Products & Solutions

Place of Origin: China
Brand Name: Longsun
Model Number: LTZM1E
Minimum Order Quantity: 1 pc
Delivery Time: 15 working days
Payment Terms: L/C, T/T, Western Union, etc.



Electronic Molded Case Circuit Breaker(MCCB)


LTZM1E series electronic molded case circuit breaker (hereinafter referred to as circuit breaker) is suitable for low-voltage power grids with AC 50Hz, rated insulation voltage 800V, rated working voltage 400V and below, rated working current up to 800A. The circuit breaker has overload long-delay inverse time, short-circuit short-delay inverse time, short-circuit short-delay definite time, and short-circuit instantaneous and Undervoltage protection functions. Under normal circumstances, the circuit breaker is used for the infrequent switching of lines and the infrequent starting of motors. The circuit breaker can be equipped with accessories such as Undervoltage release, shunt release, auxiliary contact, alarm contact, electric operating mechanism, and rotating operating handle.


*There is no code for power distribution protection, and the motor protection code is represented by 2
*There is no code for manual direct operation, and D for electric operation.



Scope of application and standards


Scope of application

Electronic molded case circuit breakers (hereinafter referred to as circuit breakers) are suitable for low-voltage power grids with AC 50/60Hz, rated insulation voltage 800V, rated current 16A-800A, and rated working voltage 400V. Because the circuit breaker is equipped with an intelligent release device, it not only increases the selection range of the setting current but also has three-stage protection functions of overload long delay, short circuit short delay, and short circuit instant.

Purpose of parts

Electronic series circuit breakers can be equipped with circuit breaker accessories such as Undervoltage release, shunt release, auxiliary contacts, alarm contacts, electric operating mechanisms, and rotary operating handle mechanisms.
Its use is as follows
The undervoltage release is used for the undervoltage protection of lines and power supply equipment.
The shunt release is used to remotely control the disconnection of the circuit breaker.
Auxiliary contacts are used for automatic control of circuit breaker-related control circuits and signal circuits.
The alarm contact is used to alarm the overload, short circuit, and undervoltage accident tripping of the circuit breaker protection object
The electric operating mechanism is used for the automatic control and remote closing and opening of the circuit breaker.
The rotary operating handle mechanism is used to operate the circuit breaker outside the switch cabinet door and mechanically interlock with the cabinet door when the circuit breaker is in the closed state.


Electronic series circuit breakers comply with the following standards:
GB14048.1 “Low-voltage Switchgear and Controlgear Part 1: General Rules”
GB14048.2 “Low-voltage Switchgear and Controlgear Part 2: Circuit Breakers”
GB14048.4 “Low-voltage switchgear and control equipment electromechanical contactors and electric starters”
GB14048.5 “Low-voltage switchgear and control equipment Part 5-1: Control circuit appliances and switching elements electromechanical control circuit appliances”



Normal working conditions

Ambient air temperature: -5C-+40C, the average value within 24 hours does not exceed +35C.

Altitude The altitude of the installation site shall not exceed 2000m.

Atmospheric conditions The relative humidity of the atmosphere at the installation site does not exceed 50% when the ambient maximum temperature is +40°C; when the monthly average minimum temperature of the wettest month is +25°C, the monthly average maximum relative humidity of the month is 90%, and the temperature change should be considered Condensation that occurs on the surface of a product.

Installation category: 3

Pollution level: The pollution level of the installation site is level 3.

Installation conditions: The external magnetic field of the installation site should not exceed 5 times the geomagnetic field in any direction. Generally, intelligent circuit breakers should be installed vertically.

Wiring method: screw terminals are used, and the wires are compressed with screws.


Using category code:

In the case of a short circuit, the class A circuit breaker is not clearly specified as the selective protection of another short circuit device connected in series on the load side, that is, in the case of a short circuit, the selective protection has no artificial short delay. Corresponding circuit breaker: 125, 250

In the case of a short-circuit of Class B, the circuit breaker is clearly specified as a selective protection for another short-circuit device connected in series on the load side, that is, in the case of a short-circuit, the selective protection has a circuit breaker corresponding to an artificial short-time delay (adjustable): 400, 630, 800, 1250.


Note: The first digit 3 of the release mode and internal accessory code indicates an electronic release with three-stage protection. The last two digits indicate the internal accessory code, if there is no accessory, use 00 to indicate



According to the purpose of the circuit breaker: power distribution protection; motor protection
According to the number of poles of the circuit breaker: three poles; four poles
According to the operation mode of the circuit breaker: direct operation of the handle; electric operation; operation by turning the handle
According to the wiring method of the circuit breaker: front panel wiring; rear panel wiring; plug-in wiring


Performance and parameters

Circuit breaker rated current value

Frame rating rated current InmA Short circuit breaking capacity level Short-circuit breaking capacity kA* (effective value) Icu/lcs Circuit breaker rated current In(A)
125 L 35/22 32A (setting current range 16A-32A)
63A (setting current range 32A-63A)
125A (setting current range 63A-125A)
M 50/35
H 85/50
250 L 35/22 250A (setting current range 100A-250A)
M 50/35
H 85/50
400 L 65/42 400A (setting current range 200A-400A)
M 85/55
H 100/65
800 L 65/42 630A (setting current range 400A-630A)
800A (setting current range 630A-800A)
M 85/55
H 100/65
1250 M 85/50 1250A (setting current range 400A-1250A) 1250A (setting current range 800A-1250A)

*Power factor due to test current I, I≤10KA 0.5,10KA<I≤20KA 0.3,20KA<I≤50KA 0.25,I>50KA


Action characteristics of long-time overcurrent protection for circuit breaker controller

Current Action time
For power distribution 1.05 Irl Do not act within 2 hours
1.3lrl ≤Ih action
2Irl Settling time t1(S) In m=125, 250A In m=400A, 630A, 800A, 1250A
12 60 80 100 12 60 100 150
For motor protection 1.05Ir Do not act within 2 hours
1.2 Irl ≤Ih action
1.5Irl Action time T1(S) In m=125, 250 In m=400、630A
21.3 107 142 178 21.3 107 178 267
2lrl Settling time t1(S) 12 60 80 100 12 60 100 150
7.2Ir1 Action time T1(S) 0.93 4.63 6.17 7.72 0.93 4.63 7.72 11.6
/ 10 10 20 one 10 20 30

1. Action time complies with I2T 1=(2lr)2t; (1.2Ir 1≤I<lr 2)
2. Action time tolerance is ±20%;
3. Returnable time is not less than 70% of action time.


Action characteristics of short-time overcurrent protection of circuit breaker controller

Current Action time
rated current 125A 250A 400A 630A 800A 1250A
Ir2≤1<1.5Ir2 Inverse time limit I2T2=(1.5Ir2)2t2
1.5lr2≤1<Ir3 Definite time limit Settling time t2(S) 0.06 0.1 0.2 0.3
Tolerance (S) ±0.02 ±0.03 ±0.04 ±0.06
Returnable time (S) 0.14 0.21


Operational performance of the circuit breaker

125A, 250A 400A, 800A
Electrical life (maintenance free) 20000 times 10000 times
Electrical life (with maintenance) 40000 times 20000 times
Electrical life 8000 times 7500 times




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