How to repair your own electric drill

If you have certain skills, repairing an electric drill in a domestic environment is quite simple. There is a fairly large number of various failures of this tool, but the main ones are the following:

  • failure of motor components;
  • brush wear;
  • malfunction of the regulator and reverse element;
  • bearing wear for support;
  • improper clamping of the chuck fixture.
Electric Drill Diagram

Diagram of the device electric drill.

These malfunctions can occur due to improper use of an electric tool or in case defective elements are installed.

The design of the electric drill consists of the following elements:

  • speed regulator;
  • reverse element;
  • brush holder;
  • brush;
  • motor stator;
  • impeller for cooling the electric motor;
  • rotary collector plates;
  • rotor design;
  • winding.

The most common type of breakdown is the wear of the motor brushes. You can replace them with your own hands. In some cases, the replacement brushes can be made without dismantling the tool body.

In some devices, you just need to remove the plugs from the special windows, and then mount the new brushes. However, there are models in which to perform the replacement of brushes you will definitely need to disassemble the body. If the latter are used, then it will be necessary to carefully remove the holders for the brushes, then remove the replaceable elements from them.

Connection diagram of the drill button with reverse

Connection diagram of the drill button with reverse.

Brushes can be purchased at any electrical tool shop. In some cases, an electric drill is sold with an extra pair of brushes.

You should not wait until these elements are izotrutsya to the minimum size. In such cases, the gap may increase between the brush and the collector plates. As a result, high sparking will occur. The collector plates will get very hot, and then move away from the base of the collector. Ultimately, you will need to replace or repair the armature.

Identify the need to replace the brushes can be based on sparking. To do this, look through the slots of the housing for ventilation. Also, to check you can randomly pull the drill in the process.

In some cases, you may need to repair the power cord. This element can be checked with an ohmmeter. To do this, one probe must be connected to the contact of the network cable, the other probe is connected to the cable core. If there is no resistance, then there is a break. In this case, to repair the electric drill, you will need to replace the power cord.

Elements that are needed to perform the repair electric:

  • special pullers;
  • spare parts;
  • ohmmeter;
  • megohmmeter

How to perform diagnostics of an electric motor?

Another fairly common failure is the failure of parts of the electric motor. Anchor or stator breakage can occur for several reasons: incorrect use and poor quality winding wire. Famous manufacturers use expensive winding wires with double insulation protective lacquer, resulting in increased reliability of the motor.

Anchor pattern

Anchor pattern.

In budgetary devices, the quality of wire insulation is not the best. Incorrect use contributes to constant tool overloading. During prolonged work, it will be necessary to take breaks in order to allow the engine to cool down.

It is impossible to rewind the armature or stator without special tools. The experts will be able to repair these devices with their own hands, therefore it is recommended to completely replace the stator or the armature in case such a need arises.

To replace the rotor or the anchor, you need to disassemble the structure, disconnect the wires, brushes, dismount the drive gear, if necessary. After that, the motor is removed together with the bearings for support. At this stage, you can replace the faulty fixture and assemble the structure.

The malfunction of the armature is determined by the presence of a corresponding odor, an increase in the number of sparks. In such cases, the sparks will have a circular motion towards the anchor. During the inspection process, noticeable damaged windings will be visible. However, if the power of the electric motor decreases, and the signs described above will not, then you will need to use devices for measurement - an ohmmeter and a megohmmeter.

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Existing winding damage

Diagram of the percussion mechanism of the drill

Diagram of the percussion mechanism of the drill.

The windings are subjected to only three damage: breakdown on the body, inter-turn and breakage of the winding. To determine the breakdown of the case, you need the megohm meter probes to touch any winding outlet and cable.

If the resistance is more than 500 megohms, then there is no breakdown. It should be borne in mind that all measurements can only be carried out with a megohmmeter, the measurement voltage of which is more than 100 V. By performing measurements with an ordinary multimeter, it will not be possible to determine exactly whether the surf is present or not.

