Sensory diagnosis is quick and easy

1. Judgment of abnormal sound of power transformer

Normal operation of transformer, clear and uniform hum.If there is any abnormal sound, judge the cause of the fault point.A buzzing sound of high pitch, overload or overvoltage.

Intermittent violent gurgle, single - phase load increased sharply.There was a jingle of hammering and the threaded screw was loose.There was a crack of applause, and the ground wire broke.

Intermittent wheezing, iron - core grounding disorder.Winding short circuit is slight, issued bursts of crackle.The winding short circuit is more serious, sending out loud roar.

There was a crack in the high pressure casing and a high frequency hiss.High pressure fuse shell flashover, crackle crackle sound.The low - voltage phase wire is grounded and can be heard from far away.

Drop switch tap, poor contact squeak.

2. Use a semiconductor radio to detect partial discharge of electrical equipment

Patrol transformer and distribution equipment, partial discharge is difficult to be found.Carry a pocket radio and tune to no station.Turn up the volume and listen to the sound. The even buzz is normal.

If the sound is irregular, there is a very loud firecrackers, or a very loud squeak, near the partial discharge.Then turn the volume down and approach the device one by one.

Again heard the sound of firecrackers, the equipment under test has a fault, the equipment partial discharge, the launch of high-frequency electromagnetic wave.

3. Use a listening stick to diagnose common motor faults

Use the sound bar to confirm the motor fault.A continuous stir was heard, and the rotor collided with the stator.The winding slows to a hum and the coils collide with the shell.

The speed slows to a whisper and the coil is broken and out of phase.Hiss in the bearing room, bearing oil dried up.The bearing part gurgled and it was concluded that the bearing was damaged.

4. Check the hollow percussion method of the wooden pole body

Patrol check the wooden pole, the pole body around the hammer percussion.To the sound of a good sound, a hollow sound.

5. Check the insulation condition of the generator set bearing with the insulated wire of root stripper

Bearing insulation test during generator set operation.With the root stripping head insulation wire, one end of the wire first ground, the other end touch the rotating shaft, several times touch carefully.

Poor spark insulation, good insulation without spark.

6. Judgment of single-phase grounding fault in neutral ungrounded system

Three-phase voltage who is the largest, the next phase must be faulty.

7. Patrol and inspect the power capacitor

Patrol to check the capacitor, the drum oil leakage temperature rise.Abnormal cuckoo sound, internal discharge fault.

8. Use charge and discharge method to judge the quality of miniature capacitor

Miniature capacitor is good or bad, charge and discharge method is crude judgment.The capacitor is connected to the power supply at both ends and charged for about a minute.Use a root insulated copper wire and short connect two capacitive electrodes.

Sparks are good to shine, no sparks have been damaged.

9. Identify lead battery polarity

Lead battery bipolar, positive and negative signs can not be seen clearly.Polar column color to distinguish, negative gray is dark brown.Pole position on the difference, by the factory sign pole.

The diameters of the poles are different. The positive pole is thicker and the negative pole is thinner.Broken saw blade pole, the harder pole is positive.Pole pole lead into sweet potato, line turn green is positive pole.

Connect the two wires of the pole column and immerse in dilute sulfuric acid solution to produce the negative end of bubbles, without the regular end of bubbles.

10. Scraping method to check the battery single cell battery short circuit

Battery internal short circuit, more in one or two grid.Single cell battery short circuit, commonly used fire scraping inspection.With a thick copper wire, connect to a single cell battery pole,

Hold the other end of the wire in your hand and quickly scratch the other pole.Blue and white sparks appear, the single case detected is good.Red spark is lack of electricity, no spark has short circuit.

11. Check the wiring of the three-phase energy meter with two components with the middle-phase voltage method

Three - phase three - wire watt-hour meter, check the middle - phase voltage.Disconnect the middle phase voltage line under constant load.

Watch the electricity meter running, the disk is turning half slow, the only correct wiring, otherwise the wiring is wrong.

12. Judge whether the inner wire of the microammeter is broken

Microammeter coil on and off, the multimeter can not be measured.After the microammeter terminal, short connect the copper wire, then shake the microammeter, at the same time look at the pointer.

The slow oscillation amplitude is small, the coil in the table is intact.Fast and large swing, the coil in the table is broken.

13. Analyze and judge the fault according to the fuse's fusing condition

Check the fuse's fusing condition and determine the fault in the line.The exposed fuse is completely fused to explode, seriously overload or short circuit.The middle part of fuse has small fracture and long normal overload time.

Compression screw near the break, installation damage is not pressed.

14. According to the color ring logo to identify the resistance

Finished small resistor, color ring nominal resistance value.Color ring the first ring is determined, near the resistance edge ring.The last ring is the deviation, the penultimate ring is a multiple.

The rest of the color ring resistance value ring, resistance value effective number.Color code color represents number, multiple tens to the power of the value.Brown, red, orange, yellow, green, blue, purple, one two three four five six seven,

Grey is zero white and black, gold is one silver is two negative multiples.

15. Identification method of poor quality aluminum core insulated wire

Plastic insulated aluminum core wire, see the core skin to judge the merits.Core wire soft silver white, inferior harder color hair black.

Color color printing factory name, poor quality old no logo.Sheath core contact tight, poor quality sleeve large core loose.

16. Identify incandescent light bulbs

Incandescent bulb stand or fall, see hand model to differentiate.Bubble round bright and clean without sand holes, product logo printed words.The glass wick is not askew, the wire hook tungsten wire is arranged.

Lamp holder installation is not askew, slightly hard pull does not feel loose.

17. Identify the quality of transformer oil

Transformer oil is usually light yellow when viewed from outside.After operation, it is light red, the oil aging color becomes dark, the strength is different, the carbonization is serious and the color becomes black.

Tube filled with oil into the light, good oil transparent fluorescence.No blue-purple reflection, poor diaphaneity foreign matter.Good pressure drying overheated coke odor, severe aging with acid taste.If there is an electric arc in the oil, acetylene will be smelled.

18. Temperature rise of the motor is detected by dripping water

Motor temperature rise dripping measurement, sprinkling a few drops of water on the casing.Only steam without sound, the motor under test did not overheat.The steam hissed and the motor overheated.

19. A simple method for determining the direction of a three-phase motor before installing a rotor

Motor steering prediction, rotor not installed determination method.The copper wire is bent into barrel shape, and the stator inner diameter is fixed.The stator is fixed vertically and the cotton wire bucket is placed in it.

After the drum stops stable, the instant power is switched on, the drum rotates and turns.

20. Four-level discrimination standard for insulation mechanical strength of motor

Motor insulation pros and cons, mechanical strength to measure.Sensory diagnosis finger according to the four standard discrimination.Finger pressing without crack, insulation qualified feel hard.

Small cracks occur on time and the insulation is fragile.Large deformation occurred on time and the insulation has broken down and stopped using.

21. Temperature rise of the motor is measured by hand temperature method

Motor operating temperature, hand temperature to detect.Flick fingers feel hot, the back of the hand flat on the case.Long touch hands turn red, about 50 degrees slightly hot.

The hand can stay two or three seconds, 65 degrees is very hot.It was very hot, seventy-five degrees hot.The touch was unbearable, but eighty-five degrees overheated.

22. Which phase of fuse is judged by the temperature of the insulation part of the melt tube of low-voltage fuse holder

Several fuses are arranged on the low voltage distribution panel.Hand mould melting tube insulation part, hot melt tube melt broken.

23. Hand pull wire method to find the core breaking fault points between flexible wires

Single - core rubber sleeve flexible wire, middle - break core search method.Hold the line with both hands, more than two hundred millimeters apart.At the same time, try to pull it out.

Line diameter suddenly become thin, is the core fault point.

If you would like to know more about electrical automation, or need any electrical automation products,please contact Cherry.We are specialize in PLC,DCS,TSI modules,controller,robot spare parts,converter,I/O module and modulating control system.

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