How to Connect a Capacitor to an Angle Grinder

Soft start for do-it-yourself angle grinder: diagram. Soft starter angle grinder, connection

Many power tools fail due to engine wear. Modern models of grinders have a soft starter. Due to him, they are ways to work out for a long time. The principle of operation of the element is based on a change in the operating frequency. In order to learn more about the starter, it is worth considering the scheme of the standard model.

How to Connect a Capacitor to an Angle Grinder

Soft starter

The standard soft starter angular grinder consists of a triac, rectification unit and a set of capacitors. To increase the operating frequency, resistors are used that pass current in one direction. The starter is protected by a compact filter. The rated voltage of the models is maintained low. However, in this case, much depends on the maximum power of the motor, which is installed in an angle grinder.

How to connect a model?

Connecting a soft start angle grinder through an adapter. Its input contacts are connected to the rectifier unit. It is important to determine the zero phase in the device. To fix the contacts you will need a blowtorch. Check the starter through the tester. First of all, negative resistance is determined. When installing the starter, it is important to remember the threshold voltage that the device can withstand.

Device diagram for angle grinder with triac 10 A

The soft start circuit of a self-made angle grinder, involves the use of contact resistors. The polarity coefficient of the modifications, as a rule, does not exceed 55%. Many models are made with locks. A wired filter is responsible for protecting the device. To pass current, low frequency transceivers are used. The process of lowering the threshold voltage is carried out on a transistor. The triac in this case acts as a stabilizer. When connecting the model, the output impedance with an overload of 10 A should be about 55 ohms. The starter plates are semiconductor based. In some cases, magnetic transceivers are installed. They cope well with low revs and can support the rated frequency.

Model for grinders with triac on 15 A

Soft start for an angle grinder with 15 A triacs is universal and is often found in low power models. The difference between devices is low conductivity. Scheme (device) for soft start angle grinder involves the use of contact-type transceivers that operate at a frequency of 40 Hz. Many models use comparators. These elements are set with filters. The rated voltage for starters starts at 200 V.

Starters for grinders with a triac on 20 A

Devices with 20 A triacs are suitable for professional grinders. Many models use contactor resistors. First of all, they are able to work at high frequency. The maximum temperature of the starters is 55 degrees. Most models have a well-protected case. The standard scheme of the device involves the use of three contactors with a capacitance of 30 pF or more. Experts say that devices stand out for their conductivity.

The minimum frequency for starters is 35 Hz. They are able to work in a direct current network. Modifications are connected via adapters. For 200 W motors, such devices are well suited. Filters are often installed with triodes. The sensitivity indicator for them is not more than 300 mV. Quite often there are wired comparators with a protection system. If we consider imported models, then they have an integrated converter, which is installed with insulators. Current conductivity is provided at around 5 microns. With a resistance of 40 ohms, the model is able to stably maintain high speeds.

600 W Angle Grinder Models

For 600 W grinders, starters with contact triacs are used, in which the overload does not exceed 10 A. It is also worth noting that there are many devices with plates. They are distinguished by security and are not afraid of high temperature. The minimum frequency for grinders at 600 W is 30 Hz. In this case, the resistance depends on the installed triode. If it is used of linear type, then the above parameter does not exceed 50 Ohms.

If we talk about duplex triodes, then the resistance at high speeds can reach 80 Ohms. Very rarely, models have stabilizers that work from comparators. Most often, they are attached directly to the modules. Some modifications are made with wire transistors. They have a minimum frequency starts from 5 Hz. They are afraid of overloads, but are able to maintain high speed at a voltage of 220 V.

Devices for grinders at 800 watts

800 W angle grinder works with low frequency starters. Triacs are often used at 15 A. If we talk about the model circuit, then it is worth noting that they use expansion transistors, in which the current throughput starts at 45 microns. Capacitors are used with and without filters, and the capacitance of the elements is no more than 3 pF. It is also worth noting that starters differ in sensitivity.

If we consider a professional angle grinder, then modifications for 400 mV are suitable for them. In this case, the current conductivity may be low. There are also devices with variable transistors. They quickly warm up, but they are not able to maintain high speeds with an angle grinder, and their current conductivity is about 4 microns. If we talk about other parameters, then the nominal voltage starts from 230 V. The minimum frequency for models with broadband triacs is 55 Hz.

Starters for grinders 1000 W

Actuators for these grinders are manufactured on triacs with an overload of 20 A. The standard circuit of the device includes a triode, a stabilizer plate and three transistors. The rectifier unit is most often mounted on a wired basis. Capacitors can be used with or without a filter. The minimum frequency of a conventional model is 30 Hz. With a resistance of 40 ohms, starters are capable of supporting large overloads. However, problems may occur at low revolutions of the angle grinder.

How to make a starter with a triac TS-122-25?

