Siemens MICROMASTER 420 - Manual (Page 140)

3 Functions Issue 07/04
MICROMASTER 420 Operating Instructions
140 6SE6400-5AA00-0BP0
3.20.2 Thermal monitoring functions and overload responses
Parameter range: P0290 – P0294
r0036 – r0037
Warnings A0504, A0505
Faults F0004, F0005, F0012, F0020, F0022
Function chart number: -
Similar to motor protection, the main function of the thermal power module
monitoring is to detect critical states. Parameterizable responses are provided to
the user which allows the drive system to be still operated at the power limit thus
avoiding immediate shutdown. However, the possibilities of assigning parameters
only involves interventions below the shutdown threshold which cannot be changed
by users.
MICROMASTER 420 has the following thermal monitoring functions:
Heatsink temperature
The monitoring of the heatsink temperature r0037[0] of the power
semiconductor (IGBT).
i 2 t monitoring
The i 2 t monitoring is used to protect components which have a long thermal
time constant in comparison to the semiconductors. An overload with reference
to i
2 t is present if the drive inverter utilization r0036 indicates a value greater
than 100 % (utilization as a % referred to rated operation).
Normalized output current
t
100 %
Reaction via P0290
Default: "current reduction"
r0207
r0027
P0294 (95 %)
t
i 2 t [%]
r0036
1
0
A0505
t
Fig. 3-59 Drive inverter response to an overload condition
Parameter P0290 defines how the drive inverter responds to an overload condition.
The following settings are possible:
0 "Reduce the output frequency"
1 "Shutdown (F0004)"
2 "Reduce the pulse frequency and output frequency"
3 "Reduce the pulse frequency then shutdown (F0004)"