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Essential basic knowledge for motor use

Date:2024-05-17   Author:XINDA MOTOR

1. Inspection

1. Carefully check the nameplate data to confirm that the motor model meets the usage requirements. 2. Use a 500V megger to measure the insulation resistance of the motor winding to the shell. The insulation resistance should be greater than 0.5MΩ.

2. Installation

1. The motor is generally installed in a clean, dry place indoors. The surrounding must be well ventilated. The maximum temperature of the ambient air does not exceed 40°C and the minimum temperature is not lower than -15°C. Strong thermal radiation should be prevented.

2. Motor control appliances should have phase loss protection and overload thermal protection devices. YA series increased safety motors must select appropriate overload thermal protection devices based on the nameplate tE time and starting current ratio IA/IN.

3. Connect the power cord according to the wiring diagram. The terminal connection must be tight. Motors with lead-out cables and wires can be directly connected to the power cord, and the joints must be insulated and sealed.

4. When the power cord, phase sequence and electric thick terminal mark are connected correspondingly, the motor rotates clockwise when viewed from the shaft extension end. When you need to change the direction of rotation, just change the wiring positions of the two power cords.

5. Variable-stage multi-speed asynchronous motors such as the YD series use the method of switching lead wires to control changes in rotational speed. In order to ensure the reliability of multi-speed motor operation, attention should be paid to the design and operation of the control device when switching from high speed to low speed. , the neutral point of the 2Y wiring must be disconnected when cutting off the power supply to avoid causing a short circuit in the power supply when the low-speed winding is connected. During the process of switching from high speed to low speed, the power supply to the low speed winding must be turned on after the motor stops to reduce the impact on the motor and load. When switching the speed, pay attention to the steering of the motor.

6. The motor can be equipped with a coupling, and the gears, belts and loads are mechanically connected. 2-pole motors above 4kw and 4-pole motors above 30kw should not be driven by belts. The second shaft extension of the double-axis extension can only use a coupling. transmission. The tightness of the coupling, pulley shaft hole and motor shaft should be appropriate, and it is strictly forbidden to use a heavy hammer during installation. When coupling transmission is used, the center line of the motor shaft and the center line of the load mechanical shaft should coincide with a gap of 1 to 3 mm in the axial direction of the coupling. When a belt is used to transmit room motion, the center line of the motor shaft should be parallel to the center line of the load mechanical shaft, and the center line of the belt and the center line of the shaft should be perpendicular to each other.

3. Grounding

The motor must be reliably grounded. The grounding method and grounding resistance should comply with electrical safety management regulations such as the "Grounding Design Specifications for Industrial and Civilian Electric Power Installations" and "Factory Electricity Design Technical Specifications". The grounding resistance should be less than 4Ω.

4. Start

1. After closing the circuit breaker, the motor should start immediately, reach normal speed and run smoothly. Otherwise, cut off the power supply immediately, check and eliminate the fault.

2. After starting, pay attention to the motor transmission device, load machinery, voltmeter and ammeter. If there are any abnormalities, stop the machine immediately.

3. The motor should generally not be started more than 4 times without load, and should not be started more than 2 times after running to a hot state. Otherwise, the motor will be easily burned out.

4. Reasonably select the starting method according to the grid capacity, load size and motor power. Larger power motors should be started using the triangle method or the voltage reduction method.

5. Operation

1. The deviation between the power supply voltage and the rated voltage shall not exceed ±5%, and the unbalance of the three-phase voltage shall not exceed 1.5%.

2. The operating current of the motor shall not exceed the rated current on the nameplate, and the three-phase current imbalance shall not exceed 80%. Otherwise, the motor will heat up or even burn out.

3. Use a thermometer to measure the surface temperature of the motor casing should not exceed 80°C, and the temperature of the bearing should not exceed 95°C.

4. The motor should always be kept clean, dry, and well ventilated, and the air inlet and outlet must be kept clear of frost. 5. If the motor smokes, violently vibrates, abnormal sounds, special smells, or the speed drops significantly during operation; the load equipment fails; if a person gets an electric shock, the power should be cut off immediately.

 6. Bearing lubrication

1. The motor bearings should be well lubricated. Generally, after running for 3000-5000 hours, the motor should be shut down for maintenance to replenish or replace the grease. The grease grade is ZL-3 lithium grease.

2. Before using a motor that has been stored or out of service for more than two years, the lubrication condition of the bearings should be checked, and the grease should be replenished or replaced if necessary.

3. Sealed bearings are used for motors with a center height of 132 and below. Motors with a center height of 160 and above generally use unsealed bearings. The sealed bearings do not need to be replaced with grease during use of the motor. Unsealed bearings should be replaced with clean grease regularly. The appropriate amount of grease should be added. Generally, 1/3-1/2 of the cavity between the inner and outer rings of the bearing is filled. For motors with grease injection devices, just add 3-4 times with a lubricating gun. Open the bearing cover before adding. For the discharge hole or cover at the bottom, plug the discharge hole or install the cover after the motor has been running for 20 minutes. When disassembling or installing the discharge hole plug or cover, the power should be cut off and the machine should be shut down.

 7. Transportation and storage

During transportation, the motor should not be subject to moisture, the shaft extension should not be bumped, and the parts should not be damaged, etc. The storage place should be kept clean, dry, ventilated, free of corrosive gases, and free from sudden changes in ambient temperature.