Applications
3.1 Use of the 3VA UL molded case circuit breakers in line protection
3VA molded case circuit breakers with UL and IEC certification
102
Manual, 01/2019, L1V30435333-01
3.1.2
Versions of the trip units
3.1.2.1
Thermal-magnetic trip units
TMTUs for line protection applications
Derating
Thermal-magnetic trip units employ a temperature-dependent bimetal to provide overload
protection. The setting values are calibrated at an ambient temperature of +40 °C.
Compensation factors must be applied for ambient temperatures greater than +50 °C.
You will find more information and derating factors in chapter Derating (Page 454).
Thermal-magnetic trip unit TM210 LI
Line protection FTFM - function LI
The thermal-magnetic trip unit TM210 has:
●
Fixed parameter setting I
r
for overload protection (L)
●
Fixed parameter setting I
i
for instantaneous short-circuit protection (I)