What is the difference between a miniature circuit breaker and a molded case circuit breaker

The switch in the low-voltage distribution system is divided into three types: 1, frame circuit breaker (current is generally 400 6400) molded case circuit breaker (current general micro circuit breaker (current is generally the difference between molded case and micro break in addition to the difference in current range, the most important thing is the application, frame circuit breaker: mainly used in the main incoming line, the outgoing side of the transformer, in the low-voltage distribution system as a main switch and branch main switch, micro circuit breaker: mainly used at the end, that is, the end of the low-voltage distribution system, The lower end of it is the electrical equipment to be carried.

The plastic shell is the role of connecting the upper and lower levels. Pure hand-played, the writing is not very clear, if you don't understand something, you can ask.

Molded case circuit breakers have current levels up to 2000A. The maximum current level of the miniature circuit breaker is within 125A.

Due to the gap between the two in terms of capacity, in specific work, the effective area of the molded case circuit breaker is also greater than that of the miniature circuit breaker, and the connected wire is also relatively thick, which can reach more than 35 square meters, while the miniature circuit breaker is only suitable for connecting wires below 10 square meters. Therefore, generally for indoor conditions, it is more suitable to choose a molded case circuit breaker for larger rooms.

Circuit breaker function: under normal circumstances, turn on and off the no-load and load currents in the high-voltage circuit. In the event of a failure of the electrical system, it can cooperate with the protection device and automatic device to quickly cut off the fault current and prevent the accident from expanding, so as to ensure the safe operation of the electrical system.

These two things are too different, do you still need to use definitions?

Civilian use can be used plastic shell, industrial can also use micro breaking,

<> "1. What are the differences between frame circuit breakers and molded case circuit breakers?

1. The appearance and installation size are different.

The frame circuit breaker is large in size and volume, and the molded case circuit breaker is relatively small in size and volume.

2. The protection function of the tripper is different.

The frame circuit breaker intelligent tripper has protection function, auxiliary function, communication function, overvoltage protection, voltage unbalance and Li-mode phase loss protection, voltage harmonic alarm, current harmonic alarm, etc. The molded case circuit breaker has long delay protection, short delay protection and instantaneous protection.

3. The scope of application is different.

Frame circuit breakers are rated at 400A-6300A and are used in the distribution network to protect lines and power supply equipment. The quota current of the molded case circuit breaker is 10-800A, which is used for overload and short circuit when the line and equipment are disturbed in the distribution line, and provides protection for the line and equipment.

Second, the selection principle of low-voltage circuit breaker.

1. Determine the type and protection form of circuit breaker according to the protection requirements of the line, and determine the selection of frame type, device type or current limiting type.

2. When choosing a low-voltage circuit breaker, it should be noted that the rated voltage of the circuit breaker should be equal to or greater than the rated voltage of the protected line.

3. The rated voltage of the undervoltage tripper of the circuit breaker should be equal to the rated voltage of the protected line.

4. The rated current of the circuit breaker and the rated current of the overcurrent tripper should be greater than or equal to the calculated current of the protected line.

5. The ultimate breaking capacity of the circuit breaker should be greater than the maximum effective value of the short-circuit current of the line.

6. The protection characteristics of the upper and lower circuit breakers of the distribution line should be coordinated and cooperated, and the lower protection characteristics should be located below the upper protection characteristics and do not intersect.

7. For the long-delay trip current of the low-voltage call circuit breaker, it should be less than the allowable continuous current of the wire.

1. Differences in meaning.

The plastic case circuit breaker can be used to turn on and off the load circuit, and can also be used to control the plastic case type motor that starts infrequently.

Ordinary circuit breaker refers to a switchgear that can close, carry and break the current under normal circuit conditions and can close, carry and break the current under abnormal circuit conditions within a specified time.

2. The difference in function.

Plastic enclosure circuit breakers are generally used for power distribution and can also be used to protect electric motors. Under normal circumstances, the circuit breaker can be used for infrequent conversion of the line and infrequent starting of the motor.

The function of the ordinary circuit breaker is to cut off and turn on the load circuit, as well as cut off the fault circuit, prevent the expansion of the accident, and ensure safe operation. The high-voltage circuit breaker should break the arc of 1500V and the current is 1500-2000A, which can be stretched to 2m and continue to burn without extinguishing.

3. Differences in use.

Plastic enclosure circuit breakers are used to distribute electrical energy in the distribution network and to protect lines and power supply equipment from overload, short circuit and undervoltage. Circuit breaker for protection motor, used in the power distribution network for starting and breaking of squirrel cage motors and as overload, short circuit and undervoltage protection of rat motors. Undervoltage protection also requires the addition of a shunt tripper.

The purpose of ordinary circuit breaker is to distribute electric energy, start asynchronous motors infrequently, protect power lines and motors, and automatically cut off circuits when they occur serious overload or short circuit and undervoltage and other faults, and its function is equivalent to the combination of fuse switches and over/underheat relays.

Molded case circuit breaker: can automatically cut off the current when the current exceeds the trip setting.

Molded case circuit breaker model meaning:

1. The letter code of the product is represented by the following letters: S - less oil circuit breaker; d—multi-oil circuit breaker; k—air circuit breaker; l—sulfur hexafluoride circuit breaker; z—vacuum circuit breaker; Q—gas production circuit breaker; c—magnetic blowing circuit breaker.

2. The location code of the device; n - indoor, w - outdoor.

3. Design series sequence number; In numbers ??Denote.

4. Rated voltage, kv

5. Other supplementary working characteristic signs, G-Improved, F-Split-Phase Operation.

6. Rated current, a

7. Rated breaking current, ka