Thermal Motor Model 1 - Siemens SINAMICS S120 Function Manual

Depending on the particular model, the temperature rise is either assigned different motor
parts (stator, rotor), or is calculated from the motor current and the thermal time constant. A
combination of motor temperature model with additional temperature sensors can also be
used.
NOTICE
Risk of the motor overheating through operation without a sensor
A thermal motor model cannot fully replace a sensor. The thermal model cannot protect the
motor if incorrectly installed, for increased ambient temperatures or if errors were made in
the parameter settings. Without temperature sensors, thermal motor models are not in a
position to identify or take into account the ambient temperatures or the initial motor
temperature.
9.5.1.1

Thermal motor model 1

Thermal motor model 1 is only used for synchronous motors. It is based on a continuous
current measurement. The dynamic load of the motor is determined from the motor current
and the motor model time constant. The actual value of the motor winding temperature can
be measured using a temperature sensor and subsequently taken into account.
The thermal I2t motor model is activated with p0612.00 = 1.
The motor utilization is displayed in parameter r0034. Parameter r0034 is calculated from the
following values:
● Absolute current actual value r0068
● I2t motor model thermal time constant p0611
● Motor stall current p0318
● Measured motor temperature r0035
When the alarm threshold p0605 is exceeded, alarm A07012 "Motor temperature model
overtemperature" is output.
If the fault threshold p0615 is exceeded, fault F07011 "Motor overtemperature" is output.
Drive functions
Function Manual, (FH1), 04/2014, 6SL3097-4AB00-0BP4
Monitoring and protective functions
9.5 Thermal motor protection
553