How to calculate the drive current of the motor, and what factors are it related to?

The motor drive current is determined by the motor power because the voltage is designed and cannot be changed. Power voltage = current If it is a three-phase motor, the current 3 = the current of each phase of the motor is related to the actual operating current and the load, and the current must be large when working at full load, and the selected power is calculated according to the rated power.

1. The basic formula of asynchronous motor.

Rated power = * rated line voltage * rated line current * power factor * motor efficiency.

For a 10kw motor in practical application, the product of the power factor and the efficiency of the motor is approximately.

Then the rated line current should be equal to 10kw * 1000 380 =

During the discussion in the evening, a friend in the group proposed that when actually calculating, multiply the power of the motor by 2 to get the current. Of course, it's right from the results, but you also need to know why it's true, right?

2. The concept of line current and phase current.

In fact, I made a big mistake when I was discussing it in the evening, thinking that it was to calculate the phase current, so I also considered the star connection and the triangle connection. At that time, I was working overtime and secretly on QQ, so my mind is not clear, please forgive me! Now when you go back home and sit down, your mind will be clear.

In fact, regardless of whether the motor is a star winding or a triangle winding, the line current on the stator winding is calculated according to the above formula! The question of choosing to open the air raised by the friend at the beginning is only related to the line current!

3. Calculation of starting current and selection of air opening.

Above I basically explained the calculation problem of the rated working current, now back to the original question, how big should I choose? It has been suggested that the size of the switch should be verified by the size of the starting power. But I don't think it's possible, because the starting current lasts very little after all.

Since I work in the power sector, I know very little about the application of asynchronous motors. I hope the master can advise on this issue.

Summary. Hello dear, it is determined by the rated power, rated voltage and power factor of the motor. But the most fundamental reason is the wire diameter of the winding, and the larger the wire diameter, the greater the allowable current.

Hello dear, the plexus review is determined by the rated power, rated voltage and power factor of the motor. But the most fundamental reason is the wire diameter of the winding, and the larger the wire diameter, the greater the current allowed through the world.

The selection of the rated power of the motor is generally mainly considered that the capacity of the motor should be greater than the shaft power of the mechanical equipment it is dragging. If the rated power of the motor is too large, the motor is often in light load operation, and the capacity of the jujube motor itself can not be fully utilized, and the operation efficiency and performance of the motor are low, which will increase the operating cost; The rated power of the motor is smaller than the requirements of the production machinery, the motor current exceeds the rated current, the internal loss of the motor increases, and the efficiency is reduced, the important thing is to affect the life of the motor, even if the overload is not much, the life of the motor will be reduced more; If there is more overload, it will destroy the insulation of the motor insulation material, poor impulse energy and even burn out. The steps of motor rated power selection First calculate the load power, select the rated power of the motor, and then check the heating temperature rise and overload capacity of the selected motor, and check the starting capacity if necessary.

Power (single-phase AC) = voltage * current * power factor.

If three-phase alternating current is used: power (three-phase alternating current) = voltage * current * power factor *.

How much ampere is the current of the water pump, then you must know what the voltage is, and then you must also know what the power code rate factor of the motor is.

Taking the motor power of 9000W as an example, the current of 9000W is introduced at a voltage of 380V and a voltage of 220V.

1. When the voltage is 380V, the current is.

The formula for calculating the power is p 3uicos, and we can calculate the current according to this formula for calculating the power.

The power p in the formula is 9000W, the voltage U is 380V, and the power factor cos is the value of the conventional value as;

Then calculate the current according to the formula p 3ucos, i p 3ucos 9000w 3 380v ;

So, the current required for 9000W of power is:

2. When the voltage is 220V, the current is 48A

Using the formula for calculating power at 220V p uicos, we can also calculate the current according to this power calculation formula.

The power p in the formula is 9000W, the voltage U is 220V, and the power factor cos is still taken according to the convention;

Then calculate the current according to the formula p uicos, i p ucos 9000w 220v ;

Therefore, the current required for 9000W power in a 220V circuit is 48A.

What factors are related to the electromagnetic torque of DC motors. Blind respect.

a.The air gap is magnetically dense.

b.Armature current sparrow.

c.Motor speed.

d.Torque constant.

Correct answer: Air gap magnetic dense; armature current; Torque constant.

