DZ20 Molded Case Circuit Breaker (125A/150A/200A/350A/500A Circuit Breaker, hereinafter referred to as MCCB), its rated insulation voltage is 660V, AC 50Hz, rated voltage is 380V and below, and its rated current is 16A to 1250A. Generally for power distribution, Y, J-type circuit breaker of rated current of 225A and below and the frame of 400Y-type can also protect motor. Under normal circumstances, DZ20 MCCB can apply to infrequent conversion of circuits and infrequent starting of the motor.
DZ20 MCCB (125A/150A/200A/350A/500A Circuit Breaker) for distribution, distributes power in the distribution network, and can protect overload and short-circuit of circuits and power equipment.
DZ20 Lv Circuit Breaker (125A/150A/200A/350A/500A Circuit Breaker) for motor protection in the distribution network can apply to starting and breaking in the running of squirrel-cage motor and overload, short-circuit protection of motor.
The series, the three-pole DZ20 MCCB of frame rated current of 100A to 630A also have transparent cover, the cover is made of polycarbonate material with new type, high temperature resistant and high strength. DZ20 MCCB can be judged on or off of the contact state directly, widely used in the construction site temporary electricity field.
Meet the standards: GB14048.2, IEC60947-2.

Model Meaning Note:
A. Commonly used products without code; transparent cover products with "T";
B. Distribution circuit breaker without code; circuit breaker for motor protection with "2";
C. Handle direct operation without code; electric operation with P; the turning handle with Z (products of frame grade of 1250A without turning handle);
D. According to the rated ultimate short-circuit breaking capacity: Y-general type, J-higher type.

Note:
A. The specifications listed in Table 1 shall be selected by the user as required, but shall not exceed the items specified in each box in Table 1 in a circuit breaker
B. Circuit breaker of frame grade of 100A, 225A, each set of auxiliary contacts are set as one normally open, one normally closed, each set of the rest of circuit breaker is composed of contacts set as two normally open, two normally closed;
C. Alarm contacts are set as one normally open, one normally closed; DZ20C-160 has no alarm contacts and electric rotation operating specifications, DZ20-1250 has no alarm contacts;
D. There are no specifications of 248, 278, 348, 378 in the frame grade of 100A, 225A;
E. Thermal magnetic release, is the release with magnetic release and thermal release;
F. There are no specifications of 230, 330, 238, 338, 250, 350, 270, 370 in DZ20J-1250.

Current setting value of circuit breaker short-circuit protection

Note: DZ20Y.J-100 circuit breaker, when In ≤ 40A, the instantaneous operating current value is 600A, non-operating current is 10In.

Protection characteristics of circuit breaker

Inverse time off characteristics of circuit breaker for distribution

Inverse time off characteristic of circuit breakers for motor protection

Shunt release:
Rated control power supply voltage: AC220V, AC380V.
Shunt releases shall be reliable to make the circuit-breaker trip at the rated control supply voltage of 70% to 110%.
Undervoltage release:
Rated operaing voltage: AC220V, AC380V.
When the voltage drops (or even slow down) to 70%~35% of the rated voltage range, undervoltage release should act, at less than 35% of the rated voltage release, undervoltage release should be able to prevent open circuit When the supply voltage is equal to or greater than 85%, the circuit-breaker shall be closed.
Alarm contact:
Rated operating voltage: AC220V.
Conventional heating current: 1A.
Auxiliary contacts: Install the undervoltage release and shunt release at different time, you can install the auxiliary contact. Rating value of auxiliary contact (see Table 6); making and breaking capacity (see Table 7); auxiliary contact has the same times of non-operating performance as circuit breaker, times of power-on operation is 6050 times, when the times of operating performance of circuit breaker is less than 6050 times, then the same as circuit breaker.

External accessories of the circuit-breaker

● The relevant parameters of electric operating mechanism and the total height H of circuit breaker with electric operating mechanism in Table 8.

● Installation dimensions of manual operating mechanism are shown in Table 9

This series circuit breakers is based on Y-based products, consists of the insulation case, operating mechanism, the contact system and the release. The operating mechanism of the circuit breaker has the function of quickly closing and breaking the contacts, and the positions of "CLOSING", "OPENING" and "FREE RELEASE" are distinguished by the handle position.
J-type circuit breakers are derived from the Y-type basic products. J-type circuit breaker improve the structure of the Y-type circuit breaker contact, so that in the case of short circuit, before the mechanism action, the moving contact can be quickly disconnected to achieve the purpose of improving the making and breaking capacity.

Keywords: DZ20 , 350A Circuit Breaker