18 5kw motor with multi large AC contactor

The motor is generally started with step-down, and an AC contactor of 40A-60A can be used.

If it is a direct start, a 100A AC contactor should be used.

The AC contactor is mainly composed of four parts: (1) electromagnetic system, including suction coil, moving iron core and static iron core; (2) The contact system, including three groups of main contacts and one to two groups of normally open and normally closed auxiliary contacts, which are connected with the moving iron core and linked with each other; (3) Arc extinguishing device, the AC contactor with large capacity is generally equipped with an arc extinguishing device, so as to quickly cut off the arc and avoid burning out the main contact; (4) Insulated shells and accessories, various springs, transmission mechanisms, short-circuit rings, binding posts, etc.

The motor is completely sufficient to start directly with CJX2 50A If you want to be safe, you can also use 65A Chint Group's contactor feels better, economical, and the quality is also good.

You can do it this way:

The current of 1 kilowatt of a 380v motor is 2 amps. This means that there is an operating current of 37A.

The AC contactor is selected in the unit of current, and the rated current of the AC contactor is 1-2 times greater than the operating current of the motor.

The model we generally use Huatong CFC2-40.

What size contactor is used for motors? The configuration method is taught to you, and the electrician can configure it.

.The current of the 5kw motor is about 37A, and its rated current refers to the current that occurs when the electrical equipment is running at the rated voltage, indicating that the electrical facilities can work continuously for a long time under the conditions of rated environment, temperature, sunshine and installation, and during normal operation, the current of the electrical appliance can not exceed its rated current

2. What to pay attention to when using a small motor.

Before disassembly, use compressed air to blow off some dust on the surface of the motor and remove some dirt on the surface. When choosing a work site where the motor is dismantled, it is also necessary to clean the site environment. At the same time, it is also necessary to be familiar with the structural characteristics and maintenance technical requirements of the motor.

Generally, the starting current of the motor is 3 7 times of the working current, which affects the working life of the contactor.

Since the frequency of three-phase alternating current in China is 50Hz, the synchronous speed of 2 poles is 3000r min, the synchronous speed of 4 poles is 1500r min, the synchronous speed of 6 poles is 1000r min, and the synchronous speed of 8 poles is 750r min. These speeds are only the synchronous speed of the various pole motors, not the actual speed.

Existential relationship: n=60f p n: motor speed; 60: 60 seconds ; F: China's power supply frequency is 50Hz; p: Number of pole pairs of the motor.

1 pair of pole logarithmic motor speed: 3000 rpm; 2 pairs of pole logarithmic motor speed: 60 50 2 = 1500 rpm.

With the same output power, the more pole pairs the motor has, the lower the speed of the motor, but the greater its torque. Therefore, when selecting a motor, consider how much starting torque is required for the load.

It depends on the three-phase motor? Or a single-phase motor?

If it is a three-phase motor, the working current is about 3A, and the minimum model current of the commonly used CJX2 series contactor is 9A, that is, CJX2-0910, just use this model.

If it is a single-phase motor, that is, a 220V power supply motor, the working current is about A, if you use CJX2 contactor, the model is CJX2-1210; If you choose CHINT NCH8 series, use NCH8-20 20.

The motor has only 3-4A current, and 9A can be selected, which is the minimum specification.

The current of the 15kw motor should be about 30A, so the contactor should be greater than the current, and the domestic contactor should generally leave a certain margin, so you can choose a 40A contactor, if it is more reliableContactor 65A is optional.

Control principle. In order for the motor to rotate, the control department must turn on (or off) the power transistor in the inverter according to the position of the motor rotor sensed by the hall-sensor, and then according to the stator winding, so that the current flows through the motor coil in order to generate a forward (or reverse) rotating magnetic field, and interacts with the magnet of the rotor, so that the motor can rotate clockwise and counter-clock.

When the motor rotor rotates to the position where the hall-sensor induces another set of signals, the control unit turns on the next set of power transistors, so that the circulating motor can continue to rotate in the same direction until the control department decides to stop the motor rotor and then turn off the power transistors (or only open the lower arm power transistor); If the motor rotor is reversed, the power transistor is turned on in the opposite order.

