For your attention, already 70 in a row a question with such a title was asked by the reader Alexander. If you have your own answer to the question, then write it in the comments below. I and other readers of my channel will be happy to read it.
The text of the question itself:
Good day. I got an asynchronous motor with a short-circuit rotor from a washing machine. The problem is as follows: three terminals, two windings have the same resistance of 43 ohms, the total resistance of the two windings is 86 ohms. Do the same resistances indicate a malfunction in the motor? If not, then how to divide the windings into working and starting, preferably without opening the motor? W1D30VC006 daewoo engine. Thanks in advance for your help.
I reviewed the issue and advised Alexander within the framework of my knowledge and qualifications as follows:
The Daewoo W1D30VC006 asynchronous electric motor you are using is two-phase. This means that both windings in it are equivalent, as your measurements showed - the resistance of one winding is equal to the resistance of the other. Such a ratio of parameters is necessary to create two equal in value magnetic fields, which are displaced when powered from household electrical circuits due to a connected capacitor. On the nameplate of the electrical machine, there should be a schematic mark showing the connection method.
Therefore, in this case, there is no way to separate the working and starting windings, your electric machine is designed to work with both windings at once. Therefore, it is possible to separate one winding from another by disassembling the case, but such a step will significantly affect the efficiency of the electric motor.
Anticipating various comments (indignant and satisfied) from readers, I will give several TYPICAL from readers who entered into a discussion with me (on my website) on this issue and my comments to them.
1. Comment from Vitaly:
You did not describe correctly!!! According to the author, this engine is reversible. The two coils are the same. In your figure, you need to take the middle wire as a common one and connect the capacitor to the upper and lower terminals. If voltage is applied to the common and upper terminals, the motor rotates in one direction. If you apply to the common and lower - to the other. The wire, relative to which the resistance of the coils is equally considered as common. And no separation is needed.
My answer:
No, you are not carefully reading the question of the author of the question, we are talking about an electric motor from a washing machine. What are you going to reverse in it? Do you want your laundry to rotate in one direction or the other? Moreover, with modern methods of reversing electrical machines, the method you proposed leaves half the winding unused.
The washing machine is not a case where the electric motor starts up for a short time and such unreasonable costs can be neglected. I recommend that you read what types of electric motors are used in washing machines, in this case it is a two-phase asynchronous electric machine.
On the other hand, if we consider the option you proposed: a capacitor between the lower and upper, and apply the voltage to the middle terminal and any of the connected capacitors, then from which, in your opinion, the AC motor will begin to rotate current? Your vector diagram will be tuned only from one phase, the capacitor will simply hang in the air, the motor shaft will not move from its place.
Moreover, the drawing of the motor connection is taken from the passport photo of the original electrical machine. Therefore, the connection method was not developed from scratch, but was proposed by the manufacturer.
2. Comment from Andrey:
What's the point in separating the windings? The motor is two-winding, and if there are three terminals, the starting one can be any of these windings. And this scheme provides a reverse with a bang.
My answer:
No one proposes to separate the windings, the text of the question clearly states the condition - the resistance of the windings is the same, which means that both workers are constantly energized. In the example under consideration, a two-phase electric motor is shown, in one of the phases of which there is a phase voltage, and in the other, the same phase is displaced by connecting a capacitor. Thanks to this difference, the rotation of the rotor of the electric machine occurs.
If we consider an electric motor with a starting winding, then it will have a significant difference from the working one in terms of ohmic resistance. And this is no longer a two-phase, but a single-phase electric motor. For a washing machine, a single-phase asynchronous electric motor is not used due to the technical parameters of the household appliance.
I already wrote about the reverse in previous replies, but it is possible to reverse the engine from the washing machine and it is technically implemented, but in completely different devices. In practice, you don't need to use reverse in a washing machine, the engine simply rotates the drum in one direction, changing the number of revolutions, that's all!