Circular saw
To collect a circular saw yourself is not only to get a functional device for cutting wood, but also to save significant means. The most important part of such a device is the electric motor. The article gives the basics of selecting an electric motor, its connection and installation for a home.made circular.
The voltage of 220 V is universal in household electrical networks, but the devices for 380 V are considered more stable and powerful. In principle, both parameters are able to satisfy the conditions for connecting an asynchronous engine for a circular saw.
It is better to use a voltage of 380V, t.to. It allows you to use a more powerful engine, moreover, with a large torque.
If the house does not have a voltage of 380V, then you will have to use 220V.
There are situations when there is an engine for 380V, and in the house a voltage of 220V in the house. How to connect such an engine?
How to connect 380 V to a voltage of 220 V
All possible connection schemes for converting 220 V B 380 V are indicated on the electric motor nameplate. Therefore, first we look at him and first of all are guided by what is written there.
In practice, when connecting an ordinary asynchronous engine, 2 methods are used:
- frequency converter. Its purpose is converted 1 phase at a voltage of 220 V in 3 phases 380 V with exactly the same voltage parameter. Frequency frequencies are expensive, therefore, they are rarely used to transform at home;
- With the help of a capacitor. You need an alternating current device. But the capacitor should be connected to one of the engine windings. in this case, the phase will occur and the torque will occur due to the formation of the EMF in the magnetic field.
You can not use capacitors for direct current in a network with alternating current, since during operation the device can overheat and explode.
After watching the video, you can see two practical ways to connect an electric motor for 380V to an AC household network.
What characteristics do you need to pay attention to: power, revolutions
The main characteristic of the electric motor is power. The following power ranges are selected for circular saws:
- up to 800 watts. low.power saws for sawing small wooden blanks;
- from 800 watts to 1200 W. saws with engines in such a powerful range are mounted in small carpentry and furniture workshops with fluid production;
- over 1200 W are very powerful circular circus, which provide uninterrupted production in conditions of large woodworking workshops.
If you do wrong to choose power and load low.power engines with fluid work, then they will soon become unusable.
The speed of rotation of the sawing disc of the circular disk is directly dependent on the number of revolutions of the engine shaft. As a rule, electric motors are selected in the range from 3,000 to 6000 rpm. At the same time, a value of 5000 rpm is considered the best value, which allows:
- easy to cut solid rocks.
- produce a more even fishing line for a cutting trimmer when using disks of different thicknesses.
- Avoid jamming the saw disk in wood.
It should be noted that the temperature of the working surface with prolonged contact with the saw depends on the speed of rotation. The higher the speed. the stronger the heating.
A powerful, resourceful tool is a great danger, so it requires professional use from the owner.
How to connect a single.phase engine
Most often, a single.phase network of 220 V was brought to our homes, plots, garages. Therefore, equipment and all homemade ones make them so that they work from this power source. In this article, we will consider how to make a single.phase engine connection correctly.
In general, you can distinguish the type of engine by a plate. a nameplate. on which its data and type are written. But this is only if it was not repaired. After all, under the casing can be anything. So if you are not sure, it is better to determine the type yourself.
This is how the new single.phase condenser engine looks like
How collector engines are arranged
You can distinguish asynchronous and collector engines by structure. Collector has brushes. They are located near the collector. Another mandatory attribute of the engine of this type is the presence of a copper drum divided into the section.
Such engines 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 can easily change the direction of rotation. you only need to change the polarity. It is also easy to organize a change in the speed of rotation. a change in the amplitude of the supply voltage or the angle of its cutting off. Therefore, such engines are used in most of the household and construction equipment.
Disadvantages of collector engines. high noise at large speeds. Remember the drill, corner grinder, vacuum cleaner, washing machine, etc.D. Noise when they work is a decent. At low speeds, collector engines are 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 toxicer is not cleaned, pollution by graphite (from erasing brushes) can lead to the neighboring sections in the drum will connect, the motor will simply stop working.
Asynchronous
The asynchronous engine has a stator and a rotor, it can be one and three.phase. In this article we consider the connection of single.phase engines, therefore we will only talk about them.