1. As long as it can be started, the starting current of the motor has nothing to do with the load.

During the motor start-up process, the maximum current moment occurs before the motor rotates, and before the rotation, the motor is equivalent to a transformer with a short-circuit on the secondary side, and the starting current is independent of the load. Because at this time, the motor is no different from the stalled rotation, since the stalled rotation, no matter how large the load is, it is the same. However, the greater the load and the greater the average current during the period between the start of rotation and the time when the stable speed is reached.

2. The starting current mainly depends on the amplitude and frequency of the applied voltage, under the premise of being able to start, the lower the frequency, the smaller the starting current, the lower the voltage, the smaller the starting current.

The starting current of the motor is mainly related to the load.

The larger the load, the more difficult it is to start, and the more the starting current will be. However, the starting current we usually consider is discussed in the case of no load of the motor, that is, the magnetic field of the motor is stationary relative to the rotor at the moment of starting, so he wants to break this state, at this time, the starting torque is very large, and the random current also increases, so there is the concept of starting current.

The starting current of the motor is mainly related to the power of the motor, usually the smaller the power, the smaller the starting current of the motor. In addition, the starting current is larger when there is a load than when there is no load. If the line voltage drop is too large, the starting current of the motor will be larger, or even unable to start normally.

It is related to the level of line voltage and the weight of the mechanical load.

1. The motor itself (manufacturing reasons).

2. The reason for the machine.

3. Power supply quality.

4. Users.

with the power of the motor as well as the load of the motor.

Proportional relationship, the current increases, the power increases.

The algorithm formula is p=ui, where p is power, u is voltage, and i is current. Version example: When the rated voltage is 220V, it is calculated as:

1. When I=2A, power P=UI=220X2=440W2, I=3A, power P=UI=220X3=660W, wherein, the unit of power is W (watts), the unit of current is A (amps), and the unit of voltage is V (volts).

The relationship between motor efficiency and current.

Electrician formula: power to convert current, keep in mind these 6 formulas, calculate current in 1 second, and you will learn it as soon as you learn it.

The relationship between the power of the motor and the magnitude of the current, and the algorithm! The motor power of 380V is: p(w)=, power factor and efficiency (cos, respectively.

When the motor voltage is 380 volts, it can be calculated by the following formula:

Motor power = 3 current

What is that theorem above? Why haven't you seen it? According to the physics formula, the rated power is equal to the rated voltage and the rated current, of course, there is another way, go to the high school physics book.

1.According to the type of working power supply: it can be divided into DC motor and AC motor.

DC motors can be divided into brushless DC motors and brushed DC motors according to their structure and working principle.

Among them, AC smart pin key motors can also be divided into: single-phase motors and three-phase motors.

2.According to the structure and working principle, it can be divided into DC motors, asynchronous motors, and synchronous motors. Filial piety.

In a three-phase asynchronous motor, a rotating magnetic field is formed between the three phases when the forward power is supplied. This rotating magnetic field causes an inductive action between the stator and the rotor, resulting in a reverse torque. If you want to increase or decrease this reverse torque, you need to adjust the amount of current flowing through the stator coil.

Specifically, in practice, the output power and torque of the drive motor can be controlled by changing the DC bias voltage applied on the AC input port without a rock bench, and adjusting the output frequency and duty cycle of the inverter bridge. In addition, the system can be precisely controlled using automated calculation methods such as PID controllers, and parameters can be adjusted in real time according to different load conditions to achieve the best results.

In short, all kinds of conveyor belts, pumping stations, fans and other equipment commonly found in the industrial field are all used in similar methods to achieve accurate and reliable driving and meet different process needs.

The relationship between the power of the motor and the magnitude of the current, and the algorithm! The motor power of 380V is: P(W)=

Power factor and efficiency (cos, taken separately.

When the motor voltage is 380 volts, it can be calculated by the following formula:

Motor power = 3 current

Starting current refers to the impulse current of electrical equipment (inductive load) at the beginning of starting, is the amount of current change in the motor or inductive load in a short period of time from the moment of power-on to the smooth operation, this current is generally 4-7 times the rated current, the state stipulates that in order to run the line and the normal operation of other electrical equipment, the high-power engine must be equipped with starting equipment to reduce the starting current.

The normal operation of the three-phase motor 1kw is 2A; Three-phase motor 1kw normal operation is.

The relationship between motor efficiency and current.