Inverter compressor in the refrigerator
the Use of inverters is the most effective method of regulating the speed of rotation of the asynchronous motor with squirrel-cage rotor. In practice, it is easiest implemented method of changing the amplitude of the supply voltage. Besides, can you use it for any type of induction motors. But for a long time about the possibility of this approach and never thought: if only it worked, whatever the inverter compressor in the fridge! That's why in a known reference Bykov in refrigeration compressors 1992 year a word we have not found about the pulse generator of variable frequency. It is these today and called inverters.
Asynchronous motors and how to manage them
Almost all generators are built according to the scheme of synchronous motors. In fact, you can rotate the permanent magnet inside the coil, and will be picking up EMF. Quite correctly positioning the coils to remove the alternating current. The beauty is that in the synchronous motor shaft speed and take voltage are the same. Due to this it is possible to accurately maintain the parameters. Otherwise we would have had to straighten the flow and put the inverter in order to give power to consumers (cities and villages). What will happen if this rule to break? Will not be able to work a large part of household appliances. Stability will fall, the equipment will start to fail.
But in most everyday and work situations good induction motors, which includes a diagram of the compressor of the refrigerator. Very easy to manage. Synchronous same engines yielded the role of generators. A rotating magnetic field one way or another is used in all of these devices. The rotor of the asynchronous motor can be short-circuited or phase. In the latter case, all the windings of the rotor combined with the starting rheostat. Our conception of asynchronous motors with slip-ring motors are used not for the fact that you can change the speed, and high torque at the start. Actually, for this and enter the starting rheostat, the resistance of which after you start gradually decreasing the speed. This is a very difficult adjustment method, but it is used in trams, lifts and many other cases.
we will talk About it some other time, because the compressor refrigerators as it is not accepted to include consistently to reduce inrush current, so our today's topic is not concerned. Asynchronous motors with squirrel-cage rotor is very simple in design. Moreover, do not have slip rings, which eventually caused. This advantage leads to differences in regulation.
For phase rotors are used, the introduction of additional resistance in the circuit of the winding, zapisywanie alternating current rotating coils, as well as changes in amplitude supplied to the stator voltage. Of all of them suitable for squirrel-cage motors only last method. But there is possibility to control the speed of rotation due to the change in the frequency clocking of the supply voltage.
These household appliances and are inverters. They generate pulses of variable frequency, which is the desired impact on the speed of rotation of the rotor asynchronous motor. To understand how this works, let's briefly look at what's happening inside. The stator is supplied with alternating voltage, number of phases is not now under consideration. Thanks to the power supply inside the AC rotating magnetic field which acts on the rotor. As a result, the coils of its induced EMF, and we are created inside these magnets with the poles. Each character begins to capture the magnetic field and induction motor moves off. During this period, he consumes a significant inrush current.
the faster the rotor is spinning, the lower the frequency EMF is induced. Gradually, the system comes into balance, as if the inside of the rotating permanent magnets. Just to compare the frequency of rotation of the rotor and AC stator can't, because it will disappear EMF, and the engine will start to slow down. Then again the difference will appear.
the Induced EMF and the motor rotor newly captured field. Thus the speed will always be slightly lower than the frequency of the supply voltage. This feature is used to manipulate the speed of rotation. The inverter smoothly change the parameter and induction motor immediately obeys.
Why couldn't you put on the shaft permanent magnet that rotates with frequency fields? In synchronous motors do. Is it possible to control them by changing the frequency of the voltage? Most likely, Yes. Why synchronous motors do not use in combination with inverters? The answer is we don't know. Moreover, the literature is clear that when disconnecting the starting rheostat and shorting rings we get almost the same squirrel-cage rotor. Why is the method of changing the frequency of the supply voltage is not suitable for phase motors, remains a mystery.
But let us return to our inverters. They today are controlled compressors of refrigerators, which do not need a large starting torque. So there is every reason to believe that the inside is not applied to the rotor coils in the form of a double squirrel cage or deep grooves under plates of copper, United in the form of a drum.
Two windings just create a field, and fan blades begin to rotate, moving the freon. Soon induction motor goes on mode, after which the starting circuit is disabled by the command of the corresponding relay. As it understands that the speed has reached the set? There are several ways.
1. The induction. The starting current of a large value closes the contacts with the armature of the starting coil. Then consumption is reduced, and gradually this circuit is disconnected from the supply.
2. Thermal. The working substance of a conductor in a circuit starting coil is gradually heated and in the end, expands and breaks the electrical contact.
Left to add to this that practically every compressor for refrigerator complemented by a protective relay to prevent overheating. As a result, the device operates managed not only thermostats, and protection devices.
Inverter compressors in refrigerators
Now it is easy to understand how it works, inverter compressor in the refrigerator. In the initial moment of time the asynchronous motor starts and goes to a mode. Gradually the temperature in the cells is reduced to a predetermined, but the motor does not stop, but simply reduces the speed to minimum. As a result, the cooling rate strongly decreases but does not become zero. Gradually she begins to balance the heat loss due to imperfect insulation. If you open the refrigerator door, the warm air will rush inside, which will cause a barely noticeable increase in speed inverter compressor. But it stops very rarely, but works in a sparing mode.
that was why the company Samsung provides a full 10 year warranty on inverter compressors in refrigerators own production. And that speaks volumes. The refrigerator with linear compressor and does exclude from its construction the usual engine with a rotating rotor. The compressor is the engine! In it the piston moves linearly by changing the electromagnetic field. That is, the inverter control circuit in this case, God himself has prescribed. The higher the frequency of the power, the more often will knock and piston, driving the freon. Therefore, the cooling rate will also increase.
But a supporter of the linear compressor LG somehow not in a hurry to give 10 years warranty. What is the inverter linear compressor? This linear compressor – where the piston moves in a straight – with inverter control. Why do we think that for frequency control the future, so that high efficiency of the engine in this case. In addition, more and more it becomes evident that the method is generic. And this is not surprising. Asynchronous motors are available not only in Russia but also abroad. Work not only from 50, and 60 Hz, with different speeds… Why them and not to regulate the frequency?
How to replace refrigerator compressor
not only that, freon, you will need to fill a new, replacement refrigerator compressor still requires knowledge of such information as the type of the protective relay. Of course, it is better to put the native part, but in most cases will fit many others. We are not sure that the linear compressor can replace conventional with the crankshaft, but in the older models is usually the thermostat, and the voltage is 220 V and frequency of 50 Hz. That is, there is no modulation on the food chain. About protective relays need to worry considering that the compressor motor is not burned by the wrong regulation. Another thing is if I change the entire tandem. Then a great chance that the device will work.
by the Way, do not rush to throw out old appliances, and pay for its disposal. An old refrigerator compressor Atlas will serve us in the garage for the pump wheel. What read in the same section! Refrigerator compressor — it is worthwhile. They are becoming safer and safer, which can't be said about adsorption, which criticized the fishermen (but not able to live without them). In the near future a small chance that will come up with something new and equally effective and cheap, so the problem is to buy a compressor for the refrigerator to be disturbed by many generations of people on the planet.
On that note, we want to say goodbye and please strictly do not judge because of poor knowledge in electrical engineering. Standing textbooks still in electronic form is not translated. And in other not in use!