First, the impact of processing machine tools on tool accuracy. Effect of machine tool accuracy on tool accuracy When making any tool, the accuracy of the machine tool is the key to determining tool accuracy. Slender rod tools are no exception. The influence of the support block on the tool accuracy The support block equipped with this machine is mainly used for machining slender rod-shaped tools. Its position can be adjusted in both horizontal and vertical directions, and it can be positioned according to actual conditions. If the position of the support block in the transverse direction (ie, the axial direction of the tool) is not properly selected, a qualified slender bar tool cannot be machined. If the support block is too low, the support force for the tool is not enough, which will cause the sipe to form an inverted cone in the axial direction. If the support block is too high, the support block will be hard against the tool and cause the sipe to form a forward taper in the axial direction. Therefore, the accurate positioning of the support block is also important for the accuracy of the tool.
Second, the impact of grinding wheel on tool accuracy. All parameters of the tool are determined by the relative motion of the grinding wheel and the tool. Therefore, the diameter of the grinding wheel, the angle at which the grinding wheel directly participates in the cutting, the length of the flange of the grinding wheel shaft, the wear of the grinding wheel, and the grain size of the grinding wheel all influence the accuracy of the tool. Grinding Wheel Angle Measurement or Input Accuracy The grinding wheel angle measurement or inaccurate input may result in: The blade width is not consistent with the requirements; the stepped tool step surface angle does not meet the requirements; the tool back angle position or angle error; chip flutes Groove angle error and so on.
Third, the coolant cooling effect on the grinding zone will directly affect the accuracy of the tool. The selection of excellent coolant and proper cooling pressure facilitates the entry of coolant into the grinding zone, removing the cutting heat and cuttings in time, and effectively reducing the tool surface roughness.
Characteristic and performance analysis of main parts of generator
Stator:
Stator consists of base, stator core and stator windings.
The base is welded by steel plate, the structure is light and sturdy, and the base is divided into many air inlet and outlet zones in the axial direction;
Stator coil:
It is stacked by strands of copper wire covered by polyester glass fiber, with half-unit type and basket shaped structure (parts of stator coils use transposition structure). The insulation grade of the stator coil is F grade. The stator coil is shaped by continuous wrapping and mould pressing with mica tapes. The coil end is firmly tied up to the support and the bundling ring with unidirectional tapes or dacron-glass ropes thus the turbo-generator unit became highly resistant towards sudden short-circuit conditions.
Stator core:
Stator core is punched and stacked by cold rolled non-oriented, high permeability, low loss high-quality silicon steel sheet, both sides of the silicon steel sheet are coated with a solid insulating film to prevent short-circuit between the stator core pieces to reduce eddy current loss.
Rotor:
The rotor is composed of shaft, coil, center ring, shroud ring and fan ring etc. The rotor coil is made of cold-drawn flat copper wires, and processed by oxygen-free annealing. The rotor coil of generator with 50MW and above is welded together by silver-bearing cold-drawn copper wires and adopts F grade insulation.
The shroud ring at rotor coil end is made of non-magnetic steel. Both ends of the rotor are equipped with centrifugal fan or axial flow fan with paddle fan blade which is forged by high-strength aluminum alloy.
Rotor machining:
The generator shaft is forged from an integral high-quality alloy steel and has an axial groove formed thereon for fitting a rotor coil and an air groove or a crescent groove is made in the large tooth to enhance the cooling of the main body and the coil end. The slots are processed by special machine for generator rotor processing, Tacchi high precision horizontal slotting and milling machine made in Italy, to ensure the high efficiency of generator.
The generator rotor must be subjected to high-speed dynamic balancing experiment and dynamic impedance experiment before delivery to verify the mechanical strength of the rotor and ensure excellent inter-turn insulation of the rotor windings.
(2)Model
Mainly produce the following model Steam Turbine Generator and the specifications are as follows:
Voltage(KV) Frequency(HZ) Power(MW)
2 poles Steam Turbine generator 6.3-3.8 50 3-60
6.6-13.8 60
4 poles steam turbine generator 0.4/0.69 6.3/6.6 10.5/11 50 0.5-30
0.4-11 60
QNP steam turbine generator uses closed-loop air self-circulation ventilation.
The rotors of turbo-generator under 50MW adopt indirect ventilation cooling method;
The rotors of 50MW and above turbo-generator is directly ventilated and cooled; an auxiliary groove is machined under the rotor winding trunking; air vents are machined on the rotor windings; with the action of the fan head and the centrifugal pressure head of the air vents, the rotor windings are directly cooled by air from the auxiliary groove and air vents.
(4)Excitation mode
QNP's steam turbine generator can adopt static silicon controlled type, two-pole AC brushless excitation and three-pole AC brushless excitation, three kinds of excitation mode.
(5)Insulation system
Adopt class F insulation materials and insulation structure, during the running time, assess the system according to class B insulation grade, meanwhile some margin has been kept.
(6)Design and acceptance criteria
Design, manufacture, inspection are carried out according to the relevant national standards, at the same time can meet the International Electrotechnical Commission IEC34-1 latest standards. According to customer`s requirements, QNP`s steam turbine generator can also be designed, manufactured and accepted according to ANSI, NEMA and other international standards.
(7)Technical Performance Analysis
1.Output margin
The series of steam turbine generator of QNP keeps 10% output margin.
2.Loss and efficiency
The steam turbine generator of QNP optimized the design and farthest minimized the additional loss and wind abrasion of generator under no-load and short-circuit condition, improved the efficiency of the generator, in general, QNP steam turbine generator`s efficiency is 0.2% higher than domestic similar models in this industry. It is higher than the national efficiency standard on the same capacity level. For example: QNP 15MW steam turbine generator`s efficiency value can reach 97.65%, and the national standard value is 97%.
3.Running reliability
QNP's steam turbine generator adopts advanced manufacturing technology, especially the rotor`s overspeed test uses high-speed dynamic balancer, rotor`s balance precision has been greatly improved, and the rotor`s vibration value is decreased. So that the steam turbine generator`s running availability factor has been improved, and the unit`s forced outage rate is decreased. At present, the availability factor of the steam turbine generator can reach about 99%, and the forced outage rate fell to 0.04% to 0.4%. Overhaul interval is up to 5 years. And the unit life can reach to 35 to 40 years.
Model meaning
QFWD-3-2A
QF Steam turbine generator
W W means brushless, without W means static silicon controlled
D D means double support, without B means single support
3 Rated power
2 2 means two poles and means the rated rotation speed is 3000 r/min
4 means four poles and means the rated rotation speed is 1500 r/min
A means the design serial number: A.B.C.D
Steam Turbine Generator,Biomass Generating,Biomass Generation,Biomass Power Generation
Shandong Qingneng Power Co., Ltd. , https://www.qnpturbines.com