Theory of Hydraulic Magnetic Circuit Breakers

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Theory of Hydraulic Magnetic Circuit Breakers

Rather than employing separate heat and magnetic mechanisms for each purpose, the hydraulic magnetic circuit breaker is a unique sort of electrical protection device that combines overload protection and fault protection into a single mechanism. In situations where external factors like excessive temperatures or moisture may cause thermal protection to malfunction, hydraulic circuit breakers are useful. 

While thermal protection may inadvertently trip at high temperatures, it may not trip in low ones. This calls for the use of an alternate kind, such as high voltage dc contactor manufacturers in China. Hydraulic magnetic breakers are available for a broad variety of operating voltages up to 240 volts and frequencies of both 50 Hz and 60 Hz, much like all other circuit breaker types. 

They come in variants with one, two, or three poles, depending on the kind of circuit that needs protection. Hydraulic-magnetic circuit breakers are similar to small circuit breakers in that their current ratings are usually less than 100 amperes.

Principle of Operation of Hydraulic Magnetic Circuit Breaker 

The name “hydraulic magnetic circuit breaker” comes from the combination of a solenoid coil and a spring-loaded actuator inside a cylinder. It is filled with damping fluid to offer both overload and fault protection using a single mechanism.

Because of the solenoid coil, the greater-than-usual current creates a magnetic field for overload prevention. But because the overload current is just marginally more than the rated current, the actuator is dampened by the fluid and the magnetic field is not as strong, which gives the necessary time delay. 

The generated magnetic field grows in proportion to the overload current. So, this resulting in a shorter time delay as the magnetic force overcomes the damping effect faster. 

The same operating concept applies to fault prevention; however, the extremely high current creates a very strong magnetic field. Which rapidly overcomes the damping effect and results in an abrupt circuit disruption.

What separates a thermal magnetic circuit breaker from a hydraulic magnetic circuit breaker

The following are the primary distinctions between the two kinds of circuit breaker technology to take into account: 

Overload protection is achievable in thermal-magnetic circuit breaker types using a bimetallic strip that expands and contracts in response to temperature. Excessive heat is produced by overload currents, and the bimetallic contact widens until the circuit is broken. In contrast, a hydraulic-magnetic circuit breaker provides a time-delayed disconnection in the event of an overload. Thus, by utilizing a dampened spring actuator in conjunction with a solenoid coil, as previously mentioned. 

Both types of circuit breakers use the same fault prevention mechanism. Strong magnetic fields form in the solenoid coil and extremely high currents. They produce during a failure, such as a short circuit or line-to-ground fault. 

The circuit breaks down when the contact opens as a result of its magnetic field. In this case, the induced magnetic field and current are quite high. Therefore, there is no time delay due to the leading hydraulic magnetic circuit breaker.

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