30 6SE6400-5BA00-0BP0
P0610 Motor I2t temperature reaction Min: 0
CStat: CT Datatype: U16 Unit: - Def: 2
P-Group: MOTOR Active: first confirm QuickComm. No Max: 2
Defines reaction when motor I2t reaches warning threshold.
Possible Settings:
0 No reaction, warning only
1 Warning and Imax reduction (results in reduced output frequency)
2 Warning and trip (F0011)
Dependency:
Trip level = P0614 (motor I2t overload warning level) * 110 %
Note:
The purpose of motor I²t is to calculate or measure the motor temperature and disable the inverter if the
motor is in danger of overheating.
The motor temperature will be dependent on many factors, including the size of the motor, the ambient
temperature, the previous history of the loading of the motor, and of course, the load current. (The square of
the current actually determines the heating of the motor and the temperature rises with time - hence I²t).
Because most motors are cooled by built in fans running at motor speed, the speed of the motor is also
important. Clearly a motor running at high current (maybe due to boost) and a low speed, will overheat more
quickly than one running at 50 or 60 Hz, full load. The MM4 take account of these factors.
The drives also include inverter I²t protection (i.e. overheating protection, see P0290) in order to protect the
units themselves. This operates independently of the motor I²t, and is not described here.
I²t operation:
The measured motor current (r0027) is compared with the rated motor current (P0305), and other motor
parameters (P0304, P0307, etc.), and the temperature of the motor calculated, a calculation which also
includes the output frequency (motor speed) to account for fan cooling. If parameter P0335 is changed to
indicate a forced cooled motor, the calculation is modified accordingly.
Where parameters are not entered by the user, such as P0344 (motor weight), a calculated value will be
used based on a Siemens motor. If required, the motor time constant can be adjusted using P0611, in effect
overwriting the calculated value.
The resulting temperature is displayed in % of maximum temperature in r0034. When this value reaches
the value set in P0614 (default 100%), a warning A0511 occurs. If no action is taken and the temperature
reaches 110%, then the inverter trips, showing F0011. The reaction to the warning can be changed from
this default using P0610; for example, the drive can react as though a current limit has occurred, or a fault
forced immediately. The warning level of P0614 can also be adjusted to raise and lower the warning or trip
level as required.
Parameter r0034 is particularly useful to monitor if the calculated motor temperature is rising excessively.
P0611 Motor I2t time constant Min: 0
CStat: CT Datatype: U16 Unit: s Def: 100
P-Group: MOTOR Active: Immediately QuickComm. No Max: 16000
Defines motor thermal time constant and is calculated automatically from the motor data (see P0340).
Notice:
A larger number increases the time taken for the calculated motor temperature to change.
Default value is dependant on inverter rated power.
P0614 Motor I2t overload warning level Min: 0.0
CStat: CUT Datatype: Float Unit: % Def: 100.0
P-Group: MOTOR Active: first confirm QuickComm. No Max: 400.0
Defines the [%] value at which alarm A0511 (motor overtemperature) is generated.
Motor I2t calculation is used to estimate a maximum tolerable period (i.e. without overheating) for motor
overload. The I2t calculation value is deemed = 100 % when this maximum tolerable period is reached (see
r0034).
Dependency:
A motor over-temperature trip (F0011) is produced at 110 % of this level.
P0640 Motor overload factor [%] Min: 10.0
CStat: CUT Datatype: Float Unit: % Def: 150.0
P-Group: MOTOR Active: Immediately QuickComm. Yes Max: 400.0
Defines motor overload current limit in [%] relative to P0305 (rated motor current).
Dependency:
Limited to maximum inverter current or to 400 % of rated motor current (P0305), whichever is the lower.
Details:
See function diagram for current limitation.
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cheers