Most often, a single-phase 220 V network is connected to our houses, plots, garages. Therefore, equipment and all homemade products are made so that they work from this power source. In this article, we will consider how to properly connect a single-phase motor.
Asynchronous or collector: how to distinguish
In general, you can distinguish the type of engine by the plate - nameplate - on which its data and type are written. But this is only if it has not been repaired. After all, under the casing can be anything. So if you're not sure, it's best to determine the type yourself.
How collector engines are arranged
It is possible to distinguish between asynchronous and collector motors by structure. Collectors must have brushes. They are located near the collector. Another obligatory attribute of this type of engine is the presence of a copper drum divided into sections.
Such motors are produced only single-phase, they are often installed in household appliances, as they allow you to get a large number of revolutions at the start and after acceleration. They are also convenient in that they easily allow you to change the direction of rotation - you just need to change the polarity. It is also easy to organize a change in the rotation speed - by changing the amplitude of the supply voltage or its cutoff angle. That is why they are used similar engines in most household and construction equipment.
The disadvantages of collector motors are the high noise of operation on high speed. Remember a drill, a grinder, a vacuum cleaner, a washing machine, etc. The noise during their work is decent. At low speed commutator motors not so noisy (washing machine), but not all tools work in this mode.
The second unpleasant moment - the presence of brushes and constant friction leads to the need for regular Maintenance. If the current collector is not cleaned, graphite contamination (from wearable brushes) can cause adjacent sections in the drum to connect, the motor simply stops working.
Asynchronous
An asynchronous motor has a starter and a rotor, it can be one or three phase. In this article, we consider the connection of single-phase motors, because we will only talk about them.
Asynchronous motors are distinguished by a low level of noise during operation, therefore they are installed in equipment whose operation noise is critical. These are air conditioners, split systems, refrigerators.
There are two types of single phase induction motors- bifilar (with a starting winding) and capacitor. The whole difference is that in bifilar single-phase motors, the starting winding only works until the motor accelerates. After it turns off special device- centrifugal switch or start-protective relay (in refrigerators). This is necessary, because after overclocking, it only reduces efficiency.
In capacitor single-phase motors, the capacitor winding operates all the time. Two windings - main and auxiliary - are offset relative to each other by 90 °. Thanks to this, you can change the direction of rotation. The capacitor on such engines is usually attached to the case and is easy to identify by this sign.
You can more accurately determine the bifolar or capacitor motor in front of you by measuring the windings. If the resistance of the auxiliary winding is less than half (the difference can be even more significant), most likely it is a bifolar motor and this auxiliary winding is a starting one, which means that there must be a switch or a starting relay in the circuit. In capacitor motors, both windings are constantly in operation and the connection of a single-phase motor is possible through a conventional button, toggle switch, automatic machine.
Wiring diagrams for single-phase asynchronous motors
With start winding
To connect a motor with a starting winding, you will need a button, in which one of the contacts opens after switching on. These opening contacts will need to be connected to the starting winding. In stores there is such a button - this is PNVS. Her middle contact closes for the holding time, and the two extreme ones remain in the closed state.
The appearance of the PNVS button and the state of the contacts after the "start" button is released "
First, using measurements, we determine which winding is working, which is starting. Usually the output from the motor has three or four wires.
Consider the option with three wires. In this case, the two windings are already combined, that is, one of the wires is common. We take a tester, measure the resistance between all three pairs. The working one has the smallest resistance, the average value is the starting winding, and the largest is the total output (the resistance of two windings connected in series is measured).
If there are four leads, they ring in pairs. Find two pairs. The one in which the resistance is less - working, in which more - starting. After that, we connect one wire from the starting and working windings, we output a common wire. In total, three wires remain (as in the first option):
- one from the working winding - working;
- from the starting winding;
- general.
With all these 
connection of a single-phase motor
We connect all three wires to the button. It also has three contacts. Necessarily starting wire“We put on the middle contact(which closes only during start-up), the other two are extremeie (optional). We connect a power cable (from 220 V) to the extreme input contacts of the PNVS, connect the middle contact with a jumper to the working one ( note! not with common). That's the whole scheme for switching on a single-phase motor with a starting winding (bifolar) through a button.
condenser
When connecting a single-phase capacitor motor, there are options: there are three connection schemes and all with capacitors. Without them, the motor hums, but does not start (if you connect it according to the scheme described above).
The first circuit - with a capacitor in the power supply circuit of the starting winding - starts up well, but during operation, the power is given out far from the nominal, but much lower. The switching circuit with a capacitor in the working winding connection circuit has the opposite effect: not very good performance at start-up, but good performance. Accordingly, the first circuit is used in devices with a difficult start (, for example), and with a working condenser - if good performance is needed.
