Motor buffer starting control system having energy saving and power saving

Abstract

The invention relates to a motor buffer starting control system having energy saving and power saving. Four sets of control equipment, namely a motor buffer starter, an automatic power factor adjuster, an electronic discharger and a static switch are integrated to form an integral module, the motor starting and running current can be effectively reduced, the service lifetime of power system equipment is prolonged, a power factor is put in real time, no delay phenomenon is generated, so that the power quality reaches a set standard, a power system more effectively and normally works, the equipment of a power company and the power utilization cost of an enterprise are reduced, and the essential benefit is improved; the static switch which is employed has functions of rapid zero-point puttingand zero-point switching; and the motor buffer starting control system has a function of the moor buffer starter, and the starting current and the running current of a motor can be simultaneously andsubstantially reduced.

Description

technical field [0001] The present invention is related to motor control, in particular to an energy-saving and power-saving motor buffer start control system. Background technique [0002] At present, there are many factories installing large motor loads of more than 100 horsepower, among which induction motors have the highest proportion. Due to the starting current of induction motors, it is generally about 5 to 8 times the full-load operating current, and the starting current of medium and large induction motors is too large. It will cause the burden of the power system and affect the power supply quality and stability of the power system. Therefore, when the medium and large induction motors are started, a starter should be installed to limit the starting current, but it must be able to provide enough torque to drive the load. , so that the motor can start and run normally. [0003] In order to reduce the starting current of the induction motor, the Y-Δ starting method...

AI Technical Summary

Problems solved by technology

[0002] At present, there are many factories installing large motor loads of more than 100 horsepower, among which induction motors have the highest proportion. Due to the starting current of induction motors, it is generally about 5 to 8 times the full-load operating current, and the starting current of medium and large induction motors is too large. It will cause the burden of the power system and affect the power supply quality and stability of the power system. Therefore, when the medium and large induction motors are started, a starter should be installed to limit the starting current, but it must be able to provide enough torque to drive the load. , so that the motor can start and run normally

[0003] In order to reduce the starting current of the induction motor, the Y-Δ starting method is generally adopted. The purpose is to pull out the 6 wires of the stator of the three-phase induction motor and connect them to Y wiring when starting. After the starting current drops to a stable value, the wiring is connected. Change to Δ connection for full voltage operation, because the phase current in Y connection is Δ connection And the voltage of each winding is only connected by Δ Therefore, the starting current of the Y connection is actually only the Δ connection. The advantage of this connection method is simple wiring, low cost, and can effectively reduce the starting current. The disadvantage is that the starting torque is small and the acceleration is slow. It is only suitable for motors with 5 to 15 horsepower, and those who can start without load

[0004] Therefore, the Y-Δ starting method has many disadvantages. In addition, the factory installs a motor with more than 100 horsepower, which causes problems such as high instantaneous current at the start of the motor load, very low power factor, and high voltage drop of the wire; therefore, the market There is a traditional starter motor controller developed. Although there is an automatic power factor regulator (Automatic Power Factor Regulator, APFR) at the power supply end, it can reduce the motor running current; however, a magnetic contactor (Magnetic Contactor, MC) is used to control the movement. If the time is too long, the starting current of the motor cannot be effectively reduced immediately

[0005] In view of the long distance between the large motor in the factory and the main power transformer (about 50-150 meters long); although it contains an automatic power factor regulator, it can reduce the operating current of the motor; and the action time controlled by the electromagnetic contactor is too long. The maximum starting current of the motor cannot be effectively reduced immediately after the motor starts for a short period of time (minutes or seconds), resulting in problems such as high instantaneous current at startup of large motor loads, very low power factor, and high voltage drop of wires.

The traditional Y-Δ start-up method (such as figure 1 As shown), it is a Y-Δ starter 1' directly connected to a motor M', and the Y-Δ starter 1' is connected to a three-phase AC power supply through a no-fuse (NFB) switch S' P' electrical connection, the advantages of this connection method are simple wiring, low cost, and can effectