Speed controller for angle grinder: connection diagram of the dimmer to the angle grinder
If the angle grinder is not equipped with a turn regulator, can you install it yourself?Most angle grinders (angle grinder), in common parlance, have a speed controller.
Speed regulator is located on the body of the angle grinder
Consideration of the various adjustments must begin with an analysis of the electrical circuit diagram of the angle grinder.
The simplest representation of the electrical circuit diagram of a grinder
advanced models automatically maintain the speed regardless of load, but more common are tools with manual adjustment of disk speed. While a drill or electric electric screwdriver uses a trigger-type regulator, this principle of regulation is not possible on an angle grinder. First. the peculiarities of the tool imply a different grip when working. Secondly, adjustment during work is not allowed, so the RPM value is set when the motor is off.
Why do you need to adjust the speed of the angle grinder disc??
- When cutting metal of different thicknesses, the quality of work strongly depends on the speed of the disc.If you are cutting hard and thick material you should use the maximum RPM. When machining thin tinplate or soft metal (such as aluminum), high speeds will lead to melting of the edge or rapid blurring of the working surface of the disc;
- Cutting and cutting stone and tile at high speed can be dangerous.In addition, a disc that rotates at high RPM knocks out small particles of material, making the cut surface appear sloppy. And different speeds are selected for different kinds of stone. Some minerals are machined at high RPM;
- Grinding and polishing are in principle impossible without speed control.Wrong RPM settings can damage the surface, especially if it is a car paint finish or material with a low melting point;
- The use of discs of different diameters automatically requires a regulator. When changing from Ø 115 mm to Ø 230 mm the rotational speed has to be practically halved. And it is almost unreal to hold an angle grinder with a 230 mm disc rotating at 10 000 rpm in your hands;
- Stone and concrete surfaces can be polished at different speeds, depending on the type of crown used. And the torque should not decrease as the rpm decreases;
- When using diamond discs it is necessary to reduce the number of revolutions, because their surface quickly fails due to overheating.Of course if your angle grinder only works as a cutter for pipes, angles and profiles there is no need for a speed regulator. And in case of universal and versatile use of angle grinder it is vital.
Typical speed controller circuit diagram
This is what the speed regulator board looks like assembled
A motor rpm controller is not just a variable resistor that reduces the voltage. The electronic control of amperage value is necessary, otherwise the power and, accordingly, the torque will proportionally decrease with the fall of rpm. In the end, there will come a critically low value of voltage, when at the slightest resistance of the disk, the electric motor simply can not turn the shaft.Therefore, even the simplest regulator must be calculated and executed in the form of an elaborate circuit.
And more advanced (and therefore expensive) models are equipped with regulators based on an integrated circuit.
Integral regulator circuit. (the most advanced version)
If we consider the electrical scheme of the angle grinder in principle, it consists of a speed regulator and a soft starter module. Power tools equipped with advanced electronic systems are significantly more expensive than their simple counterparts. Therefore, not every home craftsman is able to purchase such a model. And without these electronic blocks there will only be the winding of the electric motor and the trigger.
The reliability of modern electronic components of the angle grinder exceeds the life of the motor windings, so you should not be afraid of purchasing power tools, equipped with such devices. Only the price of the product can be a limiter. Not only that, users of inexpensive models without a regulator sooner or later come to install it themselves. The unit can be purchased ready-made or make it yourself.
Making a speed controller with your own hands
Attempts to adapt a regular dimmer to adjust the brightness of the lamp will not do anything. First, 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. Therefore, you have to mount a separate circuit, and figure out how to place it in the tool body.
IMPORTANT! If you do not have skills to work with electric circuits. it is better to buy a ready-made factory controller, or angle grinder with this function.
The simplest thyristor speed controller is easy to make yourself. You need five radio elements, which are sold at any flea market.
Wiring Diagram for a Thyristor Speed Controller for your Tool
Compact design allows you to place the circuit in the housing of the angle grinder without compromising ergonomics and reliability. However, this circuit does not allow for torque to be maintained when the rpm drops. Option is suitable for reducing the speed when cutting thin sheet metal, polishing works, 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 uses chip KR1182PM1, or its foreign analogue.
