Moulded Case Circuit Breaker MCCBs are only available in two types: electromagnetic and electronic. The electromagnetic type means that the overload maintenance module consists of a thermomagnetic element, i.e. bimetal + magnetic coil, while the electronic type means that the overload maintenance module consists of a CT/PT + electronic element.

Both maintenance modules can perform long-delay, short-delay and instantaneous maintenance, but the calculation of the action current and timing accuracy is different. Prices are, of course, far apart, with the budget option of the electronic type and, conversely, the electromagnetic type.

Difference between molded case circuit breaker and electronic molded case circuit breaker

Plastic case circuit breaker is the operating system organization, etc. are installed in the design of a Chinese plastic shell, generally do not consider for repair, suitable for use as a branch maintenance work switch, overcurrent decoupler has thermal magnetic and electronic two kinds, general thermal magnetic plastic case circuit breaker for non-selective circuit breaker, only information overload long delay and short circuit instantaneous generation of two ways maintenance management approach, electronic type plastic case circuit breaker has overload long delay , short-circuit short delay, short-circuit transient and grounding technology defect analysis four kinds of relationship maintenance social function. A part of the electronic type molded case circuit breaker new product development also comes with area can be selective as well as chain function. Most of the plastic case circuit breaker for manual mode operation, there are also important part of the enterprise with motor has operator organization.

Plastic case heating electromagnetic type circuit breakers, most of the early circuit breakers using this structure, using the electro-thermal effect and electromagnetic effect, the thermal effect is achieved by the bimetallic structure, when the bimetallic bending deformation to a certain extent, press the switch tripping device, the switch trips, the switch thermal overload current is adjusted by mechanical adjustment screws, the adjustment accuracy is not high, this is due to the role of the inverse time limit, that is, the greater the current, the action time The shorter the action time, some large switches such as circuit breakers.

The thermal overload current does not directly use the bimetal plate structure, but uses the current transformer, which converts the primary current into a secondary current, which is connected to the thermal relay, and then the switch is turned on through the normal opening or normal closing of the contacts of the thermal relay, the operation of the tripping coil, and the instantaneous high current tripping is due to the use of the magnetic effect, with a structure similar to an electromagnetic coil at the lower end of the switch, when there is a high current or short circuit current (overload The current is much larger than the switch's 0, constituting an inhalation solenoid coil that directly drives the switch tripping device and regulates the switch's instantaneous tripping current by means of a mechanical adjustment screw.

The electromagnetic structure does not require an external power supply and is highly resistant to interference. The tripping coil cannot be used.

Electronic, that is, we go through a current transformer circuit, check the control switch working current, the current value to manipulate the system output, the output to manipulate the trip coil, so that the switch trips, the advantage is high precision, adjust their own convenience, directly through the set value or the use of potentiometer adjustment.

The disadvantage is the need to use trip coils, the need for power, electronic circuit problems more difficult to deal with, anti-interference ability is almost.