Asynchronous engines are characterized by a low level of noise during operation, therefore they are installed in a technique whose noise is critical. These are air conditioners, split systems, refrigerators.
There are two types of single.phase asynchronous engines. bifiral (with launch winding) and condenser. The whole difference is that in bifile single.phase engines, the launch winding works only until the engine is accelerated. After it is turned off by a special device. a centrifugal switch or a start.up relay (in refrigerators). This is necessary, because after overclocking it only reduces the efficiency.
In condenser single.phase engines, the condenser winding works all the time. Two windings. the main and auxiliary. are shifted 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 on this basis it is easy to identify.
accurately determine the bifier or condenser engine in front of you, you can by measuring the resistance of the windings. If the resistance of the auxiliary winding is more twice (the difference can be even more significant), most likely, it is a bifier engine and this auxiliary winding is launching, which means that the circuit must contain a switch or a starting relay. In condenser engines, both windings are constantly in operation and connecting a single.phase engine is possible through a regular button, toggle switch, automatic machine.
Connection schemes for single.phase asynchronous engines
With a launch winding
To connect the engine with the start winding, you need a button in which one of the contacts after turning on is opened. These opening contacts will need to be connected to the launch winding. There is such a button in stores. this is PNVS. Her average contact closes at the time of retention, and two extreme ones remain in a closed state.
The appearance of the PNVS button and the state of contacts after the “Start” button is released “
First, using measurements, we determine what kind of working winding, which is the starting. Typically, the output from the motor has three or four wires.
Consider the option with three wires. In this case, two windings are already united, that is, one of the wires is the general. We take the tester, measure the resistance between all three pairs. The worker has the smaller resistance, the average value is the starting winding, and the greatest is the general output (the resistance of two sequentially turned on the windings is measured).
If there are four conclusions, they call in pairs. Find two pairs. The one in which the resistance is less. the working one, in which there is more. starting. After that, connect one wire from the starting and working winding, display the general wire. Total three wires remain (as in the first version):
With these three wires and work further. we use to connect a single.phase engine.
We connect all three wires to the button. It also has three contacts. Be sure to “put the starting wire“ put on average contact (which is closed only for the time of starting), the other two. to the extreme (arbitrarily). We connect the power cable (from 220 V) to the extreme input contacts of the PNVS, connect the average contact with a jumper with the worker (pay attention! not with the general). That’s the whole circuit of turning on a single.phase engine with a starting winding (bifILAR) through the button.
Condenser
When connecting a single.phase condenser engine, there are options: there are three connection schemes and all with capacitors. Without them, the motor is buzzing, but does not start (if you connect it according to the scheme described above).
Single condenser engine connection diagrams
The first scheme. with a capacitor in the supply circuit of the starting winding. are well launched, but during operation the power is far from nominal, but much lower. The switching circuit with the capacitor in the connection circuit of the working winding gives the opposite effect: not very good indicators when starting, but good working characteristics. Accordingly, the first scheme is used in devices with heavy starting (concrete mixers, for example), and with a working condenser. if good working characteristics are needed.
Two condenser circuit
There is another option for connecting a single.phase engine (asynchronous). install both capacitors. It turns out something between the options described above. This scheme is most often implemented. It is in the figure above in the middle or in the photo below in more detail. When organizing this scheme, you also need a button like PNVS, which will connect the capacitor only not the start time while the motor “accelerates”. Then two windings will remain connected, and the auxiliary through the capacitor.
Connecting a single.phase engine: a scheme with two capacitors. working and starting
When implementing other schemes. with one capacitor. you will need a regular button, machine or toggle switch. Everything is connected there simply.
Selection of capacitors
There is a rather complicated formula by which you can calculate the required container for sure, but it is quite possible to do with recommendations that are bred on the basis of many experiments:
The operating voltage of these capacitors should be 1.5 times higher than the network voltage, that is, for the 220 volts, we take capacities with an operating voltage of 330 V and above. And to make the start passes easier, look for a special capacitor for the starting circuit. They have the words of Start or Starting in the labeling, but you can take the usual.