The inter-turn breakdown of an anchor is very difficult to determine, if it was not possible to visually notice it. It is recommended to use a transformer structure for determination, which has an exclusively primary winding and a wire break in the form of a gutter into which an anchor is installed.

The latter will be used together with the core as a secondary winding. It will be necessary to turn the anchor so that the windings are used alternately. Next to the core you need to attach a thin plate of metal. If a short circuit occurs, the plate will rattle, and the winding will become very hot.

Quite often, the closure between the coils appears on the visible parts of the anchor. The coils may be bent. Particles that conduct current can also be located between them. If this is the case, then it will be necessary to exclude the closure data. This can be done by correcting the irregularities of the bob or removing foreign particles. A closure can also be found between the collector plates, which are located nearby.

Drill motor connection diagram

Connection diagram of the motor drill.

To determine the breakage of the armature winding, you will need to connect a milliammeter to its adjacent plates, then slowly scroll the anchor. In serviceable windings, a uniform current will occur, in the broken windings, the current may be absent or it may increase in some places.

Breakage of the windings can be determined by connecting an ohmmeter to the ends of the windings. If there is no resistance, then this means that there is a complete break.

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Repair of the speed control and reverse element

If voltage is present at the input terminals of the power button, and there is no voltage at the output terminals, this means that there are faults in the contacts or elements of the speed controller circuit. To disassemble the button, you will need to slowly connect the clamps of the casing for protection, then remove the buttons from its case.

By inspecting the terminals it is possible to determine their operability.

If the terminals are blackened, they will need to be cleaned from carbon with fine-grained emery paper. Next, the button will need to re-assemble and check for contact. If there are no changes, then the button with the regulator will need to be replaced. The regulator is installed on the substrate and covered with a protective material, so it will not work to repair it. Another malfunction of the button is the abrasion of the working layer under the rheostat slider. In this case, you will need to make a complete replacement of the button.

You can repair this item yourself only if you have the appropriate skills. After disassembling the structure, many parts will fall out of the structure. This can be eliminated only by raising the lid and sketching the placement of contacts and springs.

The device of the reverse element can be located outside the button body. In such cases, it has its own contacts, which can also disappear. The technology of disassembly and assembly in this case will be the same as that of the button.

Drill Chuck Diagram

Scheme drill chuck.

In the process of acquiring the speed controller, you will need to make sure that it is designed for tool power.

Wiring diagram in different designs may vary. The simplest scheme is this: one wire from the power cable is connected to the speed controller. It is important to understand that the speed controller and the reverse device are two different elements, which are often located in different housings.

The only wire that comes out of the speed controller will need to be connected to the beginning of the first winding. In the absence of a reverse element, the end of the first winding must be connected to the brush, while the second brush is connected to the start of the other winding. The end of the winding will lead to the power cord.

Changing the direction of rotation of the rotor will occur in the case when the extreme part of the winding will be connected not to the first, but to the second brush. In this case, the first brush must be connected to the beginning of the second winding.

In the reverse element there will be a similar switch, because the brushes are fastened to the windings.

The design of the speed controller of such a device provides for the connection of a capacitor and two wires to the controller, which come from the socket.

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Repair gearbox and electric drill cartridge with their own hands

If there are extraneous sounds, gnash and jamming of the cartridge, it means that the gearbox is faulty. In this case, the problem may lie in the failure of the gear shift. You will need to inspect all installed gears and bearings. If there are worn splines or damaged teeth on the gears, then you will need to perform a full replacement of these devices.

Bearings need to check for suitability after they are removed from the axis of the armature electric drill. To do this, use a puller. It will take two fingers to hold the inner clip. If uneven slipping clips are detected during the rolling process, the bearing will need to be replaced.

Often you need to perform and replace the drill chuck. The clamping elements of the cartridge are subject to wear, as they get dirt and remnants of building materials. If you need to replace the cartridge, you will need to unscrew the locking screw inside the cartridge, and then unscrew it from the shaft.

Repair the drill is very simple, you only need to identify the faulty element.

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