The difference between a Shunt Trip and a Trip Coil
The difference between a Shunt Trip and a Trip Coil
(OP)
In Circuit Breaker applications, what is the difference between a Shunt Trip and a Trip Coil?
For instance in one 600V PDC drawing, I see that the relay which trips the 2000A secondary CB is labeled as "ST."
However, for the 4kV PDC drawing, I see that the relay coil that trips the 2000A secondary CB is labeled as "TC."
The intended purpose of both types is to trip the CB (that's easy! j/k)... But I'm curious, what is the difference between the two types?
Regards,
Maj
For instance in one 600V PDC drawing, I see that the relay which trips the 2000A secondary CB is labeled as "ST."
However, for the 4kV PDC drawing, I see that the relay coil that trips the 2000A secondary CB is labeled as "TC."
The intended purpose of both types is to trip the CB (that's easy! j/k)... But I'm curious, what is the difference between the two types?
Regards,
Maj






RE: The difference between a Shunt Trip and a Trip Coil
RE: The difference between a Shunt Trip and a Trip Coil
- shunt trip coils : were the application of voltage causes the coil to trip the breaker
- an undervoltage trip coil : where removing the voltage causes the coil to trip the circuit breaker (or application of voltage of voltage is required to close and maintain the breaker closed)
RE: The difference between a Shunt Trip and a Trip Coil
Bill
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"Why not the best?"
Jimmy Carter
RE: The difference between a Shunt Trip and a Trip Coil
Like Aleham said, "shunt trip" is the term used in low voltage, e.g. molded case, circuit breakers where it is commonly an add-on component. The CB has thermal/magnetic trip capabilities, but it also has the ability to trip electronically say from a Feeder Protection Relay say like the GE SR750.
"Trip Coil" was used in reference to Power CB (in this case Medium CB.) The CB has no thermal/magnetic trip capabilities, it requires "brains" to tell it when to trip electronically from a monitoring relay such as the GE SR750 :)
Cheers,
Maj