How to calculate the speed slip rate of three phase asynchronous motor?

Asynchronous motor.

The slip rate is an asynchronous motor.

The ratio of the difference between the speed n and the synchronous speed n0 to the synchronous speed, and the synchronous speed n0 of the motor is calculated by n0=60f p, where f is the grid frequency (the grid frequency in our country is 50hz), and p is the number of pole pairs of the motor.

The motor nameplate will display the number of poles of the motor, this value divided by 2 is the number of pole pairs), the speed of the asynchronous motor n can be measured after the motor is connected to the power supply, which is the actual speed of the motor, that is to say, a parameter is calculated, and the other parameter is the actual value, measured, and then according to the above calculation formula of the slip rate, a calculation can be done.

The slip rate of the asynchronous motor is calculated as follows:

1. First find the synchronous speed n0=60f p, generally f is 50hz, p is the number of pole pairs of the motor.

2. Use the formula to find the slip rate sn=(n0-nn) n0=30 750, where nn is the rated speed of the motor.

Induction motor, also known as "asynchronous motor", that is, the rotor is placed in a rotating magnetic field, and under the action of the rotating magnetic field, a rotating torque is obtained, so the rotor rotates. Rotors are rotating conductors, usually in the shape of a squirrel cage. Invented in 1887 by electrical engineer Nikola Tesla.

Rotational speed = (60F N) (1-S), F is the power frequency 50Hz, N is the number of pole pairs of the motor.

s is the slip rate.

The synchronous speed of an ordinary AC motor can be calculated by the following formula: n f 60s p** per minute).

f is the power supply frequency; p is the number of pole pairs (pole pairs = pole number 2), so the speed of the rotating magnetic field is only related to the number of pole pairs.

The formula for the speed of the three-phase asynchronous motor is: n=60f p(1-s)f represents the power supply frequency, and p is the number of pole pairs, n'represents the slip rate, and s stands for the slip rate.

The speed of the three-phase asynchronous motor is graded and determined by the "number of poles" of the motor. The "number of poles" of a three-phase asynchronous motor is the number of poles in a specified sub-magnetic field. The stator windings are connected in different ways, and different poles of the stator magnetic field can be formed.

The rated coarse speed of the three-phase asynchronous motor is n=60F p(1-s), where n is the rated speed, in r min; f is the power frequency, in Hz; p is the logarithm of the stator winding magnetic pole guess the age of the panicle; s stands for the slip rate.

1. The synchronous speed of the asynchronous motor refers to the alternating current added to the input end of the motor.

The velocity of the rotating magnetic field, which is called the synchronous velocity, is calculated as n 60f p, f: the frequency of the alternating current, and p: the number of pole pairs of the motor.

Taking the domestic power grid 50hz as an example, for the synchronous speed of a 4-pole motor (2 pairs) 60 50 2

1500rpm。

2. The rotor speed of the asynchronous motor is equal to the synchronous speed under the theoretical no-load, but it is impossible to do it in practice. The difference between the two is the slip velocity, which is divided by the synchronization velocity to get the slip rate.

The larger the load, the smaller the rotor speed and the greater the slip rate. In practice: motor nameplates.

The speed on is the rotor speed.

Three-phase asynchronous motor.

Synchronize the speed with the number of poles of the motor.

Related: 2 motors synchronous speed of 3000 rpm.

4. The synchronous speed of the motor is 1500 rpm.

6. The synchronous speed of the motor is 1000 rpm.

8. The synchronous speed of the motor is 750 rpm.

The rated speed is related to the motor slip rate, and the slip rate varies from one manufacturer to another, generally around 4. For example, the rated speed of a 4-pole motor is generally around 1440 rpm.

When a pair of poles are paired, the synchronous speed is the conversion of the alternating current frequency into minute revolutions.

That is, 50x60 = 3000 revolutions.

When it is multiple pairs of poles, the synchronous rotational speed = 3000 pole pairs. For example, the number of pole pairs is 2 synchronous speed = 1500

s=60f/n

S --- synchronous speed.

n--- pole logarithms.

f--- mains frequency.

60--- a minute.

The grid frequency of 50Hz is equivalent to 3000 rpm for 2-pole motors, 1500 rpm for 4-pole motors, and the synchronous speed is based on the number of poles of the motor, and so on.

Depending on the number of poles of the motor, the lower the number of stages, the higher the speed, and vice versa.

The synchronous speed of a three-phase asynchronous motor can be calculated by the following formula:

n=60f/p

where n is the synchronous speed (unit: revolutions), f is the power frequency (unit: hertz), and p is the number of pole pairs of the motor.

For example, if the power frequency is 50Hz and the number of pole pairs of the motor is 2, the synchronous speed is:

n = 60 50 2 = 1500 rpm min.

It should be noted that the actual speed of the three-phase asynchronous motor will be affected by a variety of factors, such as rotor resistance, rotor leakage inductance, load, etc., so there is a certain difference between the actual speed and the synchronous speed.

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The rated speed is 1442r min

Slip rate: 1> number of pole pairs: p 60f n 60 50 1442 2 (pairs).

2> Synchronous speed: N1 60F P 60 50 2 1500***

3> Slip rate: s (n1 n) n1 100 (1500 1442) 1500 100

The ratio of the difference between the speed n of the asynchronous motor and the speed n0 of the synchronous motor to the speed of synchronization. When s=(n0-n) is not large, it is proportional to the output power or torque of the motor.

The stator winding is passed through the three-phase alternating current to produce a rotating magnetic field, the rotating magnetic field cuts the rotor conductor and generates an induced electromotive force, and the induced electromotive force is generated in the closed circuit of the conductor, and the rotor current and the stator magnetic field interact with each other to produce electromagnetic force and drive the rotor to rotate, and the direction of rotation is consistent with the direction of the stator's rotating magnetic field.