Drill and cordless screwdriver is an irreplaceable device in repair work. This electric tool is powered by an AC outlet or a battery. The battery-powered drill requires the purchase of a charging device.
Often, manufacturers produce such units in a set.
Chargers for drills differ in cost, features of work and their principles. Despite the general functionality, screwdriver chargers differ in their internal arrangement.
According to the method of converting the voltage of the electrical network, chargers are divided into:
They appeared initially. The structure of this apparatus consists of:
The main disadvantage of such a device is its high weight and large size. This is due to the fact that such dimensions increase the power of the unit in direct proportion. In this regard, there is a direct relationship between size and power. Small size transformer chargers provide little power, which affects the full charge time of the drill.
They work according to a different principle.
They use the conversion of the input voltage into an electric high-frequency charging current of the screwdriver. This method of operation makes it possible to use small transformers that work with high power ratings. Inverter chargers, being much smaller in size, produce significant amounts of electric current for charging. The time taken to recharge the battery is reduced to 1 hour or less.
The popularity of these units is explained by the low price.
For domestic use, a unit with less functionality is suitable. The charger must meet the requirement for fast current load and charge rate.
Note. To start charging the screwdriver, you need to create a charging voltage for the power supply screwdriver at the output greater than the battery indicator of the device.
The operation of analog chargers with a power supply is extremely simple.
The use of such a device is carried out as a stabilizer. In practice, it is not at all important what type of battery is used.
Cordless screwdrivers are popular with those who plan to use them only for household work. A very important point is knowledge of the features of repairing units in case of breakdown. A power supply of this type can be assembled with your own hands.
The screwdriver charging circuits are soldered on a universal board. The best device for dissipating heat is a 20 cm² copper radiator.
Note. The stabilizer is used in the work on the principle of compensation. Excess energy is removed in the form of heat.
The output transformer provides the generation of an alternating voltage for charging the screwdriver to decrease from 220 V to 20 V. The calculation of the power of the transformer takes place according to the voltage current at the output of the charger. The diode bridge organizes the rectification of the alternating electric current, after which it becomes pulsating. Such a nuance, however, has a negative impact on the operation of the circuits. The ripple is smoothed by a filter capacitor.
The KR 142EN microcircuit is used as a stabilizer. To create a voltage of 12 V, you need to use a microcircuit with an index of 8B. also resistors are used. These types of units operate without a process automation mode. To control the charge, you can assemble a simple circuit on the VT1 transistor.
The circuit has a VD2 diode. When the charge voltage is reached, the charging indicator of the screwdriver goes out.
Modern systems are equipped with a switch. This allows the voltage to be disconnected at the end of the charging process. When you buy a cheap drill, you get a regular charger in the package.
In this regard, cases of breakdown of the unit occur much more often than with expensive models. That is why the knowledge of assembling the charger will be useful to every owner of inexpensive screwdrivers. A self-assembled charger can last much longer than one purchased in a store. To select the value of the screwdriver battery, it will be necessary to adjust the operation of the stabilizer and transformer by trial and error.
The circuit of such a charger is simple.
The complete set includes a power supply unit and a charger. The circuit of the screwdriver charging unit has a standard package: transformer, diode bridge, capacitor filter, rectifier. Outputs 18 V.
It is controlled by means of a small board, which is the size of a matchbox. Such devices do not have a heat sink system, which affects the service life.
This unit becomes unusable very quickly.
To charge the drill without battery, follow these guidelines:
Depending on the charging current, it can dissipate up to 10 watts. The radiator power should have an area of 30 - 40 cm².
Important! Analog units have one significant drawback - a long period of full charge. This moment is not critical for home use screwdrivers.
Professional use requires the use of tools that are ready to work for a long period without recharging.
The high functionality determines the corresponding cost of the devices, they cannot be cheap. The complete set of such units includes 2 batteries.
The impulse circuit of the screwdriver charging unit has an intelligent control circuit, which in turn provides one hundred percent charging in just 1 hour. Among the positive qualities of these devices, it should be noted their small size, high charge current, the presence of a protection system. Given these points, the circuit of such a charger is rather complicated.
Those who cannot afford such devices can build a charger on their own. Thus, you can save 2 times.
Chargers for NiCad cordless screwdrivers, equipped with a third signaling contact. The assembly diagram of the unit on the MAX713 is the most commonly used. The output voltage is 25 V at constant current.
Charging has several intelligent functions. After checking the voltage level, the charge acceleration mode is started, which makes it possible to prevent the memory effect. A full charge is completed after 1.5 hours. Such a scheme makes it possible to select the type of battery and the charging force.
Situations when the drill is working and the charger is broken are not uncommon. There are plenty of ways to solve the problem, but due to the fact that the parts are toxic, not everyone wants to deal with them. To continue using the screwdriver, you need to connect
. To continue working with the screwdriver, connect the external charging unit of the screwdriver.
4V batteries in Chinese models allow the use of a car battery. Another option for solving the problem would be a transformer with an output voltage of 15-17 V. All the necessary parts are quite affordable. You will need a diode bridge and a thermostat. There is no need to purchase a stabilizer.
In order to assemble the drill battery charging with your own hands, you need to study the tool diagram and the characteristics of the parts. To work you need a soldering iron and the ability to handle it. If the power supply of a professional tool fails, it can be converted to a network one.
Posted By: Work Style |04, Nov 2020
Posted By: Work Style |10, Nov 2020
Posted By: Work Style |08, Nov 2020
Posted By: Work Style |04, Nov 2020
Posted By: Work Style |10, Nov 2020