How to connect the controller angle grinder. Other features: soft start and more

Instructions for making a speed regulator for angle grinder with your own hands

The integrated option to regulate the number of revolutions of the wheel will make it possible to gently work materials such as wood or plastic. At lower speeds, increased comfort and safety. Such an option is most practical in radio and electrical installation, service stations and studios engaged in restoration.

over, among professionals who use power tools, there is a perception that the more trivial is arranged attachment, the more reliable it is. And it is desirable to remove the additional service “stuffing” beyond the boundaries of the angle grinder. With this approach, maintenance of the equipment is greatly simplified. In this regard, some firms deliberately produce remote individual electric regulators, which are connected to the mains cable angle grinder.

The main malfunctions of the angle grinder and their causes

According to statistics, most cases of failure of the angle grinder associated with the electrical part of the device. Some failures may be minor, which allows the repair of angle grinder with their own hands. But, for example, if the motor windings burn out, the repair of the angle grinder can only be made by a specialist.

angle grinder does not turn on

The reasons for the fact that the angle grinder does not turn on, can be the following:

  • the electrical plug is faulty;
  • The electric cable is defective;
  • The start button is broken;
  • The contact between the power cable and the button is broken
  • breakage of the contact wire of the electric brush;
  • Heavy wear and tear of the electric brushes;
  • Failure of rotor or stator windings.

the angle grinder does not develop speed

The causes of the angle grinder not picking up speed may be different.

  • Breakage of the block of speed regulation. To check this version, connect the engine of the machine directly, without the regulator, and check the operation of the device.
  • Electric cable failure due to permanent kinks or mechanical damage. Because of this, the damaged wire begins to warm up under load, and the engine speed drops.
  • The collector is contaminated with dust. Remove the dirt with methylated spirits.
  • Problems with the brushes. They may be worn out or have a short contact wire as shown in the following photo.

The brush is half worn out but is still serviceable. The short contact wire prevents the spring from pressing the electrode against the collector. This situation can also be the reason why the angle grinder does not work normally.

The electric motor is heating up

Causes of the angle grinder being hot, may be.

  • Improper operation of the unit. As a result of overloading, the electric motor can become very hot, which often leads to winding burnout.
  • Destruction of the bearings on the armature. As a result, the rotor is caught in the stator, making it difficult to run the motor and the windings overheat. The problem can be solved by replacing the bearings.
  • The ventilation ducts through which the air for cooling the motor is sucked in are clogged. The ventilation openings must be cleaned of dust.
  • Breakage of the impeller that cools the motor. It is mounted on the rotor, on the opposite side to the collector. If the impeller is broken, it must be replaced with a new one.
  • Inter-turn short circuits in stator and rotor windings. Rewinding of winding coils or replacement of such parts with new ones is necessary.

angle grinder sparks

If you notice a strong spark when you turn on the angle grinder in the area where the collector is located, then the causes of this trouble may be.

  • Armature winding damage: breakage of one or more winding sections, inter-turn short circuit. At such breakdowns there is an increased noise, the engine speed drops and brushes burn.
  • The contact between the collector plates and the winding is broken.
  • Weak brush pressure. Under long angular grinder modes, the springs overheat and can “anneal” and lose their elasticity.
  • Unbalanced motor rotor.
  • Cylindrical surface of the collector disturbed. This sometimes occurs after rewinding, if the armature is not turned on the lathe, but installed immediately in the machine. In that case, you may also observe that the brushes spark excessively.
  • The insulation between the lamellas of the collector is broken. Also, graphite clogging of the raceway grooves or a breakdown between the lamellae may occur.
  • Bearing wear and tear that causes rotor runout also causes excessive brush arcing.
  • Breaking of the armature shaft geometry. This usually happens when the motor is disassembled carelessly and the shaft is bent.
  • The wrong brand of graphite brushes are installed. the brushes are selected according to the expected speed and voltage.
  • Lifting one or more blades causes brushes to burn out quickly. It happens because of overheating of the engine in prolonged operation. As a result, the glass mass that forms the base of the collector softens and the lamellas start to rise. Because the blades are up, the brushes wear out very quickly.

