How To Connect The Axial Flow Fan With 4 Wires?

Unit axial flow fan, rated voltage 220. There are four wires, one is yellow and green ground wire, and how to connect the other three? Baidu said to connect capacitors, but how many capacitors? No capacitor. Why connect the capacitor? First of all, why should I connect the capacitor with you?
Your motor must be asynchronous motor, that is, induction motor. The principle of induction motor is to place the rotor in the rotating magnetic field, and obtain the rotating torque under the action of the rotating magnetic field, so as to make the rotor rotate.
As we all know, three-phase alternating current is three alternating currents with the same frequency, equal potential amplitude and 120 ° phase difference. If these three alternating currents enter the pre-designed winding coil, it can form a rotating magnetic field.
Alternating current and rotating magnetic field
This is probably what it means. A picture not only reflects the three-phase alternating current, but also reflects how the three-phase alternating current generates a rotating magnetic field in the coil. Under the action of this rotating magnetic field, the rotor generates an induced current, and then generates a rotating induced magnetic field. The induced magnetic field in the rotor interacts with the induced magnetic field in the stator to generate electric power to promote the rotation of the rotor.
So why does single-phase induction motor need capacitance?
From the perspective of unidirectional alternating current, single-phase alternating current is only a sinusoidal alternating current. No matter how the coils are arranged, they can only produce strong and weak magnetic fields, but not alternating magnetic fields.
In the AC motor, when the stator winding passes through the AC current, the armature magnetomotive force is established, which has a great impact on the energy conversion and operation performance of the motor. Therefore, the single phase AC winding enters the single phase AC to generate the pulse vibration magnetomotive force, which can be decomposed into the sum of two rotating magnetomotive forces with equal amplitude and opposite speed, thus establishing the sum of positive and reverse magnetic fields in the air gap. These two rotating magnetic fields cut the rotor conductor and generate induced electromotive force and induced current in the rotor conductor respectively.
The interaction between current and magnetic field produces positive and negative electromagnetic torque. Positive electromagnetic torque attempts to make the rotor rotate forward; Anti-electromagnetic torque attempts to reverse the rotor. The combination of these two torques is the synthetic torque that drives the motor to rotate.
The relationship between its size and slip rate is the same as that of three-phase asynchronous motor, whether it is a forward or reverse magnetic field. If the motor speed is n,
For the forward rotating magnetic field, the slip is: s+=(n1 - n)/n1=s
For the reverse magnetic field, the slip is: s=(- n1 - n)/- n1=s
How to connect the axial flow fan with 4 wires?
From the formula, we can see that the main characteristics of single-phase asynchronous motor are:
(1) N=0, s=1, T=T++T=0, indicating that the single-phase asynchronous motor has no starting torque. If no other measures are taken, the motor cannot start.
(2) When s ≠ 1, T ≠ 0, T has no fixed direction, which depends on the positive and negative of s.
(3) Due to the existence of reverse torque, the resultant torque is also reduced, so the overload capacity of single-phase asynchronous motor is low.
Working principle of capacitive split-phase starting
When starting, the switch K is closed, so that the phase difference between the two winding currents I1 and I2 is about 90 °, resulting in a rotating magnetic field, and the motor rotates; Rotation positive
The centrifugal switch is often thrown off and the starting winding is cut off.
Working principle of pole single-phase motor
After the stator enters the current, part of the magnetic field passes through the short circuit ring to generate the induced current. The current in the short circuit ring blocks the change of magnetic flux, resulting in the phase difference between the magnetic flux generated by the short circuit ring and the magnetic flux generated by the non-short circuit ring, thus forming a rotating magnetic field and making the rotor rotate.
The rotation direction of the motor in the figure above: clockwise. Because the magnetic flux without short-circuit ring is higher than that with short-circuit ring.
Conclusion: Consult the manufacturer for the size of capacitor (some motors will identify the size of capacitor on the nameplate). If you cannot consult the manufacturer, you can choose the capacitor of the motor with the same speed and power. But this is not necessarily appropriate, but there will not be too many wiring. If there is a wiring diagram, please connect according to the wiring diagram. If there is no wiring diagram, I will connect in this way and measure three pairs of resistance, and I will get three resistance values, A, B and C. A> There will be the following rules: B>C, A=B+C. Then connect the live line and the zero line to the two lines of measurement C (it is said that there is also connection to B, which I have never seen). Connect the capacitance to the two wires measuring resistance A.