Circuit diagram of the speed control using the chip KR1182PM1
This circuitry controls the current at all speeds and minimizes the loss of torque at lower speeds. In addition, this circuit is more considerate to the motor, prolonging its life.
The question of how to make the tool rotation control arises when it is stationary. For example, when using an angle grinder as a circular saw. In this case, the regulator is equipped with a connection point (circuit breaker or socket), and the speed is adjusted remotely.
Diagram of connection of the dimmer
The connection diagram of the dimmer is similar to that of the switch. The dimmer, like the switch, is installed in series with the load. Not only that, this device can be put in the same place where there was an ordinary switch. Before you connect the dimmer instead of the switch, you must disconnect the AC power, disconnect the mains cables from the switch terminals and in its place put the dimmer, because its installation dimensions match the dimensions of the switch.
When connecting the dimmer to the electric network, you must take into account that it must be included in the gap designated by the letter L phase wire, but not the neutral wire with the letter N.
How to connect the regulator to the angle grinder
No special knowledge is needed to connect the home-built power regulator, and any home handyman can do the job. Module is installed in the gap of one wire. which supplies the angle grinder. That is, one wire is left intact and the regulator is soldered in the gap of the second.
In the same way you can connect and factory-made power controller for about 150, which is often purchased by craftsmen in China.
If there is very little space in the angle grinder, the regulator can be placed on the outside of the instrument. as shown in the following photo.
Also, the regulator can be placed in the socket and use it to reduce the speed not only the angle grinder, but also other electrical devices (drills, lathes, milling machines or wood lathes, etc.), and other electrical equipment.д.). This is done as follows.
The regulator is connected as described above. at the break of one of the wires of the power cable.
The following pictures show what the finished socket will look like, having a built-in speed controller for the angle grinder, which can also be used for other electrical appliances.
Instead of a junction box, you can use any plastic housing the right size. You can also make the box yourself by gluing pieces of plastic with a glue gun.
Angle grinder, or grinder. often in the household is simply necessary to perform work on metal. In addition, it can be used to clean both wooden and stone materials. It is difficult to imagine doing industrial work without an angle grinder. This is the kind of tool that will suit both the professional in his work, and the amateur in household chores.
When performing work with your own hands, it is important that the power tool has a soft starter. This is especially true if you often have to work and the mains can’t handle the voltage of the tool.
Angle grinder speed controller. after converting an angle grinder to a circular saw
Budget versions of angle grinders. angle grinder. have a number of disadvantages :
- The power tool does not have the option of a soft, gentle start. This can lead to power outages, because the angle grinder in the first seconds after turning on consumes a lot of electricity. There is also a high probability of motor damage and tool breakage after the soft start, and not the soft start, but the sharp, jerky start.
- In power tools, especially simple Chinese, there is no speed regulator (by adjusting the speed can provide long work of the tool without load on it).
Therefore, when choosing a tool, it is very important to pay attention to such parameters as speed regulation and availability of a soft start. In addition, when choosing an angle grinder should pay attention to the power. Here the main indicator is the amount of work to be done.
If the work is not large-scale and not frequent at the household level, then fit an electric tool with an adjustment of 125 mm and a power of between 600-900 watts.
For heavy-duty industrial work, you should use an angle grinder with about twice the power. In addition to the technical features, safety is another key factor. angle grinder must be safe. What it means? First, as has already been said, the presence of a soft start, which prevents power surges during inclusion. Automatic fuses are needed for an emergency stop in the event of a system malfunction. Fuses act as a regulator when the wheel jams. Provides protection against dust. It is necessary for frequent use of the angle grinder so that dust does not accumulate in the tool.
Heat dissipation function is important. The heat sink protects against overheating. During operation, especially if the operation is continuous, the machine housing is exposed to a lot of heat, so that overheating does not occur and heat dissipation is necessary. When overloaded, the angle grinder stops. this occurs during heating, approaching 200 o C. Well, the balance of the disk serves to reduce the unpleasant vibration and runout tools at work, especially affected by this old worn discs. It is very important to pay attention and pay attention to safety when choosing a tool and when working with it.
When choosing a tool, it is worth noting that there are angle grinder with one and two handles. Here you should rely solely on the convenience. Two-handed models are likely to be more comfortable to hold, but such tools are heavier in weight, one-handed models also have to hold with two hands, but such angle grinder is smaller in size and weight.
