The drill does not work at low revs

The drill does not work at low revs

Sometimes a construction tool becomes a victim of malfunctions at the most inopportune moment. To correctly repair the electric drill, you need to imagine how the tool is arranged. The features of the electric drill device are described below and recommendations are given what to do in case of the most common malfunctions.

Typical Drill Design

To understand how to fix a drill, you need to be able to determine in which of the blocks a malfunction occurs. In the electric drill device, mechanical and electrical components are released. Both of them are mounted inside the case. On the shaft is a cartridge into which the drill is placed.

Electrical part

The electrical circuit of the drill is sometimes placed in the instructions for the device. A wiring diagram may be required for communication problems between the components. Usually this part of the device consists of:

  • Drill speed regulator;an electric motor using alternating current (includes a rotor and a stator);
  • Reverse gear;
  • Start buttons
  • Contact brushes installed in the holder;
  • Capacitor;
  • Network connection cord.

Mechanical part

The components of this part include a bearing combination and a gearbox that reduces the rotation speed when transferring it from the engine to the shaft. An impact drill includes other elements: two types of pistons and a ram.

It should be noted! Soviet-made drills differed from the current ones in some design features (they did not have a reverse and hammer drilling option).

Types of malfunctions of the electrical and mechanical parts of the drill

The most common problems with the electrical component are cases where the drill sparks on the brushes due to their significant grinding or wear. A device with very worn brushes will not turn on at all. A sign of problems with the engine is the absence of signs of its inclusion (sound, vibration, etc.). With a speed-controlled drill, reverse and speed control may stop functioning.

Mechanical failures. Failure of the bearing or gear mechanism, shaft failure. They are manifested by buzz, periodic device stops, slow rotation. Sometimes there are problems with the cartridge: difficulties in disconnecting the drill, twisting the cartridge relative to the shaft.

Algorithm for finding and eliminating breakdowns of the electrical part

If you intend to repair the drill, you must adhere to a certain algorithm, starting with the simplest and most common problems and filtering them out as you diagnose:

  1. If the device does not turn on, open the case and examine the cable contacts with a multimeter. Connection is made to the male connector and the opposite terminal, after which the cable bends 2-4 times in length. If the contact is unstable or absent, the wire breaks inside the insulation coating. If a kink is located near the edge, the wire can be cut and reconnected. If not, it must be replaced.
  2. If there is no problem with the cord, diagnose the switch by connecting the multimeter to the terminals. Sparking and oxidation of contacts indicate problems. The switch must be disassembled, cleaned of dust, treat the contacts with emery.
  3. Inspect the communicators between the switch and the brushes. Then the brushes themselves. They should be well pressed by springs to the lamellas of the rotor. If the brushes are worn, they should be replaced. If clogged, remove dust and erase.
  4. Check for a short circuit between the winding contacts and the housing and measure the resistance. There should be approximately the same indicator on all windings. If it differs by more than 5%, it must be rewound.

Important! Do not check wire contacts with voltage on. This is fraught with a shock or a short circuit situation.

DIY drill repair

The following are measures to repair an electric drill with your own hands for the most common malfunctions.

Motor fault

This is a very common problem that occurs with high loads on the mechanism (long work without respite, excessive load with a jammed drill) or defective windings. A common symptom is the smell of burnt. For fidelity, you can check the resistance of the windings with an ohmmeter and a tester. The case of the device must be opened, remove the brushes and remove the motor with bearings. The element that caused the problem is deleted and replaced with a new one or sent to the workshop for repair.

Checking the electrical components

Test the voltage at the switch terminals. If it is not, the body of the button is removed and contacts are checked. Processed with alcohol and emery, tested again, if there is no signal. Change the button. You can also check the connection diagram of the drill button and check for contact with the wire. In its absence, the wire is soldered.

Gear or cartridge malfunctions

Problems with the gearbox are indicated by grinding sounds or a jamming cartridge. Gears are checked, if there is wear or deformation of the teeth, they are replaced. Bearings are checked by rolling the shaft. With a tight course, they must first be lubricated.

The need to replace the cartridge is signaled by difficulties with removing the drill. The cartridge is removed by first unscrewing the screw or knocking it out by tapping the end (if it is fixed with a cone).

Power button, soft start and speed control

The trigger and the regulator begin to jam due to problems with the chip. The regulator, mounted in the button-switch, is removed together with it, installed separately. Removed, after separating the contacts, and replaced with a working one.

The button is also easier to replace, but you can try to repair it yourself. The knife pulls the tabs, removes the lid. Dust the inside with a cotton swab soaked in alcohol. They take out the microcircuit and sequentially ring the parts. Defective replace. Often, dusting is sufficient to restore normal operation.

The reverse does not work, or the drill does not turn to the right

If the drill does not turn left or right, you must check the state of the switch button. If necessary, replace it or clean it from the inside. The reverse is called on the left and on the right, if at least once the ringing failed, it is recommended to replace the button.

Connecting a drill to a cable without a button

The button is removed, a couple of ends of the stator windings are combined and connected to the brush. Another pair of combined ends and wires of the other brush are connected to the cores of the button cable. Joints are covered with insulation.

Small and high revolutions

In case of difficulties with low revs, it is necessary to check the regulatory mechanism and soft start. With the ability to work exclusively at low speeds and heating the body, the brushes and the collector are also inspected.

The drill does not turn on

Checked button for drill, capacitor, power cable and contacts. If all these elements are in normal condition, press a button and examine for signs of engine problems. Wireless devices can help recharge the battery.

The drill is cracking but not spinning

If the motor removed from the housing does not work, the gearbox must be replaced. If it works, check the windings (starter and rotor) and brushes.

Rotor Repair

A visual inspection reveals deformed turns, molten wiring, and a damaged manifold. You can repair the anchor in the workshop or replace it with a new one. Before pulling it is separated from the gearbox and stator. The winding can be rewound independently.

Stator Repair

A multimeter test is carried out at a resistance of 200 ohms. The windings should have the same performance. If damaged, rewind.

Replacing Anchor Bearings

Bearing removal is carried out with a special tool. In its absence, the rotor is hung on metal plates so that it is lower, and the bearing is higher than the plates, and a wooden spoon is tapped on the shaft. Install a new quarter-inch socket head bearing. To drive an element into place, tap on it with a hammer.

If the drill battery does not charge

The battery is disassembled, the resistance on the primary winding is checked (absence indicates a broken circuit), as well as the windings and the fuse. If there are breakdowns, the transformer must be replaced. Also check the components of the board, if necessary, change to new ones.

Support plate flies

Plastic plates are more stable, if possible you should buy just that. The rubber can be fixed by putting it on the bolt with the working side to the hat and placing a large washer on top. Then the design is tightened with a nut.

Impact Replacement

Remove the retaining ring and gear from the shaft, then rest the shaft against the switch ball. A clutch with teeth is removed from the gear housing. Lubricating smudges and other contaminants are removed from the shaft and housing. The tool itself also needs to be dusted inside. Then put new elements and process the lubricant.

Drill Chuck Repair

The cartridges are not the same in size and outer diameter. When the new cartridge has the last parameter larger than the previous one, additional nozzles cannot be used. This must be taken into account. However, key and keyless chucks of different sizes (but with the same diameter) can be replaced one by another. If contamination is clogged in the cartridge, it can be cleaned by disassembling. They put it on a vice with their fists up, put a plate of metal and hit it hard with a hammer, then the sleeve drops below. They remove the washer and fists, check the condition of all components, replace the damaged ones, and remove dirt.

Essential tool

When planning the repair procedure for a drill with your own hands, you will need to prepare the following tools:

  • Screwdriver with nozzles;
  • Vise;
  • Bearing puller;
  • Keys for nuts and butts;
  • Sandpaper for grinding;
  • Ohmmeter and megohmmeter;
  • Pliers;
  • Calipers.

In order to competently make an independent repair of a drill, you need to imagine the device of its electrical and mechanical filling. In this case, most malfunctions can be eliminated at home.