Making a speed regulator with your own hands

Trying to adapt a regular dimmer m to adjust the brightness of the lamp does nothing. Firstly, these devices are designed for a completely different load. Secondly, the principle of operation of the dimmer is not compatible with the control of the electric motor winding. That’s why you have to install a separate circuit and figure out how to put it in the tool body.

The simplest thyristor speed controller can be easily made by yourself. To do this you need five radio elements, which are sold at any market.

The wiring diagram of a thyristor speed controller for your tool

Compact design allows you to place the circuit in the housing of angle grinder without compromising ergonomics and reliability. But this circuit can’t hold the torque if the rpm drops. Option is suitable for reducing the speed when cutting thin tin, polishing work, processing of soft metals.

If your angle grinder is used for processing stone, or it is possible to install disks larger than 180 mm, you need to build a more complex circuit, where as the control module is used chip KR1182PM1, or its foreign analogue.

Circuit diagram of the speed control using the chip KR1182PM1

Such a scheme controls the amperage at any RPM, and allows you to minimize the loss of torque when they are reduced. It also protects the engine and increases engine life.

The question of how to make the tool rotation control arises in the stationary position of the tool. For example, when using an angle grinder as a circular saw. In this case, the regulator is equipped with a connection point (automatic device or socket), and the speed is adjusted remotely.

Regardless of the method of execution, the speed controller angle grinder expands the capabilities of the tool and adds comfort when using it.

You have an angle grinder, but no speed controller? You can make it yourself.

RPM controller with your own hands

Speed regulator is not installed in all types of hammers. You can make a block for speed control with your own hands or buy a ready-made.

Factory speed controllers for angle grinders: photo examples

Such regulators have a simple electronic circuit. So it is not too difficult to make an analog with your own hands. Let’s consider, what is assembled the speed controller for lathes up to 3 kW.

Making a printed circuit board

As the scheme is very simple, it makes no sense to install a computer program for processing electrical circuits because of it alone. All the more so because you need a special paper for printing. And not everyone has a laser printer. So let’s take the simplest way of making a printed circuit board.

Take a piece of textolite. Cut off the necessary size for the chip. Sand and degrease the surface. Take a marker for laser discs and draw a diagram on the textolite. In order not to make a mistake, you should first draw with a pencil. Next, let’s start etching. You can buy chlorine iron, but after that the sink is badly washed. If you accidentally drop it on your clothes, you will be left with stains that cannot be completely removed. So we will use the safe and cheap method. Prepare a plastic container for the solution. Pour 100 ml of hydrogen peroxide. Add half a tablespoon of salt and a sachet of citric acid to 50 g. The solution is made without water. You can experiment with the proportions. And always make fresh mortar. Copper should be all drained out. It takes about an hour. Rinse the board under running well water. Drill the holes.

We can make it even simpler. Draw a diagram on paper. Tape it to the cut out textolite and drill holes. Only after that should you draw the circuit with a marker on the board and etch it.

Wipe the board with rosin flux or the usual rosin solution in isopropyl alcohol. Take some solder and tin the tracks.

Mounting the electronic components (with photo)

Prepare everything that comes in handy for mounting the board:

Bite off the four pins and solder them into the board. Then install the diistor and all the other parts except the variable resistor. Solder the triac last. Take a needle and a brush. Clean up the spaces between the tracks to remove any possible short circuits. Attach the free end of the triac to the aluminum heat sink for cooling. Roughen the fixing area of the element with fine sandpaper. Take a piece of thermal grease KPT-8 and apply a small amount of it to the heat sink. Secure the triac with the screw and nut. Since all parts of our design are energized, we will use a knob of insulating material to adjust. Put this on the variable resistor. Using a piece of wire, connect the outermost and the middle terminals of the resistor. Now solder two wires to the last solder pins. Solder the opposite ends of the wires to the corresponding pins on the printed circuit board.

connect, controller, angle, grinder

You can make the whole installation hinged. To do this, we solder the chip parts to each other directly using the tabs of the elements themselves and wires. Here you also need a heat sink for the triac. It can be made from a small piece of aluminum. Such a regulator takes very little space and can be put in the housing of an angle grinder.

