What are the daily inspections of intermediate relays and contactors? Be specific

Item Summary Inspection Interval Initial inspection 1, confirm whether the power supply specifications are correct 2, confirm the capacity specifications of the main circuit, auxiliary hoe and operating wire coil 3, check whether the terminal lock wire is fixed, and whether there are foreign objects such as wire shaving, iron filings, and dust attached 4, after the power supply is disconnected, try to press the movable part by hand to confirm whether there is any abnormality in the sliding 5, confirm the wiring, try the operation in the state without load, check whether there is any abnormality 6, test the action after adding the load, and check whether there are abnormal phenomena such as abnormal sound, discoloration and expansion, smoke and odor During the commissioning, daily inspection 1, external inspection for abnormal sounds, odors, damage and other abnormal phenomena 2, when abnormalities are found, it is necessary to confirm the abnormal location and degree of abnormality 3, eliminate abnormal phenomena that will directly cause poor function 1 time 1 day 1 month regular inspection 1, in principle, in the state of no power, the implementation of various confirmation inspections 2, the wear of the hoe and the arc extinguishing chamber and other abnormal inspections 3, check whether the nuts are tightly fixed 4, press the movable part by hand to confirm whether there is any abnormality in the sliding 5, when the AC contactor is used for more than 10 years, The inspection interval should be shortened according to the actual situation 1 time Half a year 1 time Two years Detailed inspection 1, in the state of no power, decomposition and renovation of specific parts 2, if necessary, collect samples and discuss with the manufacturer 3, every 3 5 times after the regular inspection of 1 detailed inspection - temporary inspection 1, after the daily and regular inspection, when it is necessary to do a more detailed inspection, or in the event of a failure 2, this inspection can be negotiated with the manufacturer at any time.

1) Whether there is oil, hair, or foreign matter on the contact.

2) Long-term use, whether the surface of the contact is oxidized.

3) Whether there are defects, burrs or metal chips formed by arc ablation.

4) Whether there is any jamming phenomenon in the moving part.

The main maintenance of each electric shock, pay attention to fastening the inlet and outlet lines, and pay attention to the observation of auxiliary contacts for contactors with frequent contact, and the general damage is basically auxiliary contacts or rectifier bridges.

1. Similarities:

The working principle is the same: the opening and closing of the contacts is driven by the electric or non-electric power of the control coil to open or turn on the circuit. The control circuit of the coil is electrically isolated from the electrical circuit where the contacts are located.

2. Differences:

1. Different functions: the AC contactor can be directly used to connect and cut the AC circuit with load; Intermediate contactors are mainly used to reflect control signals.

2. Different contacts: the contacts of AC contactors are divided into main and auxiliary, while the contacts of intermediate relays are not divided into main and auxiliary, and there are many of them.

3. Different structures: AC contactors generally have arc extinguishing devices, but intermediate relays do not. The principle of the intermediate relay is the same as that of the AC contactor, but the contact capacity is smaller, generally not more than 5A; For the electrical control system with the rated current of the motor not exceeding 5A, it can be used instead of AC contactor.

Differences: Contactors are used to turn on or off loads with high power, and are used in (power) main circuits, where the main contacts may have interlocking contacts to indicate the opening and closing state of the main contacts. Intermediate relays are generally used in electrical control circuits to amplify the contact capacity of miniature or miniature relays to drive larger loads.

For example, the contacts of the intermediate relay can be used to turn on or off the coil of the contactor. Generally, intermediate relays and old electrical appliances have more opening and closing contacts, of course, intermediate relays can also achieve some special functions through appropriate connections, such as logical operations. Compared with the contactor, the number of contacts of the intermediate relay is more than that of the contactor, which is mainly used for signal conversion of small current and does not participate in the direct control of the main circuit.

Similarities: Both of them drive the open-nucleus fission and closing of the contacts by controlling the power or absence of electricity in the coil to disconnect or turn on the circuit. The control circuit of the coil is electrically isolated from the electrical circuit where the contacts are located.

The contactor is mainly used in the main circuit, and its working state is determined by the intermediate relay or other control factors. The load capacity of the source closed contact is relatively large.

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Intermediate Relay: Used in relay protection and automatic control systems to increase the number and capacity of contacts. It is used to transmit intermediate signals in control circuits.

The structure and principle of the intermediate relay are basically the same as that of the AC contactor, and the main difference with the contactor is that the main contact of the contactor can pass through a large current, while the contact of the intermediate relay can only pass a small current. Therefore, it can only be used in control circuits.

