Motor Protection; Thermal Motor Model - Siemens SIRIUS M200D Manual

3.6

Motor protection

3.6.1

Thermal motor model

Description
The approximate temperature of the motor is calculated using the measured motor currents
and device parameters "Rated operating current" and "Tripping class". This indicates
whether the motor is overloaded or functioning in the normal operating range.
Response to overload - thermal motor model
You use this device parameter to specify how the motor starter is to respond in an overload
situation:
● Trip without restart (AUTO RESET = off)
Following an overload situation, the trip command cannot be reset until the motor model
has fallen below the reset threshold and a reset command has been issued after this (trip
reset).
● Trip with restart (AUTO RESET = on)
Once the cause of the fault has been eliminated (e.g. cooling down following
"Temperature sensor overload"), the motor starter automatically acknowledges the fault
message (= auto reset).
Motor restarts automatically if AUTO RESET is on.
Can Cause Death, Serious Injury, or Property Damage
The motor starter restarts automatically after the recovery time if a start command is
present (auto reset).
Make sure that you take appropriate measures to exclude the risk of hazardous conditions.
● Warning
Note
If the value of the thermal motor model exceeds the limit of 178% for self-protection of the
motor starter, the motor starter itself generates a trip command regardless of the
parameter assignment for "Response to overload - thermal motor model".
M200D AS-Interface Standard
Manual, 08/2014, A5E02548958A/RS-AA/004
WARNING
Functions
3.6 Motor protection
39