Changing the direction of movement of the motor
If after connecting the motor works, but the shaft is spinning in the direction that you need, you can change this direction. This is done by changing the windings of the auxiliary winding. When the scheme was assembled, one of the wires was fed to the button, the second was connected to the wire from the working winding and brought out the general. Here it is necessary to throw the guides.
Assembly of a fugitive machine
The assembly of a fuganka is carried out in several stages. First you should assemble the bodybirth case, into which an electric rhinom. The case has the appearance of an ordinary wooden box without a bottom. It is covered with a thick sheet of plywood on top of it, in which a hole for installing a shirt erupts. The plywood will bear the weight of the tool, and to work with the material it must be covered with two more sheets, the thickness of which will differ by 1-2 mm. They are installed on the right and left sides of the rubbish. At the same time, thin plywood plays the role of the serving table, and the fat plywood. the receiving.
The principle of interaction between the serf and receiving tables is extremely simple: lumber, moving one half of the workbench, reaches a rubbish, while a layer of chips with a thickness of 1-2 mm is removed from it. Already processed wood at one end falls on the host part of the table, where it takes a stable position, thereby giving the possibility of the rest of the board to go over the shirt. In addition to the function of support, this ensures a decrease in vibration and makes it possible to ensure reliable emphasis during operation.
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Collecting a jacket with a shaft is a little more difficult, but if there is experience, it will also not take much time. Such a machine consists of similar details. a body that feeds and receives a table for collecting chips. It will not be superfluous in such a model of a home.made device that will reduce the speed of rotation of the shaft to pass the problem areas. significant irregularities, knots, and t.P. Of great importance is the calculation and accurate adjustment of all elements of the case to each other, ensuring reliable engine mounting and ideal leveling of desktop.
Circular saw device
The device of the circular saw, like most stationary machines, consists of such main parts:
- Bed or base;
- Engine. most often it is an asynchronous electric motor;
- Belt gear. pulleys and gear belt;
- Working shaft of the circular saw;
- Desktop;
- Security devices;
- Electrical equipment.
The entire layout of the device is based on a massive bed or base. It can be a whole part cast from aluminum of cast iron, or to have the form of a frame. a case collected from trimming pipes or corners. A homemade machine is preferable to make profile pipes out of scraps, for example, you can use square profile pipes 25×25 mm or a rectangular profile 20×40 or 25×50.
A spindle for fastening a disk circular saw is used in the form of a thread on the shaft. Pile clamp in this case is made using a nut. The spindle knot can be made in a different way, since the manual circular saw-drill the hole in the shaft, cut the inner thread and clamp the disk with a bolt. But as practice shows the first option is better. the circular saw is more reliable, and the thickness of the canvas can be selected different.
When using belt transmission, the electric motor and working shaft are connected by a wedge belt. Rotational movement from the motor shaft through the pulley is transmitted to the pulley of the working shaft. It is recommended to construct a circular sawing machine according to this scheme, this will increase the motor resource and exclude the possibility of jamming. If the circular disc is jammed and it stops, and the belt will simply stretch, and the engine will continue to work.
The desktop is necessary so that the workpiece during operation is in one plane. The table of the circular is made as wide as possible, so that you can calmly rely on the detail about its plane.
In order for the woodworking circular machine to be safe, devices are necessarily installed that ensure the safety of work. It can be a protective casing, a pusher for working with small details, parallel emphasis.
Read how to cut a laminate with an electrician without chips
One of the options to assemble a simple budget machine for homework is the option of remaking a manual circular to a stationary one, adding a stanch and a wide working surface to the actually finished device.
Countertop
A sheet of metal 2 mm thick will be used as a desktop tabletop in the circular. This is enough for the workpiece to move freely along the desktop.
Holes are made in the metal for planting screws with a secret head. In addition to metal, a wood-boom plate can be used as a table, and make it from plywood. The circular desktop is recommended to make it so that you can set the emphasis on it.
