Causes and elimination of difficulties in starting of shaded pole motors

Causes of starting difficulties and their elimination

(1) Shaded pole coil is broken or welded. Most of the shaded pole coils are made of bare copper bars or bare copper into a rectangular shape and welded at the ring mouth, such as improper operation when bending, the copper tube will swell or crack, or due to poor welding of the ring mouth, virtual welding, false welding, after use After a period of time, the original hidden danger was expanded to cause the short circuit ring to be de-soldered and cracked. The short-circuit ring was not effective and the motor was difficult to start. The solution is to repair the symptom. If it is found to be virtual welding or false welding, re-weld the ring mouth. If the short-circuit ring is broken and cannot be repaired, replace the short-circuit ring with the original specifications.

(2) The load is too large or the driven equipment is faulty. In case of overload operation, the load should be adjusted to a moderate level. If the driven machinery is faulty and the resistance is high, the mechanical equipment should be checked and repaired in time.

(3) The motor bearing is worn heavily, the rotation is not flexible or stuck, and the lubricating grease is dried or deteriorated, which causes difficulty in starting. After careful inspection, if you find that the bearing is damaged, you should choose a new bearing of the same specification and replace it. The installation should be correct. If the lubricating oil dries up, the original bearing will not dry and the grease will be cleaned with steam. The new bearing will be cleaned and dried. Apply a clean and proper amount of lubricating grease inside and outside the bearing cover.

(4) The cast aluminum cage bar and the end ring of the rotor are broken, the broken bar, or the welding place of the copper cage bar and the copper end ring is cracked or welded, which causes difficulty in starting. The cracks of broken bars or end rings and the cracks of copper end rings and cage bars were detected through inspection, and repaired and replaced as appropriate.

(5) The main winding is broken. When the main winding is open, the power supply cannot be connected and the motor cannot be started. The main winding wire may be in the lead section and may be in the turn, mainly the winding, improper wiring, improper connection of the motor during use. The solution is to use the meter resistance file to detect, if the winding is not open, then find the specific open circuit, connect the broken wire and weld it firmly, and wrap it with insulation.

(6) The main winding is short-circuited or wrongly connected. For example, the main winding of a salient pole motor is short-circuited. Because it is a multi-turn concentrated winding, it is wound with a thinner enameled wire. When the winding is too large, the paint will be scratched, or the overload will often run. The film is peeled off due to overheating and aging, causing a short circuit between turns. In addition to the above two reasons for distributed slot winding, the paint film between turns turns into a short circuit during the wire embedding process. The solution is to measure the short circuit first, and depending on the specific location and severity of the short circuit, take local bandage or replace the winding to repair.

(7) Improper assembly of the motor after overhaul. For example, the stator and the rotor core have a paint film on the inner surface, which sometimes makes it difficult to start, or difficult to start at a certain location. The solution is to disassemble the motor, remove the paint film, align the rotor during assembly, ensure that the rotor iron is aligned, ensure concentricity, and make the air gap uniform, so that the motor can start smoothly.