Circuit with two capacitors
There is a third option for connecting a single-phase motor (asynchronous) - install both capacitors. It turns out something in between the options described above. This scheme is implemented most often. It is in the picture above in the middle or in the photo below in more detail. When organizing this circuit, a button of the PNVS type is also needed, which will connect the capacitor only not at the start time, until the motor “accelerates”. Then two windings will remain connected, and the auxiliary one through the capacitor.
Connecting a single-phase motor: a circuit with two capacitors - working and starting
When implementing other circuits - with one capacitor - you will need a regular button, automatic machine or toggle switch. Everything just connects there.
Selection of capacitors
There is a rather complicated formula by which you can accurately calculate the required capacity, but it is quite possible to get by with recommendations that are derived from many experiments:
- a working capacitor is taken at the rate of 70-80 microfarads per 1 kW of engine power;
- launcher - 2-3 times more.
The operating voltage of these capacitors should be 1.5 times higher than the mains voltage, that is, for a 220 V network, we take capacities with an operating voltage of 330 V and higher. And to make the start easier, look for a special capacitor in the starting circuit. They have the words Start or Starting in the marking, but you can take the usual ones.
Changing the direction of the motor
If, after connecting, the motor works, but the shaft rotates in the wrong direction that you need, you can change this direction. This is done by changing the windings of the auxiliary winding. When the circuit was assembled, one of the wires was applied to the button, the second was connected to the wire from the working winding and the common one was brought out. This is where you need to throw the conductors.
General information
Asynchronous capacitor reversible electric motor with increased starting torque of the DAK120-2UHL4-01 series is designed to drive semi-automatic household washing machines type "Altai-electron". Works from the network alternating current voltage 220 V, frequency 50 Hz.
Symbol structure
DAC120-2UHL4-01:
DAK - asynchronous capacitor motor;
120 - power, W;
2 - conditional type of machine;
UHL4 - climatic version and placement category according to GOST
15150-69;
01 - modification.
terms of Use
Nominal values of climatic factors environment for execution UHL4 in accordance with GOST 15150-69.
Safety requirements according to GOST 12.2.007.0-75, GOST 12.2.007.1-75, GOST 16264.1-85.
Specifications
Power, W - 120 Rated rotor speed, min -1 - 2600 Rated torque, Nm - 0.44 Rated current, A - 1.2 Efficiency, %, not less than - 44 Multiplicity of initial starting torque to nominal - 0 .9 Capacitance of the working capacitor, uF - 10 Weight without pulley, kg - 4.7
Intermittent operation mode (S3) with duty cycle=60%.
Other modes of operation of the electric motor are allowed, provided that normal overheating of the windings is ensured.
Winding insulation of heat resistance class B according to GOST 8865-93.
Degree of protection IP10 according to GOST 17494-87.
Guarantee period- 2.5 years from the date of putting the engines into operation.
Design and principle of operation
General form, overall and installation dimensions engine are shown in fig. 1.
General view, overall, installation and connecting dimensions engine DAK120-2UHL4-01
Any direction of rotation of the shaft.
On fig. 2 is given circuit diagram motor connection (with reversing).
Motor wiring diagram (with reversing):
C1 - the beginning of the main winding;
C2 - end of the main winding;
B1 - the beginning of the auxiliary winding;
B2 - end of the auxiliary winding;
Cp - working capacitor 2
The package includes: engine, passport.
Single-phase motors are electrical machines of small power. In the magnetic circuit of single-phase motors there is a two-phase winding, consisting of the main and starting windings.
Two windings are needed in order to cause the rotation of the rotor of a single-phase motor. The most common motors of this type can be divided into two groups: single-phase motors with a starting winding and motors with a run capacitor.
For motors of the first type, the starting winding is switched on through the capacitor only at the time of starting, and after the motor has developed a normal rotation speed, it is disconnected from the network. The motor continues to operate with one working winding. The size of the capacitor is usually indicated on the nameplate of the motor and depends on its design.
For single-phase asynchronous AC motors with a running capacitor, the auxiliary winding is connected permanently through the capacitor. The value of the working capacitance of the capacitor is determined by the design of the engine.
That is, if the auxiliary winding of a single-phase motor is starting, it will only be connected during the start-up, and if the auxiliary winding is capacitor, then it will be connected through a capacitor that remains on during engine operation.
It is necessary to know the device of the starting and working windings of a single-phase motor. The starting and working windings of single-phase motors differ both in the cross section of the wire and in the number of turns. The working winding of a single-phase motor always has a larger wire section, and therefore its resistance will be less.
Look at the photo you can clearly see that the cross section of the wires is different. A winding with a smaller cross section is the starting one. You can measure the resistance of the windings with pointer and digital testers, as well as an ohmmeter. A winding with less resistance is a working one.