Making a smooth start with the TS-122-25 simistor for a do-it-yourself angle grinder is quite simple. First of all, it is recommended to prepare a contactor resistor. Capacitors will require a single pole type. In total, three elements are installed in the starter. The capacitance of one capacitor should not exceed 5 pF. To increase the operating frequency, the contactor on the plate is soldered. Some experts say that it is possible to increase conductivity due to filters.

The rectifier unit is used with conductivity from 50 microns. It is able to withstand large overloads and can provide high speeds. Next, to assemble a smooth start on an angle grinder with your own hands, a thyristor is installed. At the end of the work, the model is connected through an adapter.

Assembly of the model with triacs of the VS1 series

To assemble on the triac VS1 a soft start for an angle grinder with your own hands, you can use several rectifier blocks. Capacitors for the device are suitable for linear type with capacitance from 40 pF. To start assembling the modification is soldering resistors. Capacitors are installed in series between insulators. The rated voltage of a high-quality starter is 200 V.

Next, to make a soft start for the angle grinder with your own hands, a prepared triac is taken and soldered at the beginning of the chain. The minimum operating frequency should be 30 Hz. In this case, the tester must display a value of 50 ohms. If there are problems with overheating of the capacitors, then you need to use dipole filters.

Video: How to Connect a Capacitor to an Angle Grinder

Model for grinders with regulator КР1182ПМ1

To assemble a soft start with the KR1182PM1 regulator for an angle grinder with your own hands, a contact thyristor and a rectifier block are taken. The triode is more appropriate to apply to two filters. It is also worth noting that three capacitors with a capacitance of at least 40 pF will be required to assemble the starter.

The sensitivity index of the elements must be 300 mV. Experts say that the triac can be installed behind the lining. It should also be remembered that the threshold voltage should not fall below 200 V. Otherwise, the model will not be able to work with reduced speed angle grinder.

Stator winding connection

Hello, traditionally, a circuit has two work elements. Connection is made in series. To do this, use the appropriate cable. It is connected to a network with a voltage of 220 V.

To turn the windings on or off, a stator is used. In this case, for normal operation, each winding must be connected to a graphite brush. over, they are connected in parallel. After that, the electric circuit is directed to the rotor.

Attention! Closing occurs on the contact elements of the collector.

Anchor winding consists of many windings. At the same time, only two go to graphite brushes. In most cases, the device fails just because the electrical circuit is interrupted.

How to connect

In order to find contacts for connection, use a multimeter. With it, you can find the malfunction, if any. First, test the input section. Then you need to ring the whole chain. To accurately determine the conductivity, the resistance should be minimal.


When you find the desired contact with a multimeter, you can connect. For clarity, I recommend that you watch the video below. It talks pretty well about solving problems with the stator. There is also detailed instruction on how to deal with part malfunctions.

Soft start angle grinder. Scheme

Soft start the angle grinder circuit, which is built on the KR1182PM1 microcircuit (phase control microcircuit), allows you to smoothly and safely start not only the angle grinder, but also any powerful electric tool. The soft start circuit is quite simple and does not require any configuration.

It is possible to include any power tool that runs on 220 volt power without any changes to the circuit. Starting and turning off the electric motor, the angle grinder is carried out by the electric button of the electric tool itself.

The soft starter for the angle grinder is shown in the figure below. The XP1 connector is connected to a 220 volt electrical outlet, and an angle grinder is inserted into the XS1 (outlet) plug. It is possible to put and connect in parallel several sockets for power tools that operate alternately.

When the power tool button is pressed, the circuit closes and a voltage is applied to DA1 (phase regulator). In this case, the capacitor C2 begins to charge, which leads to a smooth increase in voltage on it. The result of this is a delay in opening the thyristors (inside) of the regulator, and with them the VSI triac. The delay decreases in each half-cycle of the mains voltage, as a result of which the voltage flowing through the electric motor of the angle grinder increases smoothly and, consequently, its revolutions smoothly increase.

With the value of the capacitor C2, which is indicated on this diagram, a smooth set of revolutions from the minimum amount to the nominal takes about 2 seconds, which is quite enough to protect the power tool from dynamic and thermal shock, and at the same time ensure comfortable operation with an angle grinder.

After turning off the electric motor, the angle grinder, C2 capacitance discharges through resistance R1, and after 3 seconds the soft start circuit, the angle grinder is ready for a new start. By changing the constant resistance R1 to variables, it is possible to smoothly change the power supplied to the electric motor. Resistance R2 reduces the current flowing through the control electrode of the triac, and capacitances C1 and C3 reduce the radio components of a typical connection circuit of the KR1182PM1 microcircuit. All resistances and capacitances are soldered directly to the terminals of the KR1182PM1 chip.

It is possible to use a triac any one with a maximum operating voltage of more than 400 V and with a maximum current of at least 25 amperes (depending on the power, an angle grinder). Due to the soft start of the electric motor, the angle grinder, its starting current is not more than the rated current. The current reserve is needed only in case of jamming of the power tool. The soft start circuit has been tested with tools up to 2.2 kW. Since the KR1182PM1 microcircuit guarantees the flow of current in the circuit of the electrode (control) of the triac VS1 throughout the active half-period, there are no restrictions on the minimum power of the connected load.

