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The Working Principle of Three-Phase Alternator and Operation Essentials

August 05, 2022
Three-phase alternator by the stator and rotor in operation to generate power to the motor, and then the motor in the operation of the current output, the faster the operation of the current, the faster the generator excited before running, to check the parts and water and electricity oil, while the generator in the running process, always pay attention to the operation and make a record, such as high temperature or noise need to stop immediately to check, the following Dongguan generator rental The manufacturer Yatong Xiaobian give you a detailed introduction.
The working principle of three-phase alternator
Three-phase alternator is usually composed of stator, rotor, end caps, brushes, seat and bearings and other components. Stator by the seat. Stator core, wire wrapped windings, and other structural components to fix these parts. The rotor consists of rotor core, rotor pole, slip ring, fan and shaft and other components.
The three-phase alternator uses the principle of electromagnetic induction, in which a wire cuts a magnetic line to induce an electric potential, to change the mechanical energy of the prime mover into electrical output. Synchronous generator consists of two parts: stator and rotor. The stator is the armature that sends out electricity, and the rotor is the magnetic pole. The stator consists of an armature core, uniformly discharged three-phase windings, and a seat and end cap. The rotor is usually of the hidden pole type, consisting of the excitation winding, core and shaft, guard ring, center ring, etc. The number of poles of the turbine generator is mostly two-pole, but there are also four-pole ones.
Through the bearings, chassis and end caps of the generator stator, rotor connection assembled, so that the rotor can rotate in the stator, through the slip ring into a certain excitation current, so that the rotor becomes a rotating magnetic field, the stator coil to do the movement of cutting magnetic lines of force, thus generating an induced potential, through the terminals, connected to the circuit, it will produce a current.
The operation of the generator essentials
Newly installed generators, before use should measure the insulation resistance of the stator and excitation circuit and absorption ratio, the insulation resistance of the stator shall not be less than 30% of the last measured value, the insulation resistance of the excitation circuit shall not be less than 0.5MΩ, absorption ratio shall not be less than 1.3, and shall make measurement records.
Check the internal combustion engine and generator drive part before operation, should be connected reliably, the output line wire insulation is good, the instrumentation is complete and effective.
Before starting, the resistance value of the excitation varistor should be put on the maximum position, then cut off the main switch of power supply output and engage the neutral ground switch. For units with clutch, start the internal combustion engine for no-load operation first, and then engage the generator after it is normal.
After starting, check the generator in the speed up should be no noise, slip ring and rectifier brush contact is good, no jumping and sparking phenomenon. To run stable, frequency, voltage to the rated value, before supplying power to the outside. Load should gradually increase, three corresponding to maintain a balance.
After the generator begins to run, that all electrical equipment should be considered to have been charged. Generator continuous operation of the highest and lowest allowable voltage value shall not exceed 10% of the rated value, its normal operation of the voltage change range should be within 5% of the rated value, power factor for the rated value, the rated capacity of the generator should remain unchanged.
Generator in the rated frequency value of operation, the range of change shall not exceed 0.5Hz. generator power factor shall not exceed late phase 0.95, with automatic excitation adjustment device, can operate under the conditions of power factor of 1, if necessary, can be allowed to run for a short time in late phase 0.95 ~ 1 range.
Generator operation should always check and confirm that the instrument indication and the normal operation of the parts, and should always adjust the generator load, stator, rotor current shall not exceed the allowable value.
Before stopping the engine should first cut off the main switch of each power supply branch, gradually reduce the load, then cut off the main switch of generator power supply, reset the excitation varistor to the maximum resistance position, so that the voltage drops to the minimum value, then cut off the excitation switch and neutral grounding switch, and finally stop the internal combustion engine operation.