1、 Inspection items and contents of power transformation and distribution equipment

（1） Main items and contents of transformer daily inspection

1. Guizhou electric equipment factory tells you to monitor the voltage and load of transformer through voltmeter and ammeter, and record every two hours according to regulations. The allowable voltage deviation of high voltage side of transformer is ± 7% of rated voltage, and that of low voltage side is ± 10% of rated voltage. When the voltage often exceeds the allowable deviation range, the voltage tap should be changed to adjust the voltage.

2. Listen to the operation sound of the transformer. In addition to the normal and uniform Weng hum, there are abnormal sounds such as burst.

3. Check whether the high and low voltage insulation bushing of transformer is clean, whether there are cracks and discharge traces. If there is dirt, clean it with gasoline or alcohol after power failure.

4. Check whether there is leakage at each sealing part and whether the oil level is normal.

5. Monitor the operating temperature of transformer. During operation, the oil surface temperature rise (temperature rise = upper oil temperature - ambient temperature) shall not exceed 45 ℃.

（2） Maintenance period and content of transformer

1. Transformer maintenance without disassembly

Minor repair period: if the capacity is below 1800kVA and the voltage is 10kV or below, minor repair shall be conducted every 1-2 years.

Minor repair contents:

(1) clean and check the transformer shell, outlet bushing and outlet connector.

② Drain the dirt and water in the oil conservator, add oil if necessary, and check the oil gauge.

③ Check the drain valve and sealing gasket.

④ Measure the coil insulation resistance.

⑤ Measure the grounding resistance.

2. Overhaul of transformer

Overhaul period: overhaul every 5-10 years.

（3） Main items and contents of patrol inspection for low voltage distribution equipment

1. Check the appearance of bus bar and joint, and judge whether the temperature exceeds the allowable value through color change of color change paint.

2. Whether the insulator is clean, whether there are cracks and discharge traces.

3. Whether there are other abnormal phenomena in the cable and its terminal joint.

4. Whether the instrument, integrated protection device and signal indicator of the secondary system work normally.

5. Whether the connection between the equipment shell grounding and the zero connection device is loose or broken.

（4） Maintenance cycle and content of low voltage distribution equipment

1. Maintenance cycle: at least once every half a year.

2.Maintenance content

① Clean and remove dust, and check the shell of low-voltage electrical equipment such as knife switch, circuit breaker, air switch, fuse, contactor, relay, master electrical equipment (button, transfer switch, travel switch, etc.) for damage and insulation aging.

② Check the wear of dynamic and static contacts of the above-mentioned low-voltage electrical equipment, test the contact pressure and overtravel, and clean the particles generated after metal melting on the contact surface to ensure good contact area. When the actual overtravel of the contact is only half of the original, replace the contact.

2、 Inspection and maintenance of motor

1. Inspection before motor starting

In order to ensure the safety of equipment and personnel and make the motor start normally, the following inspection shall be carried out for newly installed or overhauled and long-term used motor before starting:

(1) Check whether the voltage and frequency shown on the motor nameplate are consistent with the power supply used, whether the connection method is correct, and whether the capacity of the power supply matches the capacity and starting method of the motor.

(2) Whether the specification of the wire used is appropriate, whether the wiring is wrong, and whether the connection is firm.

(3) Whether the capacity of switch and contactor is appropriate, whether the contact is good, whether the protection current value of fuse and thermal relay matches the rated current of motor

(4) The manual turning gear shall be uniform, stable and flexible, and the movement shall not exceed the specified value. Check whether the bearing is short of oil, whether the oil quality meets the standard, and reach the specified oil level when adding oil.

(5) Check the transmission device, the transmission belt should not be too tight or too loose, and the connection should be reliable without cracking; the screw and pin connecting the coupling should be complete and tight.

(6) Check whether the motor shell has cracks, whether the grounding is reliable, the foundation screw and end cover bolt shall not be loose, and the safety measures such as protective cover are in good condition.

(7) Check the insulation resistance between windings and between windings and ground. The insulation resistance of motors with rated voltage below 500V is required to be no less than 0.5 megohm. If not, drying treatment shall be carried out.

(8) For irreversible motors, check the correct direction of rotation.

2. Inspection after motor starting

(1) Whether the starting current is normal or not, when the three-phase power supply is balanced, the deviation between any phase of the three-phase current and the three-phase average value shall not exceed 10%.

(2) Whether there is abnormal sound and vibration, whether there is peculiar smell or smoke.

(3) Whether the running current is normal, whether there is overload, whether the motor temperature rise is normal.

3. Contents and methods of daily inspection

Examination site

Inspection items

Inspection contents

Inspection method

4. Annual inspection contents

(1) Disassemble and clean the motor winding, ventilation ditch and wiring board.

(2) Measure the winding insulation resistance and dry it if necessary.

(3) Check the unevenness and deflection of collector ring and commutator, and adjust the brush holder and the distance between them.

(4) Clean the bearing and lubrication system, replace the rolling bearing that is worn beyond the specified value, and hang tin again for the seriously damaged sliding bearing.

(5) Repair the grounding device and measure the grounding resistance.

(6) Adjust the transmission device and replace the seriously worn belt.

3、 Maintenance and lubrication of motor bearing

1. Bearing inspection method

(1) Listening: insert one end of the screw driver or iron bar into the machine with bearing, and the other end with the ear to hear whether there is any special noise. If the intermittent sound is generated, it indicates that there may be impurities in the bearing; if there is a whistling sound, the bearing may have foreign matters