Repair and maintenance of electric motors

A motor is a rotating machine mainly composed of a stator and a rotor. It converts electrical energy into mechanical energy through the action of the magnetic field generated in the coil.

These machines are pollution-free, constant speed, high performance (about 75%), high and constant torque, do not require cooling or external ventilation, and in general, they are more effective than combustion equivalents.

They are very important in the electric bicycle industry, so the maintenance and maintenance of the motor is very important.

Maintenance

The maintenance of any machine is very important, because it can ensure its correct operation, prevent certain types of failures, and even extend its service life. It can be divided into preventive and corrective.

Regular preventive maintenance is carried out to verify its operation, and perform procedures (adjustment, lubrication, modification, etc.) according to the workload of the motor and replace the parts recommended by the manufacturer. This procedure is performed according to the activities of the maintenance plan and should interfere with its daily operations as little as possible.

On the other hand, corrective maintenance is carried out as a result of motor failure, so it is random and usually leads to interruption of the production process. It is important to minimize its impact, obtain the main spare parts required for repair, and have the right to perform the task. Staff.

In order to protect the motor, electrical and mechanical parts must be covered because they will continue to be used, so they will wear out and be contaminated by external components.

Daily maintenance of electrical components (windings, brushes, etc.) includes modifying connections, replacing carbon brushes and regular measurements. For this, various instruments are needed, such as megohmmeter, microohmmeter, multimeter, oscilloscope, etc. They allow obtaining values for insulation, continuity, frequency, current, voltage, power, and waveform.

At the same time, mechanical components, such as bearings, shafts, and housings, have a protection plan that includes cleaning the mechanical components, inspecting the base and nuts of the motor, and performing measurements to evaluate the speed and balance of the rotor, the torque applied by the load and temperature.

Preventive maintenance activities

1. Check the engine regularly.

2. Remove dust, oil and dirt deposits in the fan cover to maintain good ventilation and allow the motor to cool down properly.

3. Observe the behavior of the seal.

4. Pay attention to electrical and mechanical connections and fixing bolts.

5. Check the bearing, pay attention to abnormal noise and vibration.

6. When the bearings are worn out, replace them with a tool called an extractor, and then connect the new bearings in cold or hot (oil bath) and lubricate them.

7. When the motor is not energized and there is a long static time, use a megohmmeter to test the insulation resistance.

8. If you need to disassemble the motor and touch its internal parts, you need qualified personnel to use appropriate tools and working methods to intervene.

9. When the coil is dirty, clean the winding with a dielectric solvent and bake it with infrared to remove corrosive substances to obtain better insulation resistance.

10. After thorough maintenance, conduct a startup test to verify its operation.

Corrective maintenance activities

1. The motor does not start: check the grid voltage, fuse, contact, correct connection (star or delta according to the terminal board and load), rotor voltage, brush contact, starting resistor circuit and winding insulation.

2. Excessive current absorbed during operation: check the load, if it is smaller, replace the motor, if this is not the case, check the insulation, ring, brush, resistance circuit and rotor winding as appropriate to repair or rewind.

3. Motor overheating: check the load, clean the grille, ventilation slots, wiring board connections and stator windings.

4. The motor smokes and burns: check the windings and always keep the ventilation circuit clean for maintenance or rewinding if necessary.

Conclusion

The motor is the core component of an electric bicycle, and its components will wear out and degrade according to the workload and the passage of time. Preventive maintenance is to reduce service interruption due to corrective maintenance, so its maintenance is very important.