Rice. 1. Working and starting windings of a single-phase motor
Here are some examples that you may come across:
If the engine has 4 outputs, then having found the ends of the windings and after measuring, you can now easily figure out these four wires, the resistance is less - working, the resistance is more - starting. Everything is connected simply, 220v is supplied to thick wires. And one tip of the starting winding, on one of the workers. On which of them there is no difference, the direction of rotation does not depend on it. It also depends on how you insert the plug into the socket. Rotation will change from connecting the starting winding, namely, changing the ends of the starting winding.
Next example. This is when the motor has 3 outputs. Here the measurements will look like this, for example - 10 ohms, 25 ohms, 15 ohms. After several measurements, find the tip from which the reading, with the other two, will be 15 ohms and 10 ohms. This will be one of the network wires. The tip, which shows 10 ohms, is also network and the third 15 ohm will be the starting one, which is connected to the second network through a capacitor. In this example, the direction of rotation, you will not change what it is and will be. Here, in order to change the rotation, it will be necessary to get to the winding circuit.
Another example, when measurements can show 10 ohms, 10 ohms, 20 ohms. This is also one of the varieties of windings. Such, went on some models of washing machines, and not only. In these motors, the working and starting windings are the same (according to the design of three-phase windings). There is no difference here which one you will have working and which starting winding. , is also carried out through a capacitor.
Edited by A. Povny
Hello, dear readers and guests of the Electrician's Notes website.
I am often asked about how you can distinguish between a working winding and a starting winding in single-phase motors when there is no marking on the wires.
Every time you have to explain in detail what and how. And today I decided to write a whole article about it.
As an example, I'll take single-phase electric motor KD-25-U4, 220 (V), 1350 (rpm):
- KD - capacitor motor
- 25 - power 25 (W)
- U4 - climatic version
Here is his appearance.
As you can see, there is no marking (color and digital) on the wires. On the engine tag you can see what marking the wires should have:
- working (С1-С2) - red wires
- starting (B1-B2) - blue wires
First of all, I will show you how to determine the working and starting windings of a single-phase motor, and then I will assemble a circuit for turning it on. But this will be the next article. Before you start reading this article, I recommend that you read:.
So let's get started.
1. Cross section of wires
Visually look at the cross section of the conductors. A pair of wires with a larger cross section belong to the working winding. And vice versa. Wires with a smaller cross section belong to the starting wire.
Then we take the probes of the multimeter and measure the resistance between any two wires.
If there is no reading on the display, then you need to take another wire and measure again. Now the measured resistance value is 300 (Ω).
We found the conclusions of one winding. Now we connect the multimeter probes to the remaining pair of wires and measure the second winding. It turned out 129 (Ohm).
We conclude: the first winding is starting, the second is working.
In order not to get confused in the wires when connecting the engine in the future, we will prepare tags (“cambric”) for marking. Usually, as tags, I use either a PVC insulating tube or a silicone tube (Silicone Rubber) of the diameter I need. In this example, I used a 3 (mm) silicone tube.
According to the new GOSTs, the windings of a single-phase motor are designated as follows:
- (U1-U2) - working
- (Z1-Z2) - launcher
The KD-25-U4 engine, taken as an example, digital marking done in the old way:
- (C1-C2) - working
- (B1-B2) - launcher
So that there are no inconsistencies between the wire marking and the circuit shown on the engine tag, I left the old marking.
I wear wire tags. Here's what happened.
For reference: Many are mistaken when they say that the rotation of the engine can be changed by rearranging the mains plug (changing the poles of the supply voltage). It is not right!!! To change the direction of rotation, you need to swap the ends of the starting or working windings. The only way!!!
We considered the case when 4 wires are connected to the terminal block of a single-phase motor. And it also happens that only 3 wires are output to the terminal block.
In this case, the working and starting windings are connected not in the terminal block of the electric motor, but inside its housing.
How to be in that case?
We do everything in the same way. We measure the resistance between each wire. Mentally label them as 1, 2 and 3.
Here's what I got:
- (1-2) - 301 (Ohm)
- (1-3) - 431 (Ohm)
- (2-3) - 129 (Ohm)
From this we draw the following conclusion:
- (1-2) - starting winding
- (2-3) - working winding
- (1-3) - starting and working windings are connected in series (301 + 129 = 431 ohms)
For reference: with such a connection of the windings, the reverse of a single-phase motor is also possible. If you really want to, you can open the motor housing, find the junction of the starting and working windings, disconnect this connection and put 4 wires into the terminal block, as in the first case. But if your single-phase motor is capacitor, as in my case with KD-25, then it.
P.S. That's all. If you have questions about the material of the article, then ask them in the comments. Thank you for your attention.
