Today it is impossible to find a person who would not know about the existence of an electric drill. Many had to use this tool. But how this indispensable thing in the household is arranged, not everyone knows.
Types of drills.
Inside the drill case there is an electric motor, its cooling system, a gearbox, and a drill speed regulator. About the work of the regulator of revolutions of the drill it is worthwhile to talk a little more. All parts wear during operation; the drill button is particularly susceptible to this process. And with it the system of adjustment of turns is directly connected.
Purpose of the speed controller
Device of smooth start-up of a drill.
The regulator of turns of a modern electric drill settles down in the button of inclusion of the device. To achieve such small dimensions allows microfilm technology, on which it is assembled. All parts and the board itself, on which these parts are located, are small in size. The main part of the regulator is a triac. The principle of its operation is to change the moment of the circuit and turn on the triac. It happens like this:
- After the button is turned on, the triac receives a sinusoidal voltage on its control electrode.
- The triac opens and the current begins to flow through the load.
With a larger amplitude of the control voltage, the triac is switched on earlier. The amplitude is controlled by a variable resistor, which is connected to the trigger of the drill. The button connection scheme in different models may be slightly different. Just do not confuse the speed controller with a reverse control device. These are completely different things. Sometimes they can be placed in different buildings. The speed controller can provide for the connection of a capacitor and both wires from the outlet.Back to table of contents
Using a drill as a machine
Figure 1. A typical scheme of the regulator drill speed.
The hand drill may be used outside the box. On its basis, make a variety of machines: drilling, grinding, circular and others. In such machines, the function of speed control is very important. In most household drills, the speed is controlled by the start button of the device. The harder it is pressed, the higher the revolutions. But they are recorded only at the maximum values. This in most cases can be a significant drawback.
You can get out of this situation by self-production of a remote version of the speed controller. As a regulator it is possible to use a dimmer, which is usually used to adjust the illumination. The regulator circuit is quite simple and is shown in Fig. 1. To make it, you need to connect wires of different lengths to the outlet. The long wire with the other end joins the plug. The rest is going according to the scheme. It is recommended to use an additional automatic switch that will turn off the device in case of an accident.
Homemade speed control is ready. You can perform a test run. If it works normally, you can place it in a suitable size box and fix it on the frame of the future machine in a convenient place.Back to table of contents
Repair buttons with speed control
Figure 2. Scheme of the speed controller for a microdrill.
Repairing a button is a rather complicated process that requires certain skills. When opening the case, some parts may just fall out and get lost. Therefore, the work needs caution. In case of malfunctions, the triac usually fails. This item is very cheap. Disassembly and repair take place in the following order:
- Disassemble the body of the button.
- Rinse and clean the inside.
- To remove a payment from the scheme which is on it.
- Vypayat burnt part.
- Solder a new part.
To disassemble the case is very simple. It is necessary to bend the sides and remove the cover from the clamps. Everything must be done carefully and carefully so as not to lose 2 springs that can jump out. It is recommended to clean and wipe the inside with alcohol. The clamps in the form of copper squares extend from the slots, the board is easily removed. A burnt triac is usually clearly visible. It remains to evaporate it and solder in its place a new part. Assembly of the regulator is performed in the reverse order.Back to table of contents
Microdrill speed controller
Diagram of the device of the impact drill.
Many have to drill printed radio cards. Usually, a microdrill made of various parts with its own hands is used for such work. For such tools, you can also make the speed control. Schemes for making can be found many. The similar scheme of a regulator of turns is presented on fig. 2. All items are quite affordable. The LM317 chip is installed on the radiator to protect it from overheating. Capacitors are normal, electrolytic, 16 V.
Diodes brand 1N4007 can be replaced with any others that withstand a current of 1 A. The AL307 LED can be replaced with any other. The entire circuit is assembled on a glass fiber laminate board. Resistor R5 can be a wire or other power, 2 watts.
The power supply for a voltage of 12 V. With a higher voltage, it is necessary to change the capacitors in the circuit. The finished product usually starts working immediately. The engine speed is regulated by a resistor P1. Load sensitivity is set by resistor P2.
The drill speed regulator is a necessary device, especially when the drill is used as the basis for the manufacture of a homemade machine.
In modern devices, this device is placed in the start button. Self-made device can be placed in any suitable case. There are a lot of manufacturing schemes.