If we turn our eyes on all kinds of technology used in our world, we find that it is often used asynchronous type electric motors. In order for such an electric motor to rotate frequently, it is necessary to have a mandatory rotating magnetic field. Similar units differ:
- low noise
- good performance
- as well as ease of use
To create such a magnetic field, three phase network required. In this case, it is enough to arrange 3 windings in the stator of the electric motor, which will be placed at an angle one hundred and twenty degrees relative to each other, then connect the necessary and appropriate to them voltage. It is then that the circular rotating field will be able to rotate the stator.
In everyday life, devices are often used that have only a single-phase electrical network. The most common single-phase asynchronous motors are used for such devices.
When we put a winding in the stator of an electric motor, the magnetic field in it can be formed only specifically when an alternating sinusoidal current flows. This field, however, to force the rotor to rotate, unfortunately, can not. To start the engine, you need to perform two actions. First, place an additional winding on the stator.
1 Starting and working types of connection schemes
- 1.1 Using start capacitor
- 1.2 The advantages of the scheme with the working type of the element
- 2 A few general operating tips
Starting and working types of connection schemes
When you perform the required actions, a circular magnetic field will arise in the electric motor, respectively, and the corresponding currents will appear in the rotor. The interaction of current and stator field can cause the rotor to rotate. There are several ways to connect capacitors to an electric motor.
Depending on the method, different types of schemes are distinguished. In these circuits, one can use, firstly, a starting capacitor, secondly, a working capacitor, as well as a starting capacitor and a working capacitor at the same time. In this case, the most common method is to connect with a starting capacitor.
Using start capacitor
When we start the engine, then the capacitor and start winding are turned on. This is due to the property that the unit continues to rotate even when the additional winding is disconnected. For such a launch most often use a relay and a button.
Due to the fact that the start-up of a single-phase electric motor with a capacitor occurs fairly quickly, the additional winding often takes a very short time. Due to this, in order to save it, it is possible to perform it from a wire with a relatively smaller cross section than the main winding itself. To prevent and prevent overheating of additional winding, thermostats or a centrifugal switch are almost always added to the circuit. Thanks to these devices, when the motor is set to a certain speed or when strong heating is reached, it becomes possible to control the shutdown.
A circuit that uses a starting capacitor has pretty good starting characteristics of the electric motor, but at the same time the performance is somewhat worse.
The advantages of the scheme with the working type of the element
You can get much better performance if you use a circuit with a working capacitor. After starting the electric motor, the capacitor in this circuit does not turn off. Proper selection of a capacitor for a single-phase electric motor can provide great benefits. The main one is field distortion compensation and increase the efficiency of the unit. However, as was to be expected, the starting characteristics deteriorate in such a scheme.
It should also be borne in mind that when choosing the value of the capacitance of the desired capacitor for the electric motor is based on a certain load current. If the current changes relative to the calculated value, then the field will move from a circular to elliptical form, and as a result, the characteristics of the unit will deteriorate. To ensure high good performance, in principle, it is necessary only when the load of the motor changes change capacitance value. However, this can make the inclusion scheme too complicated.
The most compromise solution to this problem is the choice of a circuit with start and working capacitors at the same time. In such a scheme, the starting and operating characteristics will be average relative to the previously reviewed schemes. In general, if an important large starting torque is required when connecting a single-phase motor, then in this case the circuit is chosen specifically with a starting element. If there is no such need, then, accordingly, the work item is used.
A few general operating tips
When choosing a scheme, the user always has the opportunity to choose the scheme that specifically suits him. However, usually all the conclusions of the desired windings, the conclusions of the capacitor for the electric motor are put into a terminal box.
If you need to modernize the system, and maybe even do the required calculation of the capacitor for your single-phase motor, then you can give you advice. We must proceed from the fact that for every kilowatt of power your unit requires guaranteed specific capacity 0.7 - 0.8 microfarad relative to the working type or, respectively, two and a half times the large capacity relative to the type of starting.
When checking the technical condition of the engine, you can often notice that after quite a long time, there was an unwanted noise and unpleasant vibration. The rotor is difficult to verify. The reason may be the poor condition of the bearing. Treadmills were covered with terrible rust, scratches, dents. Some balls and separator are damaged. In all these cases, you need to consider in detail and eliminate your existing faults. However, minor damage is often sufficient:
- carefully and thoroughly wash the bearings with gasoline;
- then lubricate them;
- to clean the body of your engine from dust and dirt.