Limited touch protection
Degree of protection in conformity with IEC 60529:
IP 20 for devices 70 mm
IP 00 for devices > 70 mm
Shock-proof in conformity with DIN VDE 0106, Part
Installation and maintenance by technical personnel
only. Follow the operating instruction!
DISCONNECT POWER BEFORE PROCEEDING
WITH ANY WORK ON THIS EQUIPMENT.
The 3RB12 electronic overload relay protects electrical
equipment, such as three-phase AC motors and trans-
formers, with three different protection mechanisms.
The 3RB12 compares the motor current actually
flowing with the set current and evaluates the values
in a microprocessor.
PTC thermistors in the motor windings sense the motor
temperature. If the thermistor responds, the relay trips.
Versions with internal earth-fault detection are suitable
for service in three-wire systems.
Versions with earth-fault detection by means of an
external summation current transformer are suitable
for service in three-wire and four-wire systems.
CAN CAUSE ELECTRICAL SHOCK