Magnetic Circuit Breaker Has Trip Action

When a short circuit occurs the current flowing through the circuit conductor causes the magnetic field strength of the electromagnet to increase rapidly and attract the armature as shown in fig.

Magnetic circuit breaker has trip action.

Thermal magnetic tripping units the thermomagnetic trip unit consists of two parts. A delayed b instantaneous c both of the above d none of the above. Overloaded circuits loose or faulty wiring and lightning can cause the circuit breaker to trip. A magnetic circuit breaker is a safety device designed to cut an electrical current in the event of a power surge thus protecting electrical equipment and circuitry from damage.

So in case of a magnetic circuit breaker a solenoid or an electromagnet is attached to the trip unit. Magnetic circuit breaker has trip action. Phase to phase single phase to ground double phase to ground three phase short circuit in a contactor interrupting medium may be air oil sf 6 gas any of the above. The thermal trip unit made up by a bimetal thermal device which actuates the opening of a circuit breaker with a delay depending on the overcurrent value.

The trip unit is the part of the circuit breaker that determines when the contacts will open automatically. Asked in switchgear and protection by questionanswer. Charging action of capacitor. Short circuit trip action uses an electromagnet having a winding that s in series with the load current.

The magnetic trip unit made up by an electromagnetic device with fixed fixed. The magnetic field moves a switch tripping the breaker and clearing the fault. This trip unit is intended for the protection against overloads. The circuit breaker will trip as shown in figure 2 21 view b.

In a thermal magnetic circuit breaker the trip unit includes elements designed to sense the heat resulting from an overload condition and the high current resulting from a short circuit. Thermal circuit breaker has delayed trip action instantaneous trip action both of the above none of the above gives rise to symmetrical fault. Magnetic circuit breaker has trip action. The function of the solenoid or the trip unit is to generate a magnetic field.

This circuit breaker has tripped even though the thermal element has not had time to react to. If the current suddenly or rapidly increases enough the magnetic element will attract the trip bar release the latch and the circuit breaker will trip as shown in figure 2 21 view c. This is done when the current passes through the solenoid magnetism develops in it due to changing magnetic flux and a magnetic field is created around the solenoid. There are other devices able to break a circuit during a surge or short circuit each with its own limitations.

A magnetic circuit has effective iron length of 100 cm and it is wound with 800 turns of wire carries 1 a.