Magnetic field circuit breaker DM8G-400/800 20

Introduction to DM8G Series Circuit Breaker

1 Purpose and conditions of use

1.1 The DM8G magnetic field circuit breaker is suitable for use as a demagnetization protection circuit breaker in the main excitation circuit of generators with a rated voltage of DC800V and below, and a rated current of 6300A and below, when combined with nonlinear resistors. Alternatively, it can be combined with appropriate constant resistance to form a demagnetization combination device for generators, suitable for excitation circuits of 600000 kilowatts and below with rated voltage of DC 500V and below and rated current of 6300A and below, for demagnetization protection. In addition, it can also be used to disconnect excitation circuits under no-load or rated load, or to carry and disconnect other DC circuits.

1.2 Normal usage conditions

1. 2. 1. Altitude not exceeding 2000m;

1. 2. The ambient air temperature is between -5 ℃ and+45 ℃;

1. 2. 3 Atmospheric conditions: The average relative humidity in wetter months is not greater than 90%, and the average lower temperature in that month is 25 ℃;

1. 2. The pollution level of the circuit breaker is Class III when it is in a medium without explosive hazards and without gases and dust (including conductive dust) that can corrode metals and damage insulation.

1. 2. During installation, the inclination relative to the horizontal plane should not exceed 5 °.

2 Technical parameters

2.5 Product Model and Its Meaning

Note: 1) 1/0- is a pair of normally open main contacts;

1/1- A pair of normally open main contacts with a pair of normally closed auxiliary contacts;

a. Cleaning function. All contacts and conductive copper parts are coated with DJB-823 solid film protective agent on their surfaces, which can protect their surface from oxidation and ensure good contact performance.

b. When the metal grid arc extinguishing chamber is disconnected, it can generate a sufficiently high and stable arc voltage, which is sufficient to conduct ZnO nonlinear resistors or other resistors for professional demagnetization.

c. By using permanent magnet steel to generate a blowing arc magnetic field and eliminating the blowing arc coil, even under low current conditions, it can professionally cut off the current.

d. The opening and closing actions of normally open and normally closed contacts are completed by the rotation of the same shaft. As long as the opening distance of the contacts reaches the required value, the normally closed contacts of the circuit breaker can be kept closed first and then opened after the normally open contacts; When closing, the normally open contact is closed first, and the normally closed contact is opened later. The overlap time is (4-5) ms. The diagram of the normally open contact system is shown in Figure 2.

2/0- Two pairs of normally open main contacts;

2/1- Two sets of normally open main contacts with one set of normally closed auxiliary contacts.

3 Structure and Working Principle

3.1 This series of magnetic field circuit breakers is a maintainable frame type magnetic field circuit breaker. The magnetic field circuit breaker is arranged in a three-dimensional form, so it has a compact structure, small volume, light weight, strong series, and high technical and economic indicators.

The structure of the 3.2 magnetic field circuit breaker is shown in Figure 1 and Figure 3.

3.3 Closing of magnetic field circuit breakers

The magnetic field circuit breaker uses an electric motor for closing, with a rated control voltage of DC220V. The required power is shown in Tables 1, 2, and 3.

3.4 Disconnecting of magnetic field circuit breakers

The magnetic field circuit breaker adopts a shunt release for tripping, with a rated control voltage of DC220V. The required power is shown in Tables 1, 2, and 3.

The wiring terminal positions of the control circuit of the 3.5 magnetic field circuit breaker are shown in Figure 4.

The operating principle diagram of the 3.6 circuit breaker is shown in Figure 5.

Refer to Figure 6 for the wiring diagram of the 3.7 circuit breaker terminal block.

4 Installation and use

Before installation, check whether the specifications of the magnetic field circuit breaker meet the requirements.

When installing the 4.2 magnetic field circuit breaker, its appearance and installation dimensions are shown in Figure 6 and Figure 7.

