and current and
attempts to prevent an overtemperature trip.
It is possible to prevent this reduction and select an immediate trip if
desired. See parameters P0290, P0292 for further details.
Instead of this reduction an immediate switching off also can be
selected. More information sie parameters P0290 and P0292
The inverter is further protected by an Inverter I
determines how hot the Insulated Gate Bipolar Transistors (IGBTs)
are and will reduce the current limit (P0640) when this calculation
reaches 95%. (User defined in P0294). If the I
2
100% an Inverter I t trip will occur (F0005).
Overtemperature in the inverter is usually caused by a high ambient
temperature or blocked convection.
Operating Instructions
10 Engineering Information
2
t calculation that
2
t continues to rise to
137