Reasons and Treatment Methods of Diesel Generators No Power Generation Part 2

About the reasons and treatment methods of diesel generators no power generation, now we will continue the previous article. 

1. The stator winding is insulated, short circuit.

(1) The stator winding is tidy. For long-term deactivated or overhaul diesel generators, the insulation resistance should be measured before investing in operation, and unqualified people are not allowed to enter. The moisture diesel generator should dry treatment.

(2) The winding itself is defective or improper inspection process, resulting in winding insulation breakdown or mechanical damage. Insulation materials should be selected according to the prescribed insulation level, and the laying windings and immersion paint should be strictly carried out in strict accordance with the requirements.

(3) Winding overheat. After the insulation is overheated, the insulation performance is reduced, sometimes in the high temperature will soon cause insulation breakdown. A daily inspection should be strengthened to prevent overheating of the generator from being overheated and the winding insulation is damaged.

(4) Insulation aging. The general generator runs more than 15 to 20 years, and its winding is insulated, the electrical performance changes, and even makes an insulating breakdown. To do a good job of repair and preventive testing of generators, if the insulation is not qualified, the defective winding insulation or replace the windings should be replaced to extend the life of the generator.

(5) Internal generator enters metal foreign matter, do not leave metal objects, parts or tools to the stator after maintenance generators; tighten the tie lines of the rotor, fasten the end parts, to do not occur due to centrifugal force Surprote.

(6) Excessive voltage breakdown: 1) The line suffers from lightning strikes, and lightning protection is not perfect. Lightning protection facilities should be improved. 2) Mistakement, such as in the air, the diesel generator voltage is high. The diesel generator should be subtracted in strict accordance with the operation procedure to prevent errors. 3) The internal overvoltage inside the diesel generator includes operating overvoltage, arc grounding overvoltage and resonant overvoltage, etc., should strengthen the winding insulation preventive test, timely discovery and eliminate the defects in the stator winding insulation.

2. Stator core slack.

Due to improper manufacturing, the core is not tight. If it is a whole core, a small diesel generator, two pieces of iron plates that are smaller than the inner diameter of the stator winding end, and the iron core is tightened. After the original shape is restored, the core is primarily clamping the bolt. If a partial iron core is relaxed, the silicon steel sheet can be painted between the relaxation sheet, and then the rigid insulation is placed in the slack portion.

3. Short circuit of the iron chip.

(1) Iron core laxes, when the diesel generator is operated, the core is vibrated and damaged; the iron chip is insulated from insulation or the iron core is partially overheating, and the insulation is aging, according to the method in the original plan.

(2) Mechanical damage when there is burrs or overhaul when the edges of the iron chip. Apply a thin file to remove the burr, repair the injury, clean the surface, and apply a layer of silicon steel.

(3) Skinning or copper particles are short of iron cores, should be scraped or bleed from metal welding joints to handle the surface.

(4) The arc short circuit occurs, and may cause the iron core short circuit, and the burn portion should be cleared by the chisel to handle the surface.

4. Diesel generators lose remnants, can not power when starting.

(1) After the stop, the remanence is often lost, and it is due to the material used by the exciting machine magnetic pole, and there is less magnetic. When the excitation winding is no current, the magnetic field disappears when there is no current, and there is a battery, which is charged before the diesel power is generated.

(2) The magnetic pole of the diesel generator is lost, and the DC current (very short) of the total current current is picked up (time is very short), which can restore enough residual magnetic.

5. Excitation of the automatic excitation device temperature is too high.

(1) The reactor coil is partially short-circuited, and the reactor should be checked.

(2) The air gap of the reactor magnetic circuit is too large, and the magnetic circuit air gap should be adjusted.

6. After the diesel generator is started, the voltage can not rise.

(1) Excitation loops, so that the voltage can not rise. It should be checked whether the excitation circuit has no wire, whether it is good.

(2) Remove the magnetic disappearance, if the exciting machine voltage meter does not have an instruction to explain the loss of magnetism, it should be magnetized by the exciting machine.

(3) The magnetic field polarity of the excitation machine should be replaced with the positive and negative connection lines.

(4) In some tests in diesel generator, the magnetic field coil is misused in reverse direct flow, resulting in removing magnetic disappearance or reverse, and should be re-magnetized.

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