How to connect an electric motor from 380 to 220: circuits

There are situations when equipment designed for 380 volts, you must connect to a home network at 220 V. Since the engine does not start, you need to change some details in it. This can easily be done on your own. Even though the efficiency is somewhat reduced, this approach is justified.

Three-phase and single-phase motors

To understand how to connect an electric motor from 380 to 220 volts, we find out what power is meant for 380 volts.

Three-phase motors have many advantages compared to household single-phase motors. Therefore, their use in industry is extensive. And the matter is not only in power, but also in the coefficient of efficiency. They also include starting windings and capacitors. This simplifies the mechanism design. For example, the start-up protective relay of the refrigerator keeps track of how many windings are cut. And in the three-phase engine in this element, there is no need.

This is achieved by three phases, during which the electromagnetic field rotates inside the stator.

Why 380 V?

When the field inside the stator rotates, the rotor also moves. Turnovers do not coincide with the fifty Hertzs of the network due to the fact that more windings, the number of poles is excellent, and for various reasons slippage occurs. These indicators are used to regulate the rotation of the motor shaft.

All three phases have a value of 220 V. However, the difference between any two of them at any time will be different from 220. So it turns out 380 volts. That is, the engine uses 220 V for operation, with a phase shift of one hundred and twenty degrees.

Because it is not possible to directly connect an electric motor of 380 volts to 220 volts, you have to use tricks. Condenser is considered the simplest way. When the container passes the phase, the latter changes by ninety degrees. Although it does not reach a hundred and twenty, this is enough to start and operate a three-phase engine.

How to connect an electric motor from 380 V to 220 V

To realize the task it is necessary to understand how the windings are arranged. Usually the case is protected by a casing, and under it the wiring is located. Having removed it, you need to study the contents. Often a connection diagram can be found here. In order to connect the electric motor to the network 380-220, switching in the form of a star is used. The ends of the windings are at a common point, called neutral. The phases are fed to the opposite side.

The "star" will have to change. For this, the winding of the motor must be connected to another form - in the form of a triangle, combining them at the ends with each other.

How to connect an electric motor from 380 to 220: circuits

The diagram can look like this:

• The mains voltage is applied to the third winding;
• Then the first winding voltage will pass through the capacitor with a phase shift of ninety degrees;
• The second winding will be affected by the voltage difference.

It is clear that the phase shift will be ninety and forty-five degrees. Because of this, the rotation is not uniform. In addition, the shape of the phase on the second winding will not be sinusoidal. Therefore, after connecting a three-phase electric motor to 220 volts it will be possible, it can not be realized without loss of power. Sometimes the shaft even sticks and stops spinning.

Working capacity

After a set of revolutions, the launch capacity will no longer be needed, since the resistance to movement will become insignificant. To reduce the capacity, it is shortened to a resistance through which the current no longer passes. For the correct choice of the working and starting capacitance, it must first be taken into account that the operating capacitor voltage must substantially overlap 220 volts. At least it should be 400 V. You also need to pay attention to the wires, so that the currents were intended for a single-phase network.

If the working capacity is too low, the shaft will stick, so the initial acceleration is used for it.

The working capacity also depends on the following factors:

• The more powerful the motor, the more capacitor rating will be required. If the value is 250 W, then a few tens of μF will suffice. However, if the power is higher, then the nominal value can be considered as hundreds. Condensers are better to purchase film, because the electric will have to be completed in addition (they are designed for permanent, and not alternating current, and without reworking can explode).
• The higher the motor speed, the higher the nominal value. If you take the engine at 3000 rpm and a power of 2.2 kW, then the battery will need it from 200 to 250 μF. And this is a huge value.

This capacity also depends on the load.

The final stage

It is known that an electric motor of 380 V in 220 Volts will work better if the voltages are obtained with equal values. To do this, the winding connecting to the network is not to be touched, but the potential is measured on both others.

The asynchronous motor has its own reactive resistance. It is necessary to determine the minimum at which it starts to rotate. After that, the denomination is gradually increased until all the windings are leveled.

But when the engine untwists, it can turn out that equality will be violated. This is due to a decrease in resistance. Therefore, before you connect the electric motor from 380 to 220 volts and fix it, you need to compare the values even when the unit is running.

The voltage can be above 220 V. Look to ensure a stable connection of the contacts, and there was no loss of power or overheating. The best switching is done on special terminals with fixed bolts. After connecting the electric motor from 380 to 220 volts it turned out with the necessary parameters, the casing is again put on the unit, and the wires are passed along the sides through the rubber seal.

What else can happen and how to solve problems

Often after assembly, it is found that the shaft rotates in the wrong direction to which it is necessary. The direction must be changed.

For this, the third winding is connected through a capacitor to the threaded terminal of the second stator winding.

It happens that due to prolonged work over time the engine noise appears. However, this sound is of a completely different kind in comparison with the hum when the connection is incorrect. Eventually, the motor also vibrates. Sometimes even it is necessary to rotate the rotor with force. This is usually caused by the wear of the bearings, which causes too large gaps and noise. Over time, this can lead to jamming, and later - to damage the engine parts.

It is better not to allow this, otherwise the mechanism will become unusable. It is easier to replace the bearings with new ones. Then the electric motor will last for many more years.