Homemade options
There are many schemes for the modernization of power tools using SCP. Among all varieties, devices on Simistors are widely used. Simistor is a semiconductor element that allows you to smoothly adjust the power parameters. There are simple and complex schemes that differ among themselves options for execution, as well as the supported power, connected power tools. The constructive design is internal, allowing you to integrate inside the body, and external, made in the form of a separate module, which acts as a speed limiter and starting current during direct starting angular grind.
The simplest scheme
UPP with the regulation of revolutions on the thyristor KU 202 has been widely used due to a very simple execution scheme (Scheme 1). Its connection does not require special skills. Radio elements for him to get it very simple. This model of the regulator is made of a diode bridge, a variable resistor (acts as a regulator U) and the tiristor setup circuit (feed U to a 6.3.volt number control exit) of a domestic manufacturer.
Scheme 1. The electrical circuit of the internal unit with speed adjustment and a smooth start (electrical circuit circuit)
Due to the size and number of parts, the regulator of this type can be built into the power tool case. In addition, the handle of a variable resistor should be removed and the revolution regulator itself can be finalized by integrating the button in front of the diode bridge.
The basic principle of operation is to adjust the revolutions of the instrument electric motor due to restriction of power in manual mode. This circuit allows the use of power tools with a capacity of up to 1.5 kW. To increase this indicator, it is necessary to replace the thyristor with a more powerful one (information about this can be found on the Internet or a directory). In addition, it is necessary to take into account the fact that the thyristor control scheme will differ from the original. KU 202 is an excellent thyristor, but its significant drawback is to set it up (a selection of parts for the control scheme). To make a smooth start in automatic mode, scheme 2 (SCP on the microcircuit) is used).
Smooth launch on the microcircuit
The best option for the manufacture of SCP is the SCP scheme on one simistor and microcircuit, which controls the smooth opening of the transition P-N type. The device from the 220 V network is powered and it is easy to assemble it yourself. A very simple and universal scheme of smooth starting the electric motor also allows you to adjust the speed (Scheme 2). Simistor can be replaced with similar or with characteristics exceeding the initial ones, according to the reference book of the semiconductor.type radio elements.
Scheme 2. Scheme of smooth launch of power tools
The device is implemented on the basis of the KR118PM1 chip and the Simistor. Thanks to the universality of the device, it can be used for any tool. It does not require tuning and is installed in the rupture of the power cable.
When starting the electric motor, the UD on KR118PM1 and the smooth growth of the capacitor C2 occur. The thyristor opens gradually with a delay depending on the capacity of the control capacitor C2. With a capacity of C2 = 47 μF, a delay occurs when it is launched about 2 seconds. It depends directly in proportion to the capacitor capacity (with a larger capacity, the launch time increases). When disconnected, the angular grinder capacitor C2 is discharged using the resistor R2, the resistance of which is 68 K, and the discharge time is about 4 seconds.
To regulate revolutions, you need to replace R1 with a variable resistor. When the parameter of the variable resistor changes, the power of the electric motor occurs. R2 changes the value of the current flowing through the input of the systemist. The simistor needs cooling and, therefore, a fan can be built into the module case.
The main function of capacitors C1 and C3 is the protection and management of the microcircuit. The Simistor should be selected, guided by the following characteristics: Direct U should be 400.500 V and direct current should be at least 25 A. With such values of radio elements, it is possible to connect a tool with a capacity of 2 kW to 5 kW to the UPP.
Thus, to launch electric motors of various tools, it is necessary to use the UPP of the factory manufacturing or homemade. SCP are used to increase the life of the tool. When the engine is launched, there is a sharp increase in the consumption current by 7 times. Because of this, it is possible to burn stator windings and wear of the mechanical part. SCP allow significantly reducing the starting current. In the manufacture of SCP, you need to comply with the safety rules when working with electricity.
When the electric engine is launched, there is a starting moment that seals the voltage due to the occurrence of starting currents. They are 9 times higher than working currents. This does not affect the stable operation of electrical appliances, reduces the life of the engine. All because the engine starts begins to drag out and its windings are overheated. Experts advise adding devices to the engine that can start it with smooth. Homemade also learned to make devices for smooth starting an electric engine with their own hands.