4.3 The top of the arc extinguishing chamber should maintain a flying distance of 200mm, and both sides should maintain a distance of 100mm. If the size is smaller than the above, an insulation partition should be installed.

The M12 grounding screw marked with a grounding symbol on the circuit breaker must be professionally grounded.

5 Maintenance and Overhaul

Magnetic field circuit breakers must be inspected and regularly maintained during operation.

5.1 Clean the dust to maintain good insulation of the magnetic field circuit breaker.

5.2 Add lubricating oil to each rotating or sliding part.

5.3 Check the contact system

5. 3. Wipe off the smoke marks on the contact, and if small metal particles are found on the contact surface of the contact, they should be removed.

5. 3. If the thickness of the silver alloy contact is less than 1mm, the contact must be replaced.

5. 3. When the dynamic and static contact arc contacts first come into contact and the distance between the dynamic and static main contacts is less than 2mm, the contact must be adjusted.

After the magnetic field circuit breaker is subjected to short-circuit current, in addition to checking the contact system, it is necessary to clean the smoke marks on both walls of the arc extinguishing chamber; If the arc extinguishing grid is severely burned, the arc extinguishing chamber should be replaced.

6 spare parts

Spare parts for circuit breakers shall be supplied according to the contract.

7 Ordering precautions

(2) 7.1 The model, specifications, quantity, rated operating voltage, and delivery deadline must be specified in the order contract. The electromagnetic system adopts a spiral tube electromagnet with electromagnetic closing, permanent magnet holding, and demagnetization opening, which has no mechanical wear, professional operation, and long service life. The electromagnetic system and normally closed contacts are shown in Figure 3.

One DM8G-800/500-2/1 magnetic field circuit breaker, to be delivered within 20 days.

7.2 If there are special requirements for ordering, they must be agreed upon by both the supply and demand parties in advance and detailed in the contract.

8 Other

If there are any changes, there will be no additional deadline, and the random instruction manual shall prevail.

Figure 1 DM8G-200, 400A/800-2/1

Outline structure diagram of magnetic field circuit breaker

Figure 2

DM8G-200、400A/800-2/1

Assembly position number of each component of the magnetic field circuit breaker

1. For auxiliary switch DF

2. Terminal block

Figure 3

DM8G-400、630、800、1000、1600、2500A/ □—□

Outline structure diagram of magnetic field circuit breaker

Figure 4

DM8G-400、630、800、1000、1600、2500A/ □—□

Assembly position number of each component of the magnetic field circuit breaker

1. For auxiliary switch DF

2. Terminal block

Figure 5 Schematic diagram of circuit breaker operation

HC: DC contactor

HJ: DC Relay

D: Electric motor coil

TQ: Circuit breaker trip coil

DF: Circuit breaker auxiliary switch

HA: Closing button

TA: Open button

Figure 6 Circuit Breaker Terminal Block Diagram

Figure 7

DM8G-200、400、630、800、1000、1600、2500A/ □—□

Dimensions and installation dimensions of magnetic field circuit breakers

Table 1 Technical parameters of magnetic field circuit breakers without normally closed secondary contacts

Table 2 Technical parameters of magnetic field circuit breakers with normally closed secondary contacts

Note: When the magnetic field circuit breaker is disconnected, the normally closed auxiliary contact should be closed first, and then the normally open main contact should be disconnected.

Table 3 Technical parameters of magnetic field circuit breakers with normally closed secondary contacts

9 Special Disclaimer

9.1 The magnetic field circuit breaker with a rated current of 400A has a ground type structure, namely high voltage building capacity (single break ≥ 1400V) and low voltage building capacity (single break ≥ 500V). The magnetic field circuit breaker with a rated current of 200A only has one low voltage building capacity structure. Magnetic field circuit breakers with a rated current of 630A and above have only one high voltage building capacity structure.

Mainly determined by the structure of the arc extinguishing hood.

The operating system mechanism of the DM8G series magnetic field circuit breaker adopts the ME series circuit breaker structure. Adopting a new arc extinguishing system with high voltage building capability.