Submersible pumps, circulation pumps, booster pumps.
1. Submersible Pump: Used to pump water from water bodies to meet the needs of agriculture or power generation.
2. Circulation Pump: Used to circulate water to maintain the cleanliness and oxygen content of the water body.
3. Booster pump: Used to increase water to meet high voltage power transmission needs.
Three-phase motors can be converted into generators for general lighting by adding external capacitors and drive power. The external capacitor is divided into a main capacitor group and a sub-capacitor group. The main capacitor bank is mainly a capacitor that allows the generator to self-excite to reach the rated no-load output voltage. to a capacitor necessary to maintain theThe output voltage at the nominal value under load must be added. If the selected capacitor has a withstand voltage value of 250 V, it should be connected in a Y shape. If the capacitor has a withstand voltage value of 400 V, it can be connected in a △ shape. The connection method is shown in Figure 1. The capacity of the main capacitor bank is determined according to the motor power, as shown in the following table: Motor power (KW) Rated current (A) Capacitor capacity (△) Capacitor capacity (Y) 1 2.4 7--12uf 21-36uf 1.7 3.9 9 --14uf 27--41uf 2.8 6.1 15--21uf 45--63uf 4, 5 9.5 20--28uf 60--84uf 7 14.5 28--38uf 84--114uf 10 20 38--52uf 114 --156uf 14 27.4 50 --70uf 150--210uf 20 38.4 64--84uf 192--240uf 28 53 80--110uf 240--330uf The secondary capacitor is determined according to the load. All capacitors are non-polar capacitors. . In addition, so that the engine can stimulate the penergy production, there must be a residual magnetic flux in the rotor. If power cannot be generated normally after connecting the wires, it may be because the rotor lacks residual magnetic flux. can use a 6V DC supply to randomly power one phase of the motor. A few seconds after the winding is energized, the rotor will generate residual magnetism. Motor to generator Generally, a single-phase asynchronous motor can be converted into a generator by simply connecting two capacitors to two windings, which is very convenient. A three-phase asynchronous motor can be connected to a capacitor on each winding, then the remaining three legs are connected together to form a star connection. The voltage between the phase line and the neutral line is 220 V. The three-phase motor can be converted into a generator for general lighting by adding an external capacitor and a frno power. The external capacitor is divided into a main capacitor group and a sub-capacitor group. The main capacitor bank is mainly a capacitor that allows the generator to self-excite to reach the rated no-load output voltage. to a capacitor necessary to maintain the output voltage at the nominal value under load must be added. If the selected capacitor has a withstand voltage value of 250 V, it should be connected in a Y shape. If the capacitor has a withstand voltage value of 400 V, it can be connected in a △ shape. The capacity of the main capacitor bank is based on the motor power size is determined. The secondary capacitor is determined based on the load. All capacitors are non-polar capacitors. Additionally, for the motor to stimulate power production, there must be residual magnetic flux in the rotor. If theEnergy cannot be generated normally after connecting the wires, this may be because the rotor lacks residual magnetic flux. can use a 6V DC supply to randomly power one phase of the motor. A few seconds after the winding is energized, the rotor will generate residual magnetism. In Tibet, due to natural conditions, lack of funds and other reasons, 30% of rural areas in Tibet have not yet used electricity from Tibet's large power grid. Instead, they rely on hydropower from mountains and streams. providing electricity for lighting and drinking water to farmers and shepherds. At present, there are many cases of asynchronous motors replaced by generators in rural areas of Tibet. This is due to their advantages such as simple structure, easy maintenance, easy operation and low cost. I'm going toNow present some of my experience in converting asynchronous motors into generators in rural areas as follows: 1. Generator Excitation Mode There are two excitation modes for generators. One is called separate excitation mode. This method is established by providing an excitation current. the electrical network. This method cannot be used in rural areas where there is no other power supply. The other is called self-excitation method, which relies on its own residual magnetism and a set of capacitors connected to the stator coil to self-excite. This method is widely used in rural areas. 2. Selection of self-excited asynchronous motors and power generation conditions (1) In order to simultaneously meet the power consumption of power and lighting loads, an asynchronous motor with a "Y" type connection must generally be selected for easeliter the extraction of the neutral line. (2) In order to reduce costs, an asynchronous motor with a capacity of less than 15 kW and a voltage of 380/220 V should be selected. (3) The motor speed should be selected slightly lower than the main motor speed. The main engine speed is usually about 5% to 10% higher than the engine speed during the same period. (4) There must be a certain amount of residual magnetism on the motor rotor. (5) An excitation capacitor of appropriate value should be connected in parallel. 3. Selection of no-load excitation capacitance and load parallel capacitance It is very important to correctly select the no-load excitation parallel capacitance. If the capacity is selected too large, the no-load voltage will be too high, which may damage the equipment. ; if the capacitance is selected too small, the no-load voltage will be too low. The excitation capacitorNo-load operation should be selected so that the voltage generated by the generator does not exceed the rated voltage specified on the nameplate. Under this condition, the required excitation capacitor Co (according to the no-load connection method "△") can be calculated by the following formula: (1) In the formula, IO - the no-load excitation current A under UN ? — the rated line voltage of the motor V CO — the no-load excitation capacity μF For the three-phase total capacity according to the “Y” connection method, you can press the formula Calculation: C0=106*3I0/314UNx (. 2) In the UNX formula: the rated phase voltage V of the motor when the motor is loaded with a load, the generator voltage decreases with increasing load. Therefore, the capacity must be compensated when operating with a load. When the power factor of the load cosφ = 1 (i.e. a pure resistive load) and the load is full, sinceactive power causes immobile losses in the electrical network, a capacitor must be added to compensate for the reactive power in the load. The compensation capacitance value can be estimated as follows: ?C1=1.25CO (3) FormulaAverage?C1 ——Compensation capacitance value μF when loading When the power factor cosφ of the load is about 0 ,8, because there is an inductive load in the load, in order to compensate for the loss of reactive power caused by the reactive power in the load. power network, the corresponding compensation capacitor must have a value, the compensation capacitance value C2 can be calculated according to the following formula: C2 = 0.6SN/314UN2 (4) Where C2——Compensation reactive power capacitance value μF SN——The rated capacity VA of the asynchronous motor at rated load The total load compensation capacity C is: ?C=C1+C2 (5) The total value of the three-phase excitation capacity is: Ctotal=CO+C=CO+C1+C2 (6) For example, there is a motor J02-71-8, rated power Pe = 17 kW, rated speed 720 rpm, rated voltage 380 V, rated current 35, 8 A, Y type connection, power factor 0.8, no-load current 5.5 A (nameplate value), it must now be replaced by an asynchronous generator. What are the empty capacity and the load capacity? Substituting the above data into formulas (1), (3), (4) and (5), the no-load capacitance is 78 μF and the total load compensation capacitance is 322.4 μF. 4. Precautions during operation (1) In order to ensure the quality of the power supply voltage, the compensation capacity should be increased or decreased as the load changes. (2) The load should be applied after the no-load voltage of the generator has increased, otherwise the generator voltage will be difficult to establish. (3) The electrical load must not exceed 25% of the generator capacityand the single engine capacity shall not exceed 10% of the total generator capacity. Otherwise, the starting current will be too large and the voltage will drop sharply. and the engine will be difficult to start.