Generator Light Towers Extend The Life Of The Generator

First, the structure and principles

1, structure

Synchronous Generator Light Towers are mainly composed of stator, rotor and other components.

The stator part includes stator core, stator winding, base;

The rotor part includes the rotor core, the excitation winding and the slip ring (the hidden pole rotor also has the hoop, the center ring, the salient pole rotor has the magnetic pole, the yoke, the rotor bracket)

Other components include brush units, end caps, bearings and fans.

 2, the working principle

Synchronous Generator Light Towers operate according to the principle of electromagnetic induction, which through the rotor magnetic field and the relative movement of the stator winding, the mechanical energy into electrical energy.

When the rotor in the external force, the rotor magnetic field and the stator conductor for relative movement, that is, the conductor cutting magnetic field lines, so in the conductor to produce induced electromotive force, the direction can be determined according to the right hand rule.

Since the position of the rotor pole causes the conductor to cut the magnetic field lines in the vertical direction, the induced electromotive force in the stator winding is maximized at this time.

When the magnetic pole turns 90 degrees. Magnetic pole into a horizontal position, the conductor does not cut the magnetic field lines, the induced electromotive force is zero. The rotor and then turn 90 degrees, the timing stator winding and cut the magnetic field lines in the vertical direction, so that the induced electromotive force to the maximum, but the opposite direction and the former.

When the rotor is turned 90 degrees, the induced electromotive force becomes zero again. As the rotor rotates for a week, the induced electromotive force of the stator windings also changes positively and negatively. If the rotor continuously rotates continuously, a periodically changing alternating electromotive force is induced in the stator windings.

Second, the fault diagnosis and elimination methods

 1, generator overheating

(1) the generator does not operate according to the specified technical conditions, such as the stator voltage is too high, the iron loss increases; the load current is too large, the stator winding copper loss increases;

The frequency is too low, so that the cooling fan speed slows down, affecting the generator cooling; power factor is too low, so that the rotor excitation current increases, resulting in rotor heat. Should check whether the instructions to monitor the instrument is normal. If it is not normal, to make the necessary adjustments and treatment, so that the generator in accordance with the provisions of the technical conditions.

(2) generator three-phase load current imbalance, overload of a phase winding will overheat;

If the difference between the three-phase current exceeds 10% of the rated current, that is, the imbalance of the current phase, the three-phase current imbalance will produce negative sequence magnetic field, thereby increasing the loss, causing the magnetic pole winding and hoop and other components of heat. Should adjust the three-phase load, so that each phase current as far as possible to maintain balance.

(3) the air duct is blocked dust, poor ventilation, resulting in difficulties in generating heaters. Should clear the wind tunnel dust, grease, so that the air duct unimpeded.

(4) the inlet temperature is too high or the water temperature is too high, the cooler has a clogging phenomenon. Reduce the intake or inlet temperature to remove clogging in the cooler. Before the fault is excluded, limit the generator load to reduce the generator temperature.

(5) bearing plus grease too much or too little, should be required to add grease, usually bearing room 1/2 to 1/3 (low speed take the upper limit, the high speed of the lower limit), and not more than 70% of the bearing room is appropriate.

(6) bearing wear. If the wear is not serious, so that the bearing overheating; if the wear and tear, it is possible to make the stator and rotor friction, resulting in stator and rotor to avoid overheating. Should check whether the bearing noise, if found stator and rotor friction, should immediately shut down to repair or replace the bearing.

(7) stator core insulation damage, causing short circuit between the chip, resulting in increased core eddy current loss and heat, serious damage to the stator windings. Should be immediately shut down for overhaul.

(8) stator winding parallel wire fracture, so that the current of other wires increased and heat. Should be immediately shut down for overhaul.

 2, the generator neutral to the ground there is an abnormal voltage

(1) Under normal circumstances, due to the impact of high harmonics or manufacturing processes and other causes of the magnetic gap under the uneven, magnetic potential ranging from the very low voltage, if the voltage in a few volts, there will be no danger , Do not have to deal with.

(2) generator winding short circuit or ground insulation, resulting in deterioration of electrical equipment and Generator Light Towers performance, easy to heat, should be timely maintenance, so as not to expand the accident.

(3) no load when the neutral line to no voltage, and there is a load voltage, is due to three-phase imbalance caused by the three-phase load should be adjusted to make its basic balance.

3, the generator current is too large

(1) the load is too large, should reduce the load.

(2) transmission line phase short circuit or ground fault, should line maintenance, troubleshooting can be restored to normal.

 4, the generator terminal voltage is too high

(1) The voltage of the generator grid connected to the grid is too high and the voltage of the generator should be reduced.

(2) excitation device failure caused by over-excitation, should promptly check the excitation device.

5, lack of power

As the excitation device voltage source excitation compensation is insufficient, can not provide the armature reaction required excitation current, the generator terminal voltage is lower than the grid voltage, can not send the rated reactive power, should take the following measures:

(1) in the generator and the excitation between the reactor to connect a three-phase voltage regulator to improve the generator terminal voltage, so that the magnetic field of the excitation device gradually increased.

(2) to change the excitation device voltage magnetic flux potential and the generator terminal voltage phase, so that the synthesis of the total magnetic flux increases, the reactor can be connected to each end of each winding thousands of euros, 10W resistance.

(3) to reduce the resistance of the varistor, the generator excitation current increases.

6, stator winding insulation breakdown, short circuit

(1) stator winding damp. For long-term deactivation or over a long period of time maintenance of the generator, put into operation before the measurement of insulation resistance, substandard are not allowed to run. Damped generator to be dried.

(2) winding itself or improper maintenance process, resulting in winding insulation breakdown or mechanical damage. Should be in accordance with the provisions of the insulation level selection of insulating materials, embedded winding and dipping drying, etc. to be strictly in accordance with the requirements of the process.

(3) winding overheating. Insulation overheating will reduce insulation performance, sometimes at high temperatures will soon cause insulation breakdown. Should strengthen the daily inspection inspection, to prevent the various parts of the generator overheating damage to the winding insulation.

(4) insulation aging. General generator running 15 to 20 years, the winding insulation aging, electrical performance changes, and even insulation breakdown. To do the generator repair and preventive test, if found insulation failure, should be replaced with defective winding insulation or replacement winding, in order to extend the life of the generator.

(5) inside the generator into the metal foreign body, after the maintenance of the generator will not metal objects, parts or tools left into the stator bore; tighten the rotor tie line, tighten the end parts, so as not to occur due to centrifugal force And loose.

(6) too large voltage breakdown:

①, the line suffered lightning, and lightning protection is not perfect. Should improve the lightning protection facilities.

②, misuse, such as in the no-load, the generator voltage rise too high. Should be strictly in accordance with operating procedures for the generator to boost, to prevent misuse.

③, the generator over-voltage, including the operation of over-voltage, arc grounding over-voltage and resonant over-voltage, etc., should strengthen the winding insulation preventive test, timely detection and elimination of stator winding insulation defects.