The rotor repair method is a relatively complex repair technology, and it is difficult for ordinary people to master it. Since the appearance of the hand drill rotor, it has been used by most people. However, after using it for a long time, it is inevitable that there will be failures, so the rotor should be repaired. Next, this article will specifically introduce the repair methods and common faults of the hand drill rotor.

The operation protection and fault cleaning of the electric hand drill The single-phase electric drill motor adopts the series excitation motor. The series motor for single-phase electric drill has the advantages of small size, high speed, low starting current, and convenient use. Its defects include radio interference, simple sparks and noise.

Single-phase electric drill motor structure Single-phase electric drill series motor consists of two parts: stator and armature (rotor). The stator consists of an iron core, a magnetic pole coil, a casing and a brush. The armature is composed of iron core, armature winding, commutator and so on.

Common faults and repairs of single-phase electric drill motors:

The failure of the single-phase electric drill motor is related to factors such as load, protection and planning and production quality. Because of the high speed of the series motor for single-phase electric drills, it brings certain difficulties to the repair of the motor from the aspects of materials and technology. Therefore, the repair of the single-phase electric drill motor should be carried out according to the original design data as much as possible.

The failure of the armature winding and its repair methods are as follows:

The armature winding is the most important part of the single-phase electric drill motor, and the transformation of electromechanical energy is realized through the armature winding. Because the single-phase electric drill motor rotates at a high speed, the current in the armature winding changes direction sharply, and the armature is in the center of the motor, so it is difficult to dissipate heat and the temperature rise is high. Therefore, when the single-phase electric drill is powered, the motor has large sparks, low speed, weak rolling, and when the possible faults such as brushes, brush holders, bearings, etc. are eliminated, most of the faults occur in the armature windings.

Armature winding open circuit

The open circuit of the armature winding of the hand drill is most likely to occur at the welding of the armature winding and the commutator, and may also occur in the slot. The latter is because the motor has a short circuit or a ground fault, and the current is too large and the coil is blown.

Check method:

Remove the armature from the hand drill, and use a multimeter to measure the resistance between the two commutator segments of the commutator phase order | j, the resistance value of the hand drill of different standards is different. Take a 6mm hand drill as an example, its resistance is about 3 to 5ω. Normally, the resistance between two adjacent commutator segments of the armature winding is the same. When the measured resistance between two pieces is several times larger than the resistance between other pieces, it means that the winding connected to the commutator segment has an open circuit.

Electric drill rotor repair method:

The armature winding open circuit fault point mostly occurs in the welding of the winding and the commutator. One is fake welding, and the other is mildew. If the disconnection point is at the welding point between the winding and the commutator segment, it is only necessary to re-weld it; if the winding is mildewed, it is necessary to strip off the binding wire adjacent to the commutator, and most of the mildewed breaks occur here. Find the broken end, solder it with tin, and do insulation treatment, then use the original wire of the same quality to bind the armature lead, and then penetrate the insulating paint and dry it, and then it can be re-installed and used; if the disconnection point is in the slot , you need to remove and rewind. In emergency use, the two commutator segments connected to the winding open-circuit coil can also be short-circuited with wires, which can be used continuously, so that the use of hand drills has little effect.

Armature winding short circuit The short circuit of the armature winding is mainly due to the short circuit between the turns of the armature winding or the mutual connection of the turns between the adjacent coils due to insulation damage. When measuring the resistance between the commutator segments with a multimeter, it is found that the resistance between the segments is too small, which may be a short circuit in some windings.

To check the method, first weld the two wire ends of any commutator segment, connect the low-voltage DC power supply to the armature winding, and then use a voltmeter to measure the inter-chip voltage between two adjacent commutator segments in turn. The voltage value between the two commutators is small or zero, which indicates that the windings connected to the two commutator segments are short-circuited. However, it should be noted that the insulation damage between the commutator segments will also constitute the above phenomenon, and the difference should be carefully checked.

If the short-circuit point appears between the commutator segments, this is because the brushes are worn for a long time, and the ground copper scraps and graphite powder accumulate between the commutator segments to form a partial short circuit. The accumulation between the slices is cleaned up to restore the insulation between the commutator slices.

After understanding the repair methods and common faults of the hand drill rotor, once various faults appear in the future, we will know how to carry out the corresponding hand drill rotor repair, so as to achieve higher work efficiency and prolong the service life of this equipment.