If you want to install LED in the speed controller, use another circuit.

Diagram of the regulator with LED indicator.

Diagram of the regulator with LED indicator

Regulator with LED assembled.

Regulator with LED light assembled

This block is designed for low-power drills, so the triac is not mounted on the radiator. But if you want to use it in a power tool don’t forget about the aluminum plate for heat dissipation and the triac bta16.

Testing the electronic block

Before connecting the block to the tool, let’s test it. Take an overhead socket. Wrap two wires into it. Connect one to the circuit board and the other to the power cable. There is one more wire left at the cable. Connect this to the circuit board. It turns out that the regulator is connected in series with the load. Connect a lamp to the circuit and check the operation of the tool.

Connecting the regulator to an angle grinder

Speed regulator is connected to the tool in series.

If there is a free space in the handle of the angle grinder, you can put our unit there. The circuit, assembled by hinged mounting, is glued with epoxy, which serves as an insulator and protection against shaking. Insert the variable resistor with the plastic handle outside to control the speed.

Install the regulator inside the angle grinder’s body

The electronic unit, assembled separately from the angle grinder, is placed in a housing made of insulating material, as all elements are under mains voltage. A portable socket with power cord is screwed to the housing. The knob of variable resistor is outside.

The controller is plugged into the mains and the tool into a portable socket.

Advantages of universal angle grinder

Metabo angle grinder (angle grinder) WEV 10-125 Quick 600388000 (in box). 220Volt photo

Not always the usual angle grinder without additional options can solve the problem of processing certain types of materials, the working tool is not adapted to work effectively at speeds that gives an angle grinder without a speed regulator. The problem of choosing the right mode is particularly acute for users involved in sanding, scraping, polishing various materials. To perform the work, sometimes you have to look for another tool with suitable characteristics.

The versatility of the angle grinder with speed control is precisely the ability to set the speed of rotation, for example, cord brushes for cleaning. When performing grinding operations increases the contact area between the working tool and the work surface, which requires the use of grinders with increased power. Such angle grinder with installed additional options perform almost any kind of work with different materials.

Selection criteria angle grinder with electronic speed control

An angle grinder with an electronic speed regulator is not a cheap purchase option. You should clearly understand the amount of work, in which you need to change the speed of the working tool. Convinced of the validity of the purchase of angle grinder with such an option, selected specifications angle grinder in combination with the capabilities of electronic control unit to affect the selection of operating mode. Detailed information about the selection criteria can be found at the link “Choosing an angle grinder with speed control”.

Connecting the soft starter

Electronic speed controller is mainly needed by home craftsmen to expand the capabilities of the angle grinder in terms of grinding and processing of soft materials. Professionals generally use specialized tools for certain applications and only use angle grinders for their intended purpose. The situation is different with the soft starter. For domestic tools with low power this option is useful, but not necessary. But for professional grinders with drives over 1000 W it is of vital importance. In addition to the performance improvements outlined above, the soft starter is extremely important for the safety of the operator. a 2000 watt angle grinder with Ø230 wheel weighs 5÷6 kg, and requires a certain amount of effort and stability to hold it during the start-up jerk.

Soft-start unit can be purchased in retail chains and independently mounted inside the housing of any angle grinder. The video below shows its installation on a new powerful angle grinder, bought by the author for grinding works. This video is also interesting because its author with the help of an arrow device demonstrates the size of the current jump when turning on the angle grinder first without a soft start, and then already with this device.

The most advanced control device for the angle grinder is the RPM under load system, which also serves as a speed regulator and ensures a soft start. On the internet you can find a circuit for making such a device on the U2010B chip, but it is quite complicated even for those who have basic radio amateur skills. Is it possible to buy a ready made RPM unit and how much does it cost?? If anyone can answer this question, please share the information in the Комментарии и мнения владельцев.