Angle grinder device

The device of an angle grinder depends on the design features of the location of the modules in the case of an angle grinder, which can be different depending on the model used and the manufacturer.

Not so long ago, we discussed in detail how to disassemble an angle grinder quickly and independently for repair and maintenance work. For the same purposes (for repair and maintenance) we will need to know the angle grinder device, which is inextricably linked with the disassembly process. Despite the fact that the models of grinders and manufacturers are very different, they all contain, in principle, the same components and modules.

Picture 1. cut angle grinder

Therefore, the functional device for all types of grinders is almost the same and can differ as a rule only by small design features. the angle grinder is equipped with the same modules and assemblies, which we will examine in more detail below. We list the most basic of them, which are assembled in one design under the cover of the case and constituting a device called an angle grinder.

Read more on the site how to disassemble a drill.

The main modules that the angle grinder is equipped with

1. Convenient and shockproof case.

2. An electric motor consisting of a stator and a rotor.

3. Noise suppression filter. This is a device that suppresses the high-frequency noise resulting from it during operation of the electric motor and thereby preventing it from spreading in the supply network.

4. A gearbox consisting of gears and allowing to rotate the axis of rotation by 90 degrees.

5. Trip clutch. Such a device is usually equipped with a large angle grinder. The device allows you to prevent the occurrence of a reverse shock in case of sudden jamming of the cutting disc in the material. It consists of two disks tightly pressed against each other, which prevent a sudden stop of the rotation of the rotor shaft and also the loads that arise during this.

6. Spindle speed adjustment device. Unfortunately, not all grinders are equipped with such a useful device.

7. Buttons for starting the electric motor and soft start (not all models are equipped). The button allows the tool to gain working speed not immediately but gradually, thereby preventing possible injuries and the load on the electric motor.

8. The SJS system allows you to protect the motor from extreme loads arising from the sudden jamming of the cutting wheel in the material. True, not all angle grinders are equipped with such a device by manufacturers.

9. A protective cover allowing the operator to work in safety.

10. Additional handle. This device allows you to more conveniently hold the tool in the process. The ability to fix the handle in several positions turns the tool into a more convenient and versatile device.

That’s all, and then I propose a more detailed look at the device with an angle grinder and with all the modules listed.

Read more on the website connecting the drill button

Principle of operation and device angle grinder

For all types of grinders, the principle of operation is the same and consists in the following:

When you press the start button, an electric current is supplied to the electric motor and starts to rotate the rotor. A rotating rotor transmits rotational movements to the gear of the rotor shaft, which allows using the large gear of the gearbox to rotate the axis of rotation by 90 degrees. The large gear wheel of the gearbox is rigidly fixed in the gearbox housing with the cutting disc spindle. Therefore, during rotation, the large gear transmits rotational movements to the spindle on which the cutting disc is mounted.

Read more on the website the choice of angle grinder

The angle grinder device consists of an angular grinder housing in which are installed:

1. A collector-type electric motor consisting of a stator and a rotor. The stator consists of two copper pole coils made of copper wire such as PET 155, PETV 2 or PET 200.

2. On the back of the case, the angle grinder contains brush holders with graphite brushes in the amount of 2 pcs. used to rotate the collector of the rotor of the electric motor (by means of brushes, voltage is transmitted to the collector to effect rotation of the rotor).

3. The rotor is located inside the stator and is fixed in the housing by means of a bearing connection. The front bearing is located inside the gear housing. The rear bearing is located near the manifold and mounted directly in the housing plastic. The rotor is made of electrical iron with several grooves for laying the wire component of the winding. As a rule, the step of the winding and the number of grooves determine the speed of its rotation.

4. On the front shaft (in the gear case itself) there is a spiral bevel gear that transmits torque from the electric motor to the large gear of the gearbox. Since the large gear of the gearbox is located relative to the helical bevel gear in a different plane, it turns out that the direction of the output shaft changes by 90 °.

5. The gear housing the angle grinder is usually made of aluminum alloy and has threaded holes for attaching an additional handle. An additional handle makes the angle grinder a more convenient tool during operation.

Read more on the site which angle grinder to choose.

Photo 1. Angle grinder device

The following positions are indicated on photo-1:

1-power cord, 2-power button, 3-additional handle, 4-plastic tool case, 5-brush holders with graphite brushes, 6- motor winding (stator), 7-rotor manifold, 8- rear rotor bearing, 9- rubber seal, 10- protective casing, 11- gear spindle, 12-gear housing.

Photo 2. The appearance of the rotor of an electric motor angle grinder

The following positions are indicated on photo-2:

2. Rotor manifold

4. Rotor housing

6. Gear housing

Photo 3. The design and appearance of the gearbox

The following positions are indicated on photo-3: