Angle Grinder Doesn’t Gain Speed ​​Cause

Any power tool may fail over time. Usually this is due to a violation of the rules of its operation. The angle grinder is no exception. If you have such a nuisance, do not panic and immediately call the wizard, because in most cases you can fix the malfunction yourself.

Angle Grinder Doesn't Gain Speed ​​Cause

Figure 1. Angle grinder device.

To do this, you need to know the basics of electrical engineering and a little understanding of the design of grinding machines. Next, we will discuss how to repair a do-it-yourself angle grinder.

Device and principle of operation angle grinder

To understand how the angle grinder works, you first need to familiarize yourself with the principle of operation of this tool. With the help of electricity, the engine is operated, which transmits rotational motion to the shaft through a special gear. A grinding or cutting wheel is fixed at its end.

The high quality of work carried out with an angle grinder will depend on the number of revolutions of the cutting blade in 1 min. In a professional power tool, this value can reach 10,000 rpm or more.

First of all, if the angle grinder breaks, it should be disassembled and carefully cleaned, in most cases the tool starts to work.

For different manufacturers, the layout of the angle grinder may differ slightly, but the main parts of all models are the same (Fig. 1):

  • Two-piece housing
  • electric motor of a certain power;
  • gearbox;
  • electrical part.

The case is made of shockproof plastic. Its main task is to keep all the components in place and transfer the forces exerted by the operator to the cutting element.

The electric motor drives the drive gear of the gearbox, which rotates the driven gear, on the axis of which the disk is located. The gearbox consists of gears through which the axis of rotation is rotated 90 °. Thanks to the use of gears of various diameters, the optimum speed of rotation of the cutting blade is achieved.

Main malfunctions angle grinder and their elimination

Before repairing the angle grinder, it is necessary to prepare tools and materials that may be needed during the repair work:

  • tester;
  • screwdriver;
  • spanners;
  • knife;
  • tweezers;
  • sandpaper;
  • insulating tape;
  • solidol;
  • alcohol;
  • rags.

The main principle that you must adhere to when repairing any power tool is that you should move from simple to complex, that is, the sequence of repair work should first eliminate the elementary malfunctions.

If the angle grinder fails, the first thing you need to remember is the circumstances in which the breakdown occurred. This will help with a high probability to establish the cause of the failure, which will allow for successful repair of the angle grinder.

Video: Angle Grinder Doesn’t Gain Speed ​​Cause


The most common breakdowns of an angle grinder are open circuit or short-circuited turns in the stator or armature windings.

The most vulnerable point of the angle grinder is the electrical part, which breakdowns occur most often. It can burn from excessive load of the tool during work, from getting water inside the device, from power surges, etc.

The mechanical part does not like abnormal operating modes, poor or untimely care of bearings and gear elements of the gearbox, and the tool falling to the floor. Therefore, before you repair the angle grinder, you must carefully clean its body and trigger. If this does not help, then the angle grinder will have to be disassembled for further inspection and repair.

Very often a situation arises when the angle grinder suddenly stops working. The first thing to do in this case is to disconnect the device from the power source and manually rotate the drive. If it does not crank or cranks very tight, then you need to completely disassemble the tool and inspect its mechanical part. If the disk scrolls easily, it means that power is not supplied to the motor brushes. This may be due to a failure of the power cord or the Start button.

First of all, you need to inspect the power cable for integrity. Very often it is bent at the place of its entrance to the case the angular grinder. To eliminate such a breakdown, it is necessary to remove the cover from the handle of the device, after which the tester will ring 2 wires. If a break is found in any place, it is better to replace the cable with a new one.

It is better not to twist, because at the place of twisting the wire will bend again after a while.

Anchor device angle grinder.

With the handle cover open, you can immediately see the condition of the brushes on the armature collector. If they are worn out, they should be replaced. To do this, open the 2 windows of the brush holder and, bending the spring, replace. New brushes should be similar to old ones.

Carbon deposits may form on collector plates, making it difficult to evenly press the brushes. In this case, soot should be removed. To do this, take the tweezers and wrap cotton wool on it. After that, remove the brushes, wipe them and the collector with alcohol, and then set the brushes back.

If after these operations the angle grinder still does not start, this means that the cause of the malfunction lies in the start button, which should be repaired. For repair, you need to disassemble the trigger. At the same time, it is recommended to mark the removable elements, which will save you from improper reassembly. The serviceability of the button must be checked by the tester. If it turns out that it is faulty, replace it with a new one.

Sometimes a situation arises when an abnormal noise is heard during operation of the angle grinder. To eliminate such a problem, open the gearbox by unscrewing the 4 fixing screws. If the gear is worn, replace it with a new one.

If the speed of the tool has decreased and strong sparking is visible from under the brush, then the insulation of the armature is broken. It is necessary to dismantle the old anchor and replace it with a new one. Such repairs are not always cost-effective, since the anchor is quite expensive.

Another vulnerability of an angle grinder is bearings. This is due to the fact that the tool often has to work in dust, and a high speed suggests their rapid wear. Bearing wear is not a terrible breakdown, because it changes easily enough. The main thing is to replace them on time, because otherwise you may have more serious problems.

How to extend the life of an angle grinder

  • use the tool only for its intended purpose;
  • during operation, do not neglect the main technical characteristics of the grinder indicated by the manufacturer;
  • do not block the power tool;
  • timely lubricate the mechanical elements of the device, while only high-quality lubricants should be used;
  • carry out maintenance according to the flow charts for the equipment and fully.

If you will follow all the rules and recommendations when working with an angle grinder, then you can be sure that such a power tool will last much longer than its warranty period.

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