Is it possible to connect a single-phase motor through a frequency converter?

Question

Circuit design

Good evening.
There are two types of electric motor,
Asynchronous with a squirrel-cage rotor,
And collector (if I call it correctly, where there is a stator winding and a rotor winding)
Both for 220v.
Conclusions, respectively, 3 and 4.
The choice for a phase shift is a conder.
Am I correct in thinking that instead of two contactors, I can put a frequency converter, throw out the capacitor and put the output on T2 instead. Thus, through the chastotnik realizing the control of the direction of rotation and speed of rotation?

Answer 1

You have not listed everything: asynchronous can actually be single-phase with a capacitor phase shift or with a short circuit, and 3-phase, in which single-phase is simulated by connecting one of the phases through a capacitor. The first ones have 2 windings, the phase shift of the currents in which is 90 degrees (and this is an absolutely regular mode), the second ones have only one winding (the phase shift is done in a magnetic field due to a short-circuit coil put on a part of the core), and the third ones have 3 windings and require a phase shift of 120 degrees, but in them, by selecting a capacitor, you have to get something around 100 degrees. Such an abnormal mode leads to a shortage of power and torque, which is why at the start it is necessary to connect an additional starting capacitor to the working capacitor. But a 3-phase motor is cheap and easy to get, because this method is the most common.
Now on business. As I understand it, you want to regulate the speed of your motors with a frequency converter (what else could it be needed for?).
1. Collector - this is the same DC motor (usually with serial switching on of the stator windings), and its speed is perfectly regulated in a very wide range (up to thousands of times - say, from 15,000 to 5 rpm) by changing the supply voltage. If it is alternating current, then the simplest thyristor regulator, consisting of 4 ... 5 parts, is suitable. No chastotnik is needed for it, when changing the frequency, there may be troubles (for example, a drop in power, excessive heating).
2.Both asynchronous with a capacitor can be operated from a frequency converter, but within very narrow limits of frequency change. The reason for this is in the capacitor phase shift: the capacitor is selected for a certain frequency (and in a 3-phase also for a certain load), and as it changes, the 90-degree shift will turn into hell knows how much, and we will get a drop in power and torque, and probably too much heat.
3. Now, if there is no capacitor, then you can use the frequency converter in the usual way. But these will be only 3-phase motors in normal operation, or single-phase, very low-power ones (maximum 10 ... old gramophones).