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Anonymous users2024-02-07Formula: n=60f p
Wherein: n - the speed of the motor (revolutions); 60 - constant (60 if n is a revolution, 1 if n is a second);
f - mains frequency (Hz); p – the number of pole pairs of the rotating magnetic field of the motor.
Standards in our country:
China stipulates that the standard power supply frequency is f = 50 Hz (there are mainly 60Hz and 50Hz in the world), so the speed of the rotating magnetic field is only related to the number of pole pairs. The number of pole pairs is large, and the rotational speed of the rotating magnetic field is low.
When the number of pole pairs p=1, the rotational speed of the rotating magnetic field n=3000;
When the number of pole pairs p=2, the rotational speed of the rotating magnetic field n=1500;
When the number of pole pairs p=3, the rotational speed of the rotating magnetic field n=1000;
When the number of pole pairs p=4, the rotational speed of the rotating magnetic field n=750;
When the number of pole pairs p=5, the rotational speed of the rotating magnetic field n=600
In fact, due to the presence of the slip rate, the motor. The actual rotational speed is slightly lower than the rotational speed of the rotating magnetic field) In the variable frequency speed regulation system, according to the formula n=60f p, it can be known:
The rotational speed can be changed by changing the frequency f.
Decrease the frequency f and the rotational speed becomes smaller: ie.
f pn increases the frequency f, and the rotational speed increases: ie.
f pn elaborate:
If the frequency of the three-phase alternating current is 50Hz, the synchronous speed of the resultant magnetic field is 50Rs, i.e. 3000RminIf the rotating magnetic field of the motor is more than a pair of poles, further analysis can also obtain the synchronous speed n
Relation to the pole logarithm p of the magnetic field: n = 60f is the frequency, and the unit of is r min
The frequency of ns and the connected alternating current.
f) There is a strict relationship between the number of pole pairs (p) of the motor.
ns=fp In China, the power supply frequency is 50Hz, so the synchronous speed of the two-pole motor is 3000 rpm, the synchronous speed of the four-pole motor is 1500 rpm, and so on. The rotor of an asynchronous motor always rotates at a speed lower or higher than the speed of its rotating magnetic field, hence the name asynchronous. The difference between the rotor speed of an asynchronous motor and the speed of the rotating magnetic field (called slip) is usually within 10%.
It follows that the speed of an AC motor (whether synchronous or asynchronous) is limited by the frequency of the power supply. Therefore, it is difficult to regulate the speed of AC motors, and the best way is to change the frequency of the power supply, which is more complicated to change the frequency of the power supply in the past. Therefore, before the 70s, DC motors were mostly used on occasions that required speed regulation.
With the development of power electronics technology, the frequency conversion speed regulation technology of AC motors has begun to be put into practice.
Rotational speed of synchronous motor = 60 * frequency
Number of pole pairs (China's power frequency is 50Hz), asynchronous motor speed = (60 * frequency
pole pair) (1 - slip rate).
In addition, the higher the speed of the motor of the same power, the smaller the output torque.
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Anonymous users2024-02-06The formula for the speed and frequency of the motor.
n=60f/p
In the above formula. n - the speed of the motor** minutes);
60 – per minute (seconds);
f - power supply frequency (Hezhi);
p – the number of pole pairs of the rotating magnetic field of the motor.
China stipulates that the standard power supply frequency is f = 50 cycles, so the speed of the rotating magnetic field is only related to the number of pole pairs. The number of pole pairs is large, and the rotational speed of the rotating magnetic field is low.
When the number of pole pairs p=1, the rotational speed of the rotating magnetic field n=3000;
When the number of pole pairs p=2, the rotational speed of the rotating magnetic field n=1500;
When the number of pole pairs p=3, the rotational speed of the rotating magnetic field n=1000;
When the number of pole pairs p=4, the rotational speed of the rotating magnetic field n=750;
When the number of pole pairs p=5, the rotational speed of the rotating magnetic field n=600
In fact, due to the presence of the slip rate, the motor. The actual rotational speed is slightly lower than the rotational speed of the rotating magnetic field) In the variable frequency speed regulation system, according to the formula n=60f p, it can be known:
The rotational speed can be changed by changing the frequency f.
Decrease the frequency f and the rotational speed becomes smaller: ie.
f pn increases the frequency f, and the rotational speed increases: ie.
f↑pn↑
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Anonymous users2024-02-05Synchronous speed n0
60f p, f is the three-phase power supply frequency, p is the number of pole pairs, and the rotor speed ns) n0
s)*60f
p, it can be seen that under the condition of slip rate s and a certain frequency of the power supply, the rotational speed n is inversely proportional to the number of pole pairs.
