Siemens SIRIUS 3RH Series - Functions; Overload and Short-Circuit Protection

SIRIUS 3RV2 motor starter protectors
4.4 Functions
SIRIUS Innovations
386 System Manual, 01/2011, A8E56203870002-03
4.4 Functions
3RV2 motor starter protectors meet the requirements for motor and system protection
according to IEC 60947-2 / DIN VDE 0660-101.
Motor and system protection is achieved using the following functions:
● Overload protection
● Short-circuit protection
● Phase loss sensitivity
4.4.1 Overload and short-circuit protection
Overload protection
The current of the motor requiring protection is set on the setting scale. This sets the
integrated overload protection to the motor current.
Short-circuit protection
The short-circuit release is factory-set to a value that is 13 times the rated current of the
motor starter protector (upper setting scale). This ensures problem-free ramping-up and safe
protection for the motor.
Release
3RV2 motor starter protectors are fitted with the following releases:
● Inverse-time delayed thermal overload release (except for the 3RV23)
● Instantaneous short-circuit release
The overload releases can be set to the load feeder.
Note
Motor starter protectors for transformer protection
The motor starter protectors and circuit breakers for transformer protection (3RV24, 3RV28)
are set to 20 times the rated current to prevent undesirable tripping due to the high inrush
current.