Three-phase electric, 15kw motor, rated current approximately: i=15 (about.)

Air circuit breaker selection: times) 63a

AC contactor selection: 40A

The current is calculated first, and the rated current of the contactor is selected according to the current.

The power factor is calculated.

Power Voltage Root No. 3 Power Factor.

The selection requirements of the contactor are selected according to the multiple of the load current, and the AC contactor of 18A can be selected for the load.

The rated voltage is 380 volts of three-phase asynchronous motor in theory CJT1-20A and CJX2-2510 can be, in fact, it is mainly to see whether the frequent start, the surrounding environment, the installation size and so on to choose the contactor contact capacity and contactor model, and the quality of the contactor is different, using CJT1-40A or CJX2-3210 contactor.

Summary. How big does a motor need to be AC contactor, a motor needs to be equipped with 32 amps or 40 amps AC contactor, which is the choice in the case of a power supply voltage of 380 volts, if the power supply voltage is 220 volts, you need to choose a 60 amp AC contactor, I hope it can help you. <>

How big an AC contactor is needed for a motor.

A motor needs to be equipped with a 32 amperes or 40 amps AC contactor, which is the choice in the case of a power supply voltage of 380 volts, if the power supply voltage is 220 volts, you need to choose a 60 amperes AC contactor, I hope it can help you. <>

How big is the working current of a 2 kilowatt, 22o volt single-phase motor, and how big is the AC contactor.

How much is the working current of a 2 kilowatt, 22o volt single-phase motor, how big is the AC contactor, you can use an AC contactor of more than 10A, and the working current of 2 kilowatts of 220V single-phase motor is about 9A, and the installed cross-ridge excavation flow contactor must be greater than the motor working current. Hope it helps. <>

22kw electric sales of 80 or 100A contactors.

First of all, the current value is calculated according to the motor power, and the three-phase 380V asynchronous motor can be estimated according to the current of 2A per kilowatt, that is, the number of kilowatts multiplied by 2 equals the current value, and the rated current of this 22KW motor is about 44A. The current value of the circuit breaker and contactor is then determined according to the motor current.

If a small (miniature) circuit breaker is used, the D-type should be used, and the current value should be within a multiple of the rated current of the motor. If an ordinary molded case circuit breaker is selected, the current value is greater than or equal to the multiple of the motor amount and constant current.

Basis for selection:

The starting current of the asynchronous motor is 5-7 times of its rated current, in fact, this only means that the bending is the steady-state starting current, which is called the stalled rotor current in the technical parameters of the motor. There is a peak current at the moment when the motor is energized, also called the closing inrush current, and its maximum value is 2 times of the stalled rotor current, that is, 14 times of the rated current.

Therefore, when selecting a circuit breaker, it must be able to avoid this 14 times the starting peak current, otherwise the circuit breaker will trip as soon as it is moved. The D-type in the DZ series of miniature circuit breakers has a short-circuit instantaneous action value of 10-14 times the rated current, so the D-type circuit breaker within the rated current times of the motor is selected, and its instantaneous action value is greater than 14 times the rated current of the motor to ensure that it does not trip during the start-up process. <>

80 or 100A contactors for 22kw motors.

1. Calculate the rated current.

i=p 2, the thermal relay is selected according to the times of the rated current, and the 50A one is selected.

3. The molded case circuit breaker is selected according to the range of times to 2 times of the rated current, and 60 or 80A is selected.

4. The AC contactor is selected according to about 2 times of the rated current, and the one of 80 or 100A is selected.

20A AC contactor should be selected.

The AC motor is working normally, the air switch should use 20A, if it is started frequently, it should also be amplified and added to 32A; Contactor, 20A is fine, if it feels small, the same can be enlarged to 25A.

Contactors are divided into AC contactors (voltage AC) and DC contactors (voltage DC), which are used in electricity, distribution and electricity occasions. Contactor in a broad sense refers to the lap chain electrical appliance that uses the current flowing through the coil to generate a magnetic field and close the contact to control the load in industrial electricity.

Thermal relays use 25A or 32A, as for the cable, in general, the square millimeter is sufficient, if you want to bend the branch better and safer, 4 square millimeters can also be selected.