Remote tripping
Shunt Trip (SHT) or Under Voltage Release (UVR/UVRN).
Shunt Trip (SHT)
“·This release trips the circuit breaker when the control voltage rises above 0.7 x
Un”
·Control signals can be of the impulse type (u 20 ms) or maintained.
Under Voltage Release (UVR/UVRN)
“·This release trips the circuit breaker when the control voltage drops below a
tripping threshold”
·Tripping threshold between 0.35 and 0.7 times the rated voltage
“·Circuit breaker closing is possible only if the voltage exceeds 0.85 times the
rated voltage.”
Operation
“When the circuit breaker has been tripped by an SHT or UVR/UVRN release, it
must be reset locally:”
·SHT or UVR/UVRN tripping takes priority over manual closing
“·in the presence of a standing trip order, closing of the contacts, even temporary,
is not possible.”
“Circuit breaker tripping by an SHT/UVR/UVRN release meets the requirements of
standard IEC 60947-2.”