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Anonymous users2024-02-04The relationship between the number of poles and the speed of the motor: synchronous speed = 120 * frequency number of poles.
Power: Under the same volume, the torque is large with more poles.
The synchronous speed of the AC motor (the same speed as the generator shed silver with the same number of poles).
It can be calculated from the following formula:
n 60 p per minute).
f is the frequency of the power chain and p is the number of pole pairs.
i.e. pole number 2).
Determinants of motor speed:
For synchronous motors or asynchronous motors.
The speed of the motor is related to the frequency of the power supply, the number of pole pairs of the motor is old, the higher the frequency of the power supply, the fewer the number of pole pairs, the higher the speed; In the case of asynchronous motors, it is also related to the current through the electric coil, the higher the current, the closer its rotational speed is to the synchronous speed.
There is also a type of motor (usually AC and DC motors), the speed of which is independent of the frequency of the power supply. It is only related to the magnitude of the current passing through the coil.
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Anonymous users2024-02-03This is the number of poles you have and the logarithm of your poles.
The misunderstanding of Chunzhou is wrong.
2 poles can only count as 1 pair, not 2 pairs. 60s*60hz 1=3600 rpm water pump 3520 normal. Differential 80 is an asynchronous motor.
speed difference.
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Anonymous users2024-02-02The formula you are talking about calculates the rotational speed of synchronization, which is the rotational speed of the magnetic field generated by the three-phase electricity. Negotiation rules.
The practical application of the water pump electric punching machine is an "asynchronous" motor, that is, only when the speed of the motor rotor is lower than the speed of the magnetic field, the rat bar of the rotor can cut the magnetic field lines to produce torque, which is determined by the principle of the asynchronous motor.
This leads to a "slip rate" parameter, the size of which is not the same for different products and different designs.
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Anonymous users2024-02-01p is the pole logarithm. Not the number of poles.
The 2-pole motor is 1 pair, the 4-pole motor is 2 pairs, and the 6-pole motor is 3 pairs ---
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Anonymous users2024-01-31Each turn of the rotor can induce the number of poles that form several periodic current divergences in the guess nucleus turn of the stator coil, and a potential of 50 Hz requires a corresponding divergence speed.
The number of poles reflects the synchronous speed of the motor, and the relationship between the synchronous speed n and the number of pole pairs p in the magnetic field: n=120f p, n is the unit of speed r min, f is the frequency, the unit is hz, p pole. The 2-stage synchronous speed is 3000r min, the 4-pole synchronous speed is 1500r min, the 6-pole synchronous speed is 1000r min, and the 8-pole synchronous speed is 750r min.
The more pole pairs the motor has, the lower the speed of the motor and the greater the torque.
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Anonymous users2024-01-30n=60f/p
In the above formula. n - the speed of the motor** minutes);
60 - per minute (split seconds);
f - power supply frequency (Hezhi);
p - the number of blind return pairs of the rotating magnetic field of the motor.
China stipulates that the standard power supply frequency is f = 50 cycles, so the speed of the rotating magnetic field is only related to the number of pole pairs. The number of pole pairs is large, and the rotational speed of the rotating magnetic field is low.
When the number of pole pairs p=1, the rotational speed of the rotating magnetic field n=3000;
When the number of pole pairs p=2, the rotational speed of the rotating magnetic field n=1500;
When the number of pole pairs p=3, the rotational speed of the rotating magnetic field n=1000;
When the number of pole pairs p=4, the rotational speed of the rotating magnetic field n=750;
When the pole starvation logarithm p=5, the rotational speed of the rotating magnetic field n=600 Actually, due to the presence of the slip rate, the motor. The actual rotational speed is slightly lower than the rotational speed of the rotating magnetic field) In the variable frequency speed regulation system, according to the formula n=60f p, it can be known:
The rotational speed can be changed by changing the frequency f.
Decrease the frequency f and the rotational speed decreases: i.e. 60 f p = n Increase the frequency f, and increase the rotational speed: i.e. 60 f p = n
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Anonymous users2024-01-29Motor synchronous speed = 60 * power frequency number of pole pairs.
It is expressed by the formula n=60f p, where f is the power supply frequency, p is the number of pole pairs, and n is the synchronous speed of the motor.
In China, the frequency of three-phase alternating current is 50, and the 2-pole motor has a pair of magnetic poles inside, and the speed of the magnetic field rotation per minute is 3000, and the synchronous speed is 3000, and the rated speed of the general motor is actually asynchronous speed, which is usually smaller than the synchronous speed.
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