Communicate the principle of AC contactors.
When the coil is plugged in, the iron core of the static transformer causes the eddy current adsorption force to digest and absorb the iron core of the dynamic transformer. Because the contact point system software is connected with the moving transformer iron core, the moving transformer iron core pushes the three moving contact points at the same time, the main contact closes, assists the normally closed contact to break, assists the normally closed point to close, and connects the switch power supply.
When the coil is powered off, the adsorption force subsides, and the connecting part of the iron core of the moving transformer is separated by the recoil force of the torsion spring, breaking the main circuit breaker, and the auxiliary normally closed contact connected with the main contact point sleeve is closed to assist the normal closed contact. The closing point is broken, and the switching power supply is disconnected.
The communication contactor is only used to communicate the communication route. If the AC contactor must be connected to DC, the conclusion must be that the route and even the machinery and equipment are severely damaged.
A key component of the communication contactor.
(1) Electromagnetic induction system software, including attracting coils, moving transformer iron cores and static iron cores;
(2) The circuit breaker system software includes three groups of main circuit breakers and one to two groups of on and off. The normally closed auxiliary circuit breaker is connected to the iron core of the moving transformer;
(3) Magnetic blowing equipment, generally large-capacity AC contactors are equipped with magnetic blowing equipment, which is convenient to quickly disconnect the electric isolation and prevent the main circuit breaker from being burned;
(4) Insulation layer casing and accessories, various springs, transmission mechanisms, short-circuit fault rings, terminals, etc.
Communicate the wiring method of the AC contactor.
There is a logo on the contactor (based on reality)
1L3L5L, which corresponds to 2T4T6T, is the key interface.
The corresponding coils have terminals A1A2.
Auxiliary contacts can be matched.
13.14 indicates the auxiliary contact of the contactor, NO indicates on and off, that is, 13.14 is disconnected without plugging in, and 13.14 is turned off after plugging in. Self-locking (and connected to the running button) is placed in a part of the control loop to achieve the purpose of continuous operation.
Communication AC contactor wiring diagram.
Adjust the motor reversible operation control loop.
1. Check whether the wiring of the main circuit is correct. In order to ensure that the two contactors can reliably replace the neutral live wire of the motor when they are moved, the outer wiring of the contactor should be consistent and adjusted in the lower hole of the contactor.
2. After checking that the wiring is correct, a plug-in experiment should be carried out. To avoid casualties, disconnect the motor wiring first. Preparing for common fault conditions;
1. No operation; one of the reasons is to check whether the commercial insurance FU is short-circuited, whether the FR connector of the thermal relay is used incorrectly or has poor contact, and whether the normally closed connector of the SB1 button is not good. The second factor is the incorrect wiring of the key self-locking interlock.
2. During operation, the contactor does not suck; this is because the normally closed contact of the contactor is incorrectly connected to the self-locking interlock, and the self-locking and interlocking touch is self-locking. In operation, the normally closed contact surface is the electrical suction contactor of the contactor coil. After the contactor coil is powered off, the contactor coil is de-energized and released, the normally closed contactor is released, the contactor is sucked in again, and the contactor is cut off again. Thus, the contactor is not easily sucked in.
3. The self-locking contactor cannot be disconnected. This is due to the incorrect wiring of the self-locking contact and the reversible operation of the motor. In order to better enable the motor to rotate forward and reverse, two contactors KM1.KM2 motor three The phase power supply neutral wire is the live wire, but the two contactors cannot be digested and absorbed. If digested and absorbed at the same time, it will cause a power supply short-circuit safety accident. In order to avoid safety accidents, the power supply circuit should use a reliable self-locking interlock.
The route anatomy looks like this:
1. Running in the positive direction:
1. Turn off the air leakage switch QF and connect the three-phase power supply.
2. Press and hold the forward running button SB3, KM1 is plugged in, pulled in and self-locking, and the main circuit breaker is closed and closed to connect the motor. At this time, the neutral wire of the motor is L1.L2.L3, that is, it operates in the positive direction.
2. Running in the opposite direction:
1. Turn off the air leakage switch QF and connect the three-phase power supply.
2. Press and hold the operation button SB2 in the opposite direction, KM2 is self-locking according to the auxiliary contact, often turn off the main contact, and replace the neutral wire and live wire of the three-phase power supply of the motor. At this time, the zero line of the motor is L3.L2.L1, that is, it operates in the opposite direction.
3. Self-locking and interlocking stage: It has a strictly forbidden function and has a safety guarantee effect in the distribution line.
1. Contactor self-locking and interlocking: the KM1 coil control loop is connected in series with the KM2 normally closed auxiliary contact, and the KM2 coil loop is connected in series with the KM1 normally closed contact. When the forward rotation contactor KM1 coil is plugged in, KM1 assists the normally closed contact to cut off the KM2 coil control circuit. If KM1 is plugged in and pulled in, KM2 must first turn off the power and release it to assist in the calibration of the normally closed contacts to avoid two-color short-circuit faults caused by KM1 and KM2 being pulled in at the same time. This route stage is called the self-locking and interlocking stage.
2. Button self-locking and interlocking: the positive and negative poles of the actual operation of the control button are transmitted to the control loop for the power supply circuit. The buttons SB2.SB3 have a pair of normally closed points and a pair of normally closed contacts, which are respectively connected with the KM1.KM2 coil power circuit.
For example, the normally closed point of the button SB2 is connected in series with the coil of the contactor KM2, and the normally closed contact is connected in series with the power circuit of the coil of the contactor KM1. The normally closed point of the button SB3 is connected in series with the coil of the contactor KM1, and the normally closed contact is connected in series with the power circuit of the KM2 coil. That way, when SB2 is held down, only the contactor KM2 coil can be plugged in, and KM1 turns off the power. When SB3 is pressed, only the contactor KM1 coil can be plugged in, and KM2 is powered off. If SB2 and SB3 are held down at the same time, both contactor coils cannot be plugged in. This works as a self-locking interlock.
4. After the motor runs in the forward direction (or reverse direction), it is not necessary to press the stop button to terminate the motor, but press the reverse direction (or forward direction) operation button at the same time to make the motor run in the reverse direction.
5. The overvoltage protection of the motor is carried out by the thermal relay FR.
Post time: Apr-20-2022