It generally does not have a main contact because the overload capacity is relatively small. Therefore, all of the contacts it uses are auxiliary contacts, and there are more of them. The definition of intermediate relay in the new national standard is K, and the old national standard is Ka.

Generally, it is powered by DC power supply. A few use AC power.

The structure and principle of the intermediate relay are basically the same as that of the AC contactor, and the main difference with the contactor is that the main contact of the contactor can pass through a large current, while the contact of the intermediate relay can only pass a small current. Therefore, it can only be used in control circuits.

Both of them operate through the principle of electricity to generate magnetism, usually AC contactors control large currents, intermediate relays control small currents, but the number of contacts is large. There is also a traditional habit, some of which are called relays at the beginning, and later people can only follow them.

Same: The opening and closing of the contacts are controlled by the control coils.

Different: The current carrying capacity is different, and the current carrying capacity of intermediate relays is generally within 10A.

AC can carry a large load, but not in the middle, intermediate relays are generally used as extended signal points.

Similarities: 1, they work the same way.

2. They all have, normally open, normally closed.

Differences: 1. Relay, often used for intermediate signal conversion, the contact current is not large, intermediate relay contact teaching more, used to control contactors, often used for signal conversion.

2. Contactor, used to control the actual load, because the contactor main contact, the current flowing through, can be very large, such as controlling motors, heaters, etc.

1.Looking at the contacts of the two, the main difference is: the main contacts that contact the mu noise device are larger, the number is small, and it can pass through a large current; The contact of the intermediate relay generally does not have a main contact, because the overload can be quickly served by Bu Xin is relatively small.

Therefore, all of the contacts it uses are auxiliary contacts, and there are more of them. 2.Intermediate Relay:

It is used in relay protection and automatic control systems to increase the number and capacity of contacts. It is used to transmit intermediate signals in control circuits.

Intermediate relay is a kind of voltage relay, its control capacity is smaller than that of mega mill, the number of contacts is more, used for intermediate control, conversion. The control capacity of the contactor is relatively large, and it is mainly used for control objects such as electric command machines, and the number of contacts is relatively small.

It has many control methods, including electromagnet, pneumatic, hydraulic drive, etc. They are interchangeable and can be used interchangeably when the control current of the control line is less than 10A.

1) Measure the resistance of the coil.

2) The operating voltage (current) and return voltage (current) test can be replaced by the whole group test of 80% of the rated voltage during regular inspection.

3) Relays with more than two coils should be checked for the correct selling of the polarity between the coils, and the insulation resistance between the two coils (excluding external wiring) should be determined

4) Maintain the voltage (current) value, which should be consistent with the specific circuit wiring requirements. The maximum possible voltage drop of the current holding coil in the actual circuit should be less than 5% of the rated voltage of the circuit.

5) Measurement of action (return) time. This test is carried out only for relays that require the operation (return) time of the protection circuit, outlet intermediate relays and anti-jumping relays. The intermediate relay used for the protection of ultra-high voltage power grid, which directly acts on the circuit breaker tripping, should have an action time of less than 10ms.

The action current of the anti-jump relay should be adapted to the action current of the trip coil of the circuit breaker. For the same actual circuit breaker trip current, the operating time of the relay should be less than the conversion (disconnect on trip) time of the auxiliary contact of the circuit breaker in the trip circuit. During the periodic inspection, the operation time of the outlet middle and the anti-jumping relay is checked together with the entire set of tests of the device.

6) Check and observe the working condition of the contact under the actual load state.

7) Reed relays (contacts are directly connected to the V DC voltage circuit) and sealed intermediate relays should measure the insulation resistance between the contacts (normally open contacts when the relay is not operating and normally closed contacts that are lifted after operation) with a 1000V rocking meter.

Intermediate relays are mainly used as control circuits, so the contact capacity is small, and the general contact capacity is less than 5 amperes. The overall volume is also smaller. There is no distinction between primary and auxiliary contacts.

The contactor is larger in size, with main and auxiliary contacts, the main contact capacity is larger, often reaching tens of amperes, and is equipped with a high-temperature arc suppression cover to eliminate the arc pull when the circuit is disconnected. The auxiliary contact has a small capacity and is located in a low position on both sides of the main contact.

At its simplest, the intermediate relay can be divided into two parts, the base and the contact part.

But the contactor is one and cannot be separated.

Intermediate relays generally have more contact groups, and they are all the same. The contactor is usually a three-phase main circuit, with an additional auxiliary contact, which is different from the main contact.

The intermediate relay load will not be greater than 5A, and the contactor is generally greater than 20A