How to make a soft start and RPM controller for angle grinder

All budget options of the angle grinder have several disadvantages. First, there is no soft start system. This is a very important option. Surely all of you have plugged this powerful electric tool into the network, and during start-up you saw how the light bulb, which is also connected to this network, diminishes in intensity.

This phenomenon is due to the fact that powerful electric motors at the startup consume huge currents, due to which the voltage sags. It could even break the tool itself, especially a Chinese-made one with unreliable windings that might burn out one day during start-up.

In other words, a soft start system protects both the mains and the tool. Furthermore, a strong kickback or jolt occurs when you start the tool and this would certainly not be the case with a soft start.

Secondly, there is no speed regulator, which will allow the tool to work for a long time without loading it.

The diagram below is from an industrial design:

It is implemented by the manufacturer in expensive devices.

You can connect not only “angle grinder” to the circuit, but, in principle, any device. drill, milling and lathe. But given that it’s a collector motor that’s supposed to be in the tool.

This will not work with asynchronous motors. It needs a frequency converter.

So, we need to make a printed circuit board and assemble the circuit.

As a regulating element a double operational amplifier LM358 is used, which controls the triac by means of a transistor VT1.

So, the power element in this circuit is a powerful triac, type BTA20-600.

I couldn’t find such triac in the store and had to buy BTA28. It’s a little more powerful than the one in the schematic. In general, for motors with power up to 1 kW you can use any triac with a voltage not lower than 600 V and a current of 10-12 A. But you’d better have some reserve and buy triacs for 20A. They cost a penny anyway.

The triac will get hot during operation, so you need to put a heat sink on it.

To avoid questions about the fact that the motor, when started, can draw currents that are much higher than the maximum current of the triac, and the latter can simply burn out, remember that the circuit has a soft start, and the inrush currents can be ignored.

Everyone is probably familiar with the phenomenon of self-induction. This effect is observed when a circuit to which an inductive load is connected is opened.

connect, controller, angle, grinder

This is the same in this circuit. When the power to the motor is abruptly cut off, the inductive current from the motor can burn out the triac. And the snubber circuit dampens inductance.

The resistor in this circuit has a resistance of 47 to 68 ohms and a power of 1 to 2 watts. Capacitor is a film capacitor for 400 V. Self-induction as a side effect in this version.

Resistor R2 provides quenching for the low voltage control circuit.

The circuit itself is in some way both a load and a stabilizing link. Due to this it is possible not to stabilize the power supply after the resistor. Although there are similar circuits on the net with an additional Zener diode, it makes no sense to use it, because the voltage across the pins of the operational amplifier supply is within the normal range.

Possible replacements for low power transistors can be seen in the following picture:

The circuit board mentioned earlier is just the board for the soft starter, and it has no components for speed control. This is done on purpose, because in any case the regulator has to be wired.

The tuning of the regulator is done with a 100 kohm multi-turn trimmer resistor.

And the basic setting is already done with resistor R5. It is worth saying that this kind of circuit will not allow adjustment from zero, only from 30 to 100%.

If one needs a more powerful regulator, it can be assembled according to the following scheme:

How to make an adjustment for an angle grinder at home, homemade options

If a person wants to get a free adjustment for the angle grinder, you can try to make it yourself. However, before you do this, you need to familiarize yourself with how to properly make it.

Without loss of power

Many people dream of creating a homemade device to regulate the speed without further loss of power. However, in fact, it is almost impossible to make them. The fact is that such regulators should be equipped with special sensors. They independently monitor how fast the circle rotates and, if necessary, correct the speed. Only manufacturers of angle grinders can make such devices.

Important! At home we can make regulators on semiconductor circuits. They do not guarantee full power retention when you change the RPM.

Testing the electronic device

People who have managed to assemble the regulator themselves should test it before connecting it to the angle grinder. This must be done to verify the performance of the manufactured module.

How to Be Safe Using an Angle Grinder. Switches. From Toolstop

To check the functionality of the regulator at home, you need a superimposed electrical socket. Two wires are installed in it, one of which is connected to the board. The second must be connected to the mains cable.

When all the wires are connected you have a daisy chain. To test the regulator, connect a light bulb to the circuit and try to reduce its power. If its brightness began to decrease, then the electronic device works and you can put it in the angle grinder.

