DZ20 molded case circuit breaker type structure characteristics
Plastic casing type circuit breaker brand variety, a typical domestic models for DZ20 plastic casing circuit breaker. Generally speaking, the product of a lot of points, so this paper describes in detail the DZ20 circuit breaker of various models of meaning and the corresponding structural features.
DZ20 series moulded case circuit breaker type name and its meaning are as follows:
Among them: 1, plastic casing type circuit breaker 2, design code
3 - rated ultimate short-circuit breaking capacity level of general type: Y; J - G - the highest high type; type; C - economy
4 - rated current of frame ( A ) 5, mode of operation: handle operation directly without code; electric operating P representation; turning handle operation is indicated by Z
6 - pole number respectively 2, 3, 4 polar representation
7 - release mode and accessory code, see the company's production of DZ20 circuit breaker product page
8 - use code: distributor breaker without code; motor protection circuit breaker with 2.
For example, DZ20-250 / 330, DZ series moulded case circuit breaker, the rated current of 3 250A, pole, double release, without fittings.
Then introduced the competence level a different meaning. DZ20 series plastic shell circuit breaker has four kinds of property type, with Y as the basic type is called the general type. Type C (economy), type J ( higher type) and type G ( high breaking capacity for circuit breaker type ) is the type Y derived products, type C circuit breaker in addition to limit breaking capacity and different, basically the same in structure. In addition to derive a quadrupole and without arcing and other products. General type ( type Y ) circuit breaker when the circuit short circuit current, release action, contact was disconnected to cut off the short circuit current, type Y circuit breaker switching ability than J small. J type is the type Y circuit breaker structure was improved, when the short circuit current reaches a certain value, the contact occurs between the contact electric power, the moving contact repulsion to form larger repulsion distance, then the circuit breaker tripping device. Due to the use of contact electric repulsion and release release at the same time, shortens the opening time and improves the short-circuit breaking capacity, its full opening time in 14ms. Type G circuit breaker is in type Y circuit breaker base after connected in series with a parallel conductor composed of repulsion limiting contact system ( also known as the current-limiting device ), the contact system than type J repulsion contact length, disconnected distance is also large, so as to more rapid current-limiting. Under normal circumstances the open and closed by upper type Y circuit breaker to complete. When a short circuit, limiter contact immediate repulsion, arc appears, arc resistance limits the short current rising, because at the same time tripping mechanism of action, the moving contact is opened, contact distance increases, the arc resistance also increases further, in the 4-5M will short-circuit current limitation to the maximum actual breaking current, in 8-10m in breaking short-circuit current. Due to a current limiter dynamic, static contact parallel conductor length, the repulsion, the moving contact repulsion distance is large, and the repulsion is also fast, so limiting effect remarkable.
Then simply say DZ20 air switch ( molded case circuit breakers in general can also call the air switch ) structural characteristics. The circuit breaker comprises an insulated shell, operating mechanism, the arc extinguishing system, a contact system and a tripping device is composed of four parts. Operation mechanism of circuit breaker using the traditional four bar structure, having a spring energy storage, fast" and"," cent" function. Make contact with fast closing and breaking function, its" close"," branch"," discount" and" tripped" position to the position of the handle to differentiate. Arc extinguishing system is composed of arc-extinguishing chamber and the surrounding insulating sealing plate, insulation clamping plate. Insulation casing insulating base, the insulating cover, import and line end insulation sealing plate. The insulating base and the cover is the breaker improving breaking capacity, reduce the volume, increase the important components of rated capacity. Contact system of &7!, unified by the moving contact, a static contact. 630A and below the circuit breaker contacts, the single point. 1250A breaker moving contact is composed of a main contact and arc contact.
The above information is for reference only, national electrical switch factory, www.jiandq.com