The leader in the market of power tools is Bosch. The tools from this company have all the features you need, from convenience to safety. Another plus of Bossh instruments is that there is good ventilation.
Connecting the dimmer
All the variety of dimmers that can be found on the market, divided into two main groups. rotary and pushbutton. Rotary dimmers have a rotary knob that can be used to increase or decrease the brightness of the light. Electronic push-button dimmers are different in that they are controlled by touch buttons.
Electronic push-button type dimmers have much more features than simple rotary control switches. Dimmers can be connected to several points in the chain and control its work from different points. When you connect an electronic dimmer, it is possible to regulate the degree of illumination with a remote control.
When choosing an adjustable switch, many are interested in the question of how to connect the dimmer to the mains. There is nothing complicated about connecting a dimmer. A dimmer plugs into the light power supply, just like a normal light switch.
The simplest rotary dimmer has only two terminals, which are easy to connect. But even if you don’t follow the polarity rule, the dimmer will still work. Once connected, you can dim the lights by turning the dimmer switch.
What is the principle of operation of a modern dimmer? Most people know from school physics that you can dim the lights using a rheostat, which changes the resistance value in the circuit. But it does not reduce power consumption. On the contrary, the power consumption increases due to the heat released, which simply escapes into the air. Therefore, the use of rheostats in the home is absolutely not justified.
Electronic dimmers work on a different principle. The main elements of a modern dimmer are a semiconductor dynistor and triac, or, as they are also called, dyad and triac.
These symmetrical semiconductors are capable of carrying a certain amount of current in both directions. Smooth regulation of the voltage that is applied to the lamp, due to the so-called “phase cutoff”.
The power of a dimmer depends on the amount of current a triac is capable of carrying. When choosing a dimmer you must determine the load or the total power of the light bulbs.
Dimmer’s wattage must be slightly greater than the load. For example, if you have three lamps of 100 W each, the total power of all lamps will be 300 W. In that case, to ensure reliable operation, it is better to choose a 500W dimmer.
Advantages of light dimmers in the home
Light dimmers have many advantages over their single-pole counterparts.
- Environmentally friendly: reduces your monthly electric bill by 4-9%;
- allows you to create an atmosphere in the room that fits whatever is going on at the moment, such as children playing or you watching a movie;
- bulbs are used longer with dimmers: the light is dimmed, which will save you at least 25%;
- fluorescent bulbs that are connected to this device will give a softer, cooler color scheme.
Tips for buying the right dimmer: make sure you buy a device that is rated for the total wattage of the light fixture. For example, a light over a kitchen table with 10 100-watt bulbs is too much for a standard 600-watt dimmer.
Rotary models of such a device look like standard switches that slide up or down to control the lights.
They have their own on and off button, so you can turn the light on at the level you want.
Dimmers for ceiling fans
If you are going to connect a dimmer to control a ceiling fan, do not install a standard one, because the fan will burn out and significantly shorten its life. Here are some typical types of adjustable switches that can be installed with ceiling fans:
- fully variable fan speed. used to control paddle fans or chimney sweeps;
- Quiet 3-speed plus. no fan motor noise;
- Quiet 7-speed plus. no fan motor hum;
- control of four ceiling fans with one module for each.
How to make a soft start and speed control for an angle grinder
All budget options 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 power tool into the mains, and at startup you have watched the light bulb drop, which is also plugged into this mains.
This phenomenon occurs because the powerful electric motors at the start-up huge currents are consumed, through which the voltage sags. It can break the tool itself, especially a Chinese-made tool with unreliable windings that can one day burn out during start-up.
That is, a soft start system protects both the mains and the tool. Besides there is a big kick or jolt when you start the tool and of course this would not happen with a soft start system.
Secondly, there is no speed regulator that will allow the tool to work for a long time without overloading it.
The diagram below is from an industrial model:
It is implemented by the manufacturer in expensive appliances.
Not only “angle grinder”, but, in principle, any devices such as drills, milling machines and lathes can be connected to the scheme. But taking into account that the tool must have exactly a collector motor.
