If the light does not come on, it may mean the following:
Posted: Mon Feb 17, 2025 5:32 am
Makita, tool free
In one of the Makita models, smoke started to appear during operation , which is a correct sign of a burnt rotor or stator. To determine the causes, the author carried out a complete disassembly of the angle grinder , which allowed for a good external inspection of the units suspected of being faulty. If there were no signs of smoke on the rotor, then several places of burnt electrical insulating varnish are clearly visible on the stator .
Checking contacts with a light bulb
If there is no tester, you can get out of the situation with a simple 12-volt light bulb. The power can be any, optimally 30-40 W. The voltage from the 12-volt battery must be supplied to the plug of the grinder, inserting the uae telegram data bulb into the break of one wire. With a working anchor, if you rotate the spindle manually, the light should burn without changing brightness. If the glow changes, this is a sure sign of an interturn short circuit.
The brushes may be stuck in the idle position. The retaining spring has been triggered.
Power supply circuit break.
A short circuit or break in the stator winding has occurred.
There are other diagnostic methods, but they require more sophisticated equipment that is not usually used at home. An experienced technician will be able to pinpoint the fault with a high degree of accuracy using a "punch" or a simple transformer with a split toroidal core and one primary winding.
Continuity tester
If the visual inspection does not give unambiguous results, it is recommended to continue the inspection with a multimeter. Having set the mode switch to the ohmmeter position (200 Ohm range), it is necessary to "ring" two adjacent anchor lamellas with two probes. If the resistance on all turns is the same, this means that the windings are in good condition. If on some pairs the tester shows a different resistance or a break in the circuit. There is a malfunction in this coil.
In one of the Makita models, smoke started to appear during operation , which is a correct sign of a burnt rotor or stator. To determine the causes, the author carried out a complete disassembly of the angle grinder , which allowed for a good external inspection of the units suspected of being faulty. If there were no signs of smoke on the rotor, then several places of burnt electrical insulating varnish are clearly visible on the stator .
Checking contacts with a light bulb
If there is no tester, you can get out of the situation with a simple 12-volt light bulb. The power can be any, optimally 30-40 W. The voltage from the 12-volt battery must be supplied to the plug of the grinder, inserting the uae telegram data bulb into the break of one wire. With a working anchor, if you rotate the spindle manually, the light should burn without changing brightness. If the glow changes, this is a sure sign of an interturn short circuit.
The brushes may be stuck in the idle position. The retaining spring has been triggered.
Power supply circuit break.
A short circuit or break in the stator winding has occurred.
There are other diagnostic methods, but they require more sophisticated equipment that is not usually used at home. An experienced technician will be able to pinpoint the fault with a high degree of accuracy using a "punch" or a simple transformer with a split toroidal core and one primary winding.
Continuity tester
If the visual inspection does not give unambiguous results, it is recommended to continue the inspection with a multimeter. Having set the mode switch to the ohmmeter position (200 Ohm range), it is necessary to "ring" two adjacent anchor lamellas with two probes. If the resistance on all turns is the same, this means that the windings are in good condition. If on some pairs the tester shows a different resistance or a break in the circuit. There is a malfunction in this coil.