Overloading when starting electric motors
The start of the starting is the beginning of the movement of the engine shaft connected to the gear rates. At this moment, the rotor movement is quite unstable. Transmanding mechanisms make the shaft rotate under a large load. Such instability will necessarily lead to shock loads, and this poorly affects the gear ratings. This affects the veneer of the engine shaft and on the gearbox.
The smooth starting device smooths out the load when starting. The movement of the shaft begins with very small revolutions, and the speed gradually increases. This means that there are no strokes and loads on the transmission mechanisms. This is the principle of operation of the smooth launch of an electric motor.
It is worth noting that the devices of the smooth launch that are made in factories are universal devices. They can be used for various tasks. First of all, this is a smooth launch of the electric motor, its gradual inhibition, protection of the electric network and devices from dangerous overloads. Anyone can find a suitable product for certain tasks. Such devices have a great drawback, which consists in the high cost. But you can make a device for a smooth launch of an electric motor with your own hands, spending a minimum amount of money and time on this.
Appointment
The corner grinder was originally created to grind surfaces. But due to significant modernization of the design, it quickly began to perform such useful functions as cutting and processing of any building materials, including cement, concrete, brick, tile, slate and all types of metals.
According to the methods of performing work, an angular grinder, like the entire power tool, is created for operation in one of two modes:
- constant work in construction conditions with overcoming maximum loads during a full work shift. professional models;
- For single use with the organization of breaks in nominal loads. household tools.
This is one of the important differences must be taken into account when buying. It affects the cost of corner grinding.
Professional models
For the tool to work for a long time in extreme conditions and at the same time convenient manufacturers use all kinds of technical tricks. For example, slightly reduce the dimensions of the engine and its weight for windings of the stator and rotor allows the isolated copper wire not the usual round section, but in the shape of a square.
Even the composition of the plastic for the case is selected such a design that when it is heated up to 140 o, it does not transmit the high temperature to the operator’s hands and at the same time does not lose its strength.
- vibration protection inserts on handles that prevent the development of occupational diseases;
- Quick.sounding SDS nuts that allow you to install the working organs without using a special key;
- rotary rear handle;
- the rotation function of the gearbox or the ability to rearrange the front handle in one of the three provisions;
- a special design of bearings, ensuring the balancing of the working body;
- long power cord with a protective layer of strong insulation;
- the possibility of regulating the number of revolutions of the working circle and a number of other useful functions.
Household tool
Corner grinder of this class is inferior in their characteristics to a professional tool. However, they are produced according to strict technical standards, meet security standards, allow you to perform work in compliance with breaks.
Features and service life
In manual power tools, such as: angular grinder (angular grinder), circular saw, electric screwdriver, drill. collector engines with sequential excitement are used. They can work on constant and on alternating current.
In most cases, a regular power grid 230 in 50 Hz is used to write them down in most cases. Previously, a network of 380 in a professional tool was used. Now, with the growth of consumer power in single.phase networks (offices and residential sector), professional power tools for 220 in.
Collector engines have a large torque and starting moments, compact, are easily made for increased voltage. The torque here is a decisive. With a low mass of the machine, it is just suitable for manual power tools. But such electric motors have disadvantages and weaknesses. One of these weaknesses is the brush knot.
Brushes from pressed graphite with fillers rub on the copper plates of the collector and are subjected to mechanical wear and electricity. This leads to an increase in sparking and increases the fire and explosion hazard of the power tool. Mineral dust getting inward accelerates wear. Although the fans provided for by the design blow air out, dust and cement can easily get inside. During downtime, if the tool was unsuccessfully laid, dust easily gets inside. In practice, this is a constant phenomenon.
Brushes of an electric motor from pressed graphite
Another drawback of the power tool is frequent breakdowns of the gearbox. This happens just due to a large starting moment. The advantage turns into a disadvantage. With a breakdown of the gearbox, you have to change the tool, they usually are not subject to repair. Unfortunately, industry, in an effort to reduce the cost of products, does this due to the quality. If you want to use a good power tool. pay a lot of money.
Mobile parts
Having finished connecting the engine and making sure that it is normally increasing and dumping turns, it is allowed to move directly to the device of the circular.
We will figure out what mobile nodes that the main load falls on, we need:
The drive of the drive should be carried out in this way. The engine transfers rotation to the shaft on which a small pulley is pressed. The latter puts on a belt that sends the momentum to the second pulley. At first glance, everything seems simple, but when the installation of the circular is carried out, there are many difficulties that should be solved.
A small pulley is mandatory. It arranges three to four cross.looking furrows so that the belt has the opportunity for a good hook.
The belt can not be used from the old washing machine, just take an analogue from another unit. The main thing is that it differs with strength and has cloves.
A few larger diameter disks are welded to the edge of a large pulley to get a ledge that does not allow the belt to slip in the process of working. It is not necessary to sharpen the backbone on this pulley, the clutch with the belt will be quite enough.
The shaft holding the circular’s saw, fasteners in the form of washer and nuts should differ in reliability so that at maximum speed the saw is not subject to deformation and does not slip away, injuring workers. It is recommended to use the shaft and fasteners from the circular manufactured in the factory.
The procedure for the installation of circular is described for a saw with a three hundredth disk. Many will say that the engine from the lubricants will not pull such a saw and will stop. But here you should remember several rules:
- On the circular, you need to be able to work correctly;
- Dawn of domestic purposes, designed to work with small volumes of materials;
- The successful work of such a saw is confirmed by numerous reviews.
Simply put, the saw should not be overloaded excessively, and at idle it is better not to work for it.
Which motor to choose?
The first criterion for choosing a motor for circular saw is power. It is recommended to choose among engines equipped with a wedge.shaped belt.
This will simplify the process of turning to the saw disc.
To launch a disc of 350 mm, 1 kW of energy will be required. If you use the disc 170 mm, then approximately 500 watts are needed. Therefore, to build a circular, the engine of the old washing machine is used.
In the circular, it is important to be able to control the number of revolutions of the motor, otherwise the saw will simply break the material. In washing machines for managing the number of revolutions is responsible for the tacracker who controls the control module. However, the device does not connect to the circular, so you have to use the voltage regulator.
Design and principle of operation
And one more very important point. Calculation of the nominal capacitors Conditions: joint venture. launch, cf. worker. There are several options, but most often electricians are installed in the condenser circuit.
In some designs, a centrifugal switch is placed, which, when a certain speed of rotation is reached, opens the contacts.
Further, knowing the operating voltage and the required container select the capacitors by parameters: types and desired amount. In addition, phase shift can be obtained by using the starting phase with a large resistance value and a lower inductance.
To begin with, there are two standard circuits for connecting an electric motor to a three.phase network: a star and a triangle. For this, active resistors, inductance coils and capacitors can be used.
And one tip of the starting winding, on one of the workers. Here, each winding is used on its operating voltage, hence the power.
Determining the wires of wires related to one winding The second task is to determine the beginning and end of the windings is somewhat more complicated and requires the presence of a battery and a stir voltmeter. However, in this case, a decrease in the speed of rotation will be reduced.
The phase is supplied to one terminal, on the other zero, the inclusion of the condenser group is made to the third. They even indicate on the tags that it is possible to connect to both a three.phase network and a single.phase. Connector connection. How to connect the capacitor to the electric motor. Scheme.
Connecting two capacitors for a three.phase engine
To start the engine in a loaded state, the addition of a starting capacitor is required. He carries out work in the first few seconds during launch and stops working when the rotor exits to the operating mode (speed frequency). To choose the capacitor for the engine in this case, you should know that its calculated voltage exceeds that one in the working capacitor by 1.5 times, the capacity is 2.5-3 times.
It is allowed to connect more than one capacitor. If you connect them in parallel, then the container will increase, which is convenient for calculations.
After turning on the engine, the first time it is necessary to follow its operation. He should not heat up too much. If it is not clear which capacitors for the electric motor are used in this case, then the correct answer is with a smaller capacity. The working voltage is at least 450 V. In order for the engine to work efficiently, it is necessary not only to correctly determine all the parameters of the capacitor used, but also to take into account the conditions of its load or work.