It doesn’t work with asynchronous motors. You need a frequency converter.
So it is necessary to make a printed circuit board and start assembling.
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.
Such a triac was not available in the store and had to buy a BTA28. It’s a bit more powerful than the one in the schematic. In general, for motors with power up to 1 kW you can use any triac with voltage not lower than 600 V and current from 10-12 A. But it’s better to have some reserve and to take triacs of 20A, they cost a penny anyway.
The triac will be heated during its operation, so you need to put a heat sink on it.
To avoid the possibility of the motor drawing currents much higher than the maximum current of the triac, which might burn out, remember that the circuit has a soft start and the starting currents can be ignored.
Everyone is probably familiar with the phenomenon of self-induction. This effect occurs when the circuit to which the inductive load is connected is open.
Paano magkabit ng Variable speed Control sa isang angle grinder
It is the same in this circuit. When the power to the motor is suddenly cut off, the inductive current from the motor can burn out the triac. And the snubber circuit dampens the self-induction.
The resistor in this circuit has a resistance of 47 to 68 ohms and a power of 1 to 2 watts. 400 V film capacitor. Self-induction as a side effect in this circuit.
The R2 resistor provides quenching for the low voltage control circuit.
The circuit itself is in some way both a load and a stabilizing link. It is not necessary 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 outputs of the operational amplifier is within normal limits.
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 has no components for speed control. This is on purpose, because in any case the regulator needs to be wired.
Regulator adjustment is done with 100 kOhm multi-turn trimmer resistor.
And the main adjustment is with the resistor R5. It is worth saying that this kind of circuit will not allow adjustment from zero, only from 30 to 100%.
If you need a more powerful regulator, you can assemble it according to the following diagram:
This circuit allows you to regulate the power practically from zero, but for the “angle grinder” it makes no sense.
First, the scheme must be checked for efficiency by connecting a light bulb as a load of 40-60 W 220 V.
If all is well, after disconnecting from the mains, you should immediately check the triac by touch. it should be cold.
Next, the circuit board is connected to the “angle grinder” and the machine is started.
If everything works well. the “angle grinder” starts smoothly, and the RPM is regulated. then it’s time to start testing under load.
How to change the rotation of the angle grinder motor
Electrical component of the angle grinder
During the whole period of its existence, the appearance of the tool has remained virtually unchanged. angle grinder has an elongated body, in which the electric drive and gearbox are installed. A handle is fastened on the side surface of the tool to hold the tool in the working position, and a protective cover is attached to the body of the tool to protect the handyman.
angle grinder, like any tool, can malfunction during operation. In most cases the simple repair of working equipment, its electrical component is required to eliminate the breakdowns.
In order to make repairs, you need to know not only the structure of the mechanical part, but also the wiring diagram of the tool. In order to make a quality repair, you should study the principle of operation of the angle grinder. The electrical diagram of the angle grinder includes the following design elements:
- electric brushes;
- Start and lock button;
- power cable with a plug for connection to the domestic mains.
Each of the components is designed to perform certain functions in the electrical circuit, and the malfunction of any of them leads to a shutdown of the device. For example, the armature is a rotating element of the electrical circuit. It provides the transmission of rotational motion to the grinding disc. In order for the tool to function properly, the armature must rotate at high speed. The higher the speed of rotation of this design element, the higher the power of the device.
Speed regulator and soft start for angle grinder
Both are essential for safe and convenient operation of the power tool.
What is a speed regulator and what is it for
This device is designed to control the power of an electric motor. It can be used to adjust the speed of the shaft. The numbers on the adjustment wheel indicate how to change the speed of the blade.
Not all angle grinders have a speed regulator.
angle grinder with speed regulator: examples in the photo
The lack of a regulator severely limits the use of the sander. Disc speed affects the quality of the angle grinder and is dependent on the thickness and hardness of the material to be grinded.
If the speed is not regulated, the revolutions are constantly kept at the maximum. This mode is only suitable for hard and thick materials, such as angle, pipe or profiles. Reasons why the presence of a regulator is necessary:
- Thin metal or soft wood requires a slower speed. Otherwise the metal edge will melt, the working surface of the disk will wash out, and the wood will blacken due to high temperature.
