Function Diagram - Siemens SINAMICS G150 Operating Instructions Manual

Functions, Monitoring, and Protective Functions
9.4 Monitoring and protective functions
Thermal 3 mass model (for induction machines)
For induction machines, the motor temperature is calculated using the thermal 3-mass
model. This makes thermal motor protection possible – even for operation without
temperature sensor or with the temperature sensor deactivated (p0600 = 0).
For operation with a KTY sensor, the calculated temperature value of the 3-mass model
permanently tracks the measured temperature value. After the temperature sensor is
switched off (p0600 = 0), the last temperature value continues to be used for calculation.
Thermal I2t motor model (for permanently excited synchronous machines)
By using the thermal I2t motor model, the temperature rise of the motor windings as a result
of dynamic motor loads is also determined in addition to data acquired using a temperature
sensor.
If the thermal I2t motor model is activated via p0612.0 = 1, it calculates the motor load
(r0034) from the following values:
● Absolute value of the actual current, unsmoothed (r0068[0])
● Motor stall current (p0318)
● I2t motor model thermal time constant (p0611)
● Measured motor temperature (r0035) or motor ambient temperature (p0625) for operation
If the fault threshold is exceeded (set via p0605; delivery state after commissioning 155 °C),
alarm A0712 "I2t motor model overtemperature" is triggered.
When the I2t motor model fault threshold is reached (p0615), fault F07011 is triggered in
conjunction with the setting in p0610.
9.4.5.6

Function diagram

FP 8016
FP 8017
FP 9576
504
without temperature sensor
Thermal monitoring motor
Thermal I2t motor model (PEM, p0300 = 2xx)
TM31 - temperature evaluation (KTY/PTC)
Converter cabinet units
Operating Instructions, 03/2012, A5E03263466A