How to increase/decrease the rotational speed of the saw blade

There are situations where you need to not only turn the speed down, but also increase the speed. In this case, it is not necessary to understand how to make an angle grinder with speed control with your own hands. It is much easier to buy a universal Chinese regulator, with which you can change the speed.

Such devices are sold in separate plastic boxes. They are equipped with a socket for connecting an angle grinder and a cord with a plug to connect the device to a power source.

Additional information! It is quite convenient to use such modules. You just need to connect an angle grinder through the installation and select the mode of operation on the regulator.

Angle grinder Makita 9565CVR. Should I Buy? With my own eyes

How to connect, connect

The device for reducing and increasing speeds can be connected in different ways. There are two methods that are used most often when connecting the regulator:

  • As an external control device. It is recommended to place such modules outside the housing of the power tool. Quite often people install boards on semiconductors to regulate the power of an angle grinder in the mains carry.
  • Installation inside the tool body. This method is used very rarely. The fact is that it is quite problematic to mount the device in the housing because of the small amount of free space. Also, this method is not popular due to the fact that the regulator will often overheat in the housing of the angle grinder.

Further information! If you can not connect the regulator yourself, it is necessary to entrust this work to a professional.

How to disable, remove the voltage sensor

There are situations when it is necessary to get rid of the connected module to adjust the speed. Most often this happens if the device malfunctions and because of this it is not possible to use the angle grinder. In that case, there is only one thing to do. detach the sensor.

It is easy enough to disconnect the regulator. If it is built into the tool, you have to remove the housing and carefully disconnect all the wires. When using an outdoor module, everything is even simpler. It is necessary to disconnect it from the socket and the angle grinder.

How to make a turn regulator with your own hands

So as not to complicate the understanding of the principle of operation with complicated terms, the principle operation of the circuit can be explained simply. It has a sensitive element that reads the value of the load. Depending on the value read, this element controls the shut-off device.

The principle of operation is similar to that of a water faucet. You are in this case the sensor which controls the water tap. The water flow becomes more or less depending on need. The same process occurs with the current.

It is necessary to properly understand the point that we can not increase the speed of rotation more than that specified in the characteristics of the angle grinder. We can only turn it down. If the maximum RPM is 3000, then the range in which we can adjust the RPM will be below this value.

In the simplest case, you can use a thyristor controller circuit. It will both sense and regulate. Two-in-one. This circuit has only five parts. It’s very compact and easy to fit in a case. Such a regulator will not work from zero RPM, but it is not necessary for angle grinder.

If you need lower RPM in your work, you should use another circuit on an integrated circuit, where the blocking element will be a triac. It can control the RPM from nearly zero to the desired RPM.

In both circuits, the main load is on the shut-off valve. It should be designed for voltages up to 600V and currents up to 12A. If your grinder is more powerful than 1 kW, the shutoff element must be able to withstand loads up to 20A.

All thyristor circuit parts can be placed on a printed circuit board or simply mounted. The second option is to solder the parts on the printed circuit board. A printed circuit board can be made using various methods. It can be etched from foil-plated textolite, or even cut out with a cutter, but it is very crude. In principle you can ask an acquaintance radio amateur to make it for a very modest fee.

The radio electronic elements are inserted into the fabricated circuit board. They can be purchased in specialized stores or at radio markets. Each component must be the same in both rating and power rating. Thyristors or triacs should preferably be mounted on a heatsink, aluminum or copper.

When the finished board is ready, you need to choose a convenient place in the case of the angle grinder for its installation. It is desirable to install it so that it is convenient to use and does not interfere in the process of work.

Before you install the circuit in the machine, you need to test it. To do this, instead of an angle grinder on the output should be connected to an ordinary incandescent lamp. The 60 to 40 watt 220 V model is the right choice. The workability will be evident by the change in the glow of the light bulb.

Now it remains to mount the device in the selected place and make a test run of the angle grinder. It will stop tearing out of your hands during start-up, and the speed will be regulated smoothly by turning the regulator.