- For cutting minerals you need to adjust the speed. Most wood-based materials break off in small pieces at high speeds and create an uneven cut surface.
- You don’t need the highest speed for polishing cars, otherwise the paint finish will be ruined.
- To change from a smaller to a larger diameter disc, you have to reduce the speed. It is practically impossible to hold an angle grinder with a large disc rotating at high speed.
- Diamond discs must not be overheated so as not to damage the surface. To do this, lower the speed.
Operations that can be performed with the shredder
The shredder is a multifunctional tool. The leading mechanism is an electric motor, which through the reduction gear transmits motion to the shaft with the changeable nozzle installed on it. A general view of the device is shown in the photo below.
There are models on the market that differ in power and design:
Angle grinder (grinder) FT-1318
Professional large grinding machine 230 mm Stern AG230B
Powerful devices are powered from three-phase voltage of 380 V, and household devices are powered from a single-phase network of 220 V. There are also low power battery models.
Angle grinder (angle grinder) can be made of different materials as follows basic types of work:
Angle grinder is designed to work with such materials:
Grinding machines are widely used in both domestic and industrial applications. This is due to their wide functionality due to the following factors:
- A good choice of different attachments from different materials perform different operations;
- The possibility of fixing the use of special fasteners;
- Some models have additional handles and several speed modes.
In this case, keep in mind that only special blades are used for each material.
The specifics of operation of the angle grinder
The tool is distinguished by its increased functionality. It can be used for cleaning surfaces. It is necessary to equip the angle grinder with special steel rods and sandpaper petals. such a wheel will act as a cleaner.
- for grinding. a concentric nozzle with Velcro is screwed onto the tool. the abrasive is attached to the last one. Immediately before starting work, the function of the connection is checked;
- for grinding with abrasive wheels. the last component must be used extremely carefully. Overexertion can cause the abrasive to break.
By installing special cutting discs, the angle grinder can also be used for concrete grinding. Due to its versatility tool enjoys wide demand for the implementation of any front of work.
The electric motor structure and principle of operation
The principle of operation of an electric motor is based on the interaction of a conductor with a current in a magnetic field.The magnetic field is created by the stator.
The central element in the construction of a direct current motor is the permanent magnet, while for alternating current it is the field winding. The rotor (armature) has its own winding to which a voltage is applied by means of a brush-collector assembly. The interaction of the magnetic fields causes the rotor to rotate.
Features of dimmers for LEDs
As well as for fluorescent lamps, to connect the LED lamp requires a special dimmer. And for LED tapes and LED-lamps different regulators are produced.
To regulate the LED strip are available dimmers designed for direct current and voltage of 12 V. They have two contacts each for input and output: “” and “-“. Connect the input to the power supply, observing the polarity.
Further depends on the type of LED strip:
- monochrome. The tape is connected directly to the dimmer, observing the polarity;
- RGB or RGBW tape. Connect the controller to the dimmer, then connect the strip to it.
There are controllers with built-in dimmers that are controlled by a remote control.
Instructions for use
The main rule when operating an angle grinder with a homemade speed regulator. observance of the work mode and rest. The fact is that a motor running at a “regulated” voltage gets especially hot. When grinding at reduced speeds, it is important to take frequent breaks so that the collector windings do not burn out.
Also, it is highly recommended not to turn on the tool if the speed regulator is set to minimum. reduced voltage is not enough to crank the rotor, the collector lamellae will remain in short circuit mode, the windings will begin to overheat. Turn the variable resistor to maximum, then turn on the angle grinder and reduce the speed to the desired value.
Observing the correct order of switching on and adjusting will allow you to operate the angle grinder indefinitely.
In addition, it should be understood that the RPM adjustment on the angle grinder is on the principle of the water faucet. The device does not increase the speed, it can only reduce it. It follows from this that if the maximum rated speed is 3000 rpm, the angle grinder will work in a range lower than the maximum speed when the RPM controller is connected.
Attention! If the angle grinder already has electronic circuitry, e.g. a speed regulator, then the thyristor controller will not work. The internal circuits of the appliance simply will not turn on.
Equipping the angle grinder with a motor speed control circuit, will increase the efficiency of using the device. and expands its functional range. This will also save the technological resource of the grinder and increase its service life.