Connecting a three.phase engine to a single.phase network according to a star scheme
I’ll start with a warning: even experienced electricians during operation make mistakes called the “human factor”. What can we say about home masters.
Therefore, I recommend that the voltage supply to the assembled circuit is required only through a separate automatic SF circuit breaker, properly selected by load. He will save life and health.
Star connection scheme is shown in the picture.
The ends of the windings are collected at one point with horizontal jumpers inside the terminal box. No external wires are connected to it.
Phase (through an automatic circuit breaker) and zero household wiring are fed to two different terminals of the start of windings. A parallel chain of two capacitors is connected to a free terminal (in the figure H2): CP. worker, joint venture. launch.
The working capacitor is connected by the second lining rigidly with the phase wire, and the starting. through the additional switch SA.
When starting the electric motor, the rotor must be untwisted from the rest of the rest. He overcomes the friction efforts of bearings, counteracting the environment. For this period it is necessary to increase the magnetic flux of the stator.
This is done by increasing current through an additional chain of starting capacitor. After the rotor exits to the operating mode, you need to turn it off. Otherwise, the starting current will overheat the engine winding.
Perform the shutdown of the starting chain by a simple switch is not always convenient. To automate this process, you use circuits with relay or starters working in time.
Among the masters of home.made, the starting button from Soviet launcher.type washing machines is popular. She has two contacts built, one of which, after turning on, is turned off automatically with a delay: what is needed in our case.
If you look carefully at the principle of supplying single.phase voltage, you will see that 220 volts are attached to two sequentially connected windings. Their total electrical resistance is folded, weakening the value of the current current.
Connection of a three.phase engine to a single.phase network according to a star scheme is used for low.power devices, is characterized by increased energy losses up to 50% of the three.phase power system.
Scheme Triangle: Advantages and disadvantages
Connecting the electric motor by this method involves the use of the same external chain as the star. Phase, zero and middle point of the lower heating of the capacitors are mounted sequentially on three jumpers of the terminal box.
Due to the switching of the conclusions of the windings according to the triangle scheme, the outdoor voltage 220 creates a larger current in each winding than that of the star. Here are less energy losses, above efficiency.
Connection of the engine according to the triangle scheme in a single-phase network allows you to use up to 70-80% of the power consumption.
For the formation of a phase.drive chain, it is necessary to use the smaller capacity of working and starting capacitors here.
When the engine is turned on, it can start rotation in the wrong direction that is required. He needs to make him a reverse.
To do this, it is enough in both schemes (stars or triangle) to change the wires coming from the network on the terminal block. The current will flow along the winding in the opposite direction. The rotor will change the direction of rotation.
Dismantling of the tool
Almost all malfunctions of electrical disk saws cannot be eliminated without disassembling the device partially or completely. Full disassembly of a hand.based electrical saw using the Interskol unit is performed in the following order.
- Unscrew the adjusting screws of the angle and depth fixed on the sole of the device.
- Press the Reducer shaft button and use a hexagonal key to unscrew the bolt holding the saw disk.
- Putting the lower protective casing to the side, remove the circular disk.
- To remove the support sole, first unscrew the fasteners on its lower side.
- Further, it is necessary to remove the ziger ring with two screwdrivers, a stopping rod on which the sole rotates to change the angle.
Insert the screwdriver into the gap between the hull and the sole, then push it away and remove it.
Next, you should disconnect the gearbox of the unit by twisting 2 screws.
Having removed one half of the handle, you will see the module of the smooth start of the engine and the start button.
On this, the full disassembly of the disk saw ends.
Do.it.yourself disk saw repair
When starting to repair the unit with your own hands, it is not necessary to disassemble it completely to clarify the reasons for the breakdown. Some malfunctions are characterized by specific symptoms by which you can determine the problem and already purposefully disassemble this or that part of the device.
The saw does not turn on
If when you press the start button, the engine of the unit “is silent”, then the first thing to focus on is the network cable, provided that there is electricity in the outlet (connect the device to another outlet for verification).
To check the electric cable, you need to disconnect the handle. This will help to get to the contacts to which the wires of the network cord are soldered. Further, with the help of a tester, call each wire, pressing one probe to the soldered contact, and the second. to the pin of the fork.
If the network cable is intact, then in search of a malfunction do the following.
- Blind the entire chain by the tester, starting from the cable entrance to the unit to the launch button. You should also check the contacts of the button at its input and output with the key pressed. In normal condition, the torn chain should be closed. Call all the wires after the button going to the engine brushes.
- If everything is in order with the conductors, check how much the electrodes of the brushes have worn out. After wear of the electrode 2/3 of the initial size, it should be replaced. Brushes, regardless of how much each of them has worn out, change in pairs.
- If the brushes are in good condition, then, most likely, the engine has failed. In his windings, a cliff or inter.flip.circuit could occur. In this case, it is better to entrust the engine repair to specialists who will rewind the stator coils or anchor.
The engine heats up
The unit can heat up excessively, for example, with its intensive use, as well as when sawing hard wood or the use of a saw disk with a large number of teeth, when the load on the engine increases significantly. Also caused by overheating of the malfunctioning motor associated with the windows of the stator and anchor, which are eliminated only in the service center.
Brushes are burning
Strong sparking from under the brushes is caused by excessive wear, when the spring can no longer press the electrodes to the collector with the required force. To replace the brushes, you need to disconnect the engine cover or remove them through special holes in the engine housing (depending on the power plant model).
Jammed the shaft during operation
This malfunction may happen when for any reason, a stopper is pressed during the tool. It is designed to fix the shaft when replacing equipment and should be used after a complete stop of the engine. Otherwise, the Stop Stop rod breaks down, and its debris fall into the engine, causing jamming. There are frequent cases when this leads to deformation of the anchor shaft. Also, the consequence of pressing on the stopper can be the split of the gearbox body, the fragments of which can damage the gears and provoke their jamming. To solve the problem, you will need to replace the anchor, a stopper leading (large) gear of the gearbox and its body.
In some cases, the gearbox can jam with the complete destruction of the bearing.
The saw stops in the process
The engine stops in most cases cause a cavity worn electrical brushes. Когда контакт между электродом щетки и ламелями коллектора нарушается, происходит выключение агрегата.
Often, when buying brushes for a given apparatus, products with a short conductor connecting the electrode to the plate come across. This conductor is located inside the spring and does not allow it to be completely imprisoned. Когда электрод изнашивается до определенной длины, то прижим его к коллектору прекращается, поскольку этому препятствует короткий проводник. If you, examining the brush, find that it is not yet worn out and the spring is not unclenched, then the part should be replaced.
The gearbox body is very hot
The rapid heating of the gearbox occurs if the shaft bearing is unusable, on which the gear is fixed and the equipment is attached. In this case, in addition to heating, you can replace the appearance of extraneous noises in this unit node. It is necessary to disassemble the gearbox and change the bearing. The gearbox will also heat up if it is not enough lubricant or it is completely absent.
The saw does not gain power
If during the use of the unit you noticed a drop in its power, then it is first recommended to check the voltage level in the network. Sometimes even a slight drop can negatively affect the power of the power tool.
Also, loss of power can be observed with wear of the bearings of the anchor or gearbox bearing. In this case, extraneous noises will be heard, previously not characteristic of this unit. By their localization, you can determine where the problem bearing is located. in the gearbox or engine. To replace bearings, you will need to disassemble the disk saw. How to do this was described above.
If during the operation of the unit is not heard, the engine still poorly develops momentum and power, then pay attention to its collector. Usually on it you can see a circular spark (fire ring). This can happen due to the inter-flip closing of the anchor coil or the accumulation of dirt between the collector lamps.
Expand the engine housing and carefully inspect the collector (the place where the electrodes of the brushes glide). It consists of parallel stripes (lamellas). There is a small gap between them. When this gap is clogged with conductive graphite dust formed during the wear of the brushes, a short circuit occurs between the lamels, and a burning ring around them appears.
The problem will be solved by replacing the worn brushes and cleaning the gaps between the lamellas using a toothbrush, cotton wool and alcohol, followed by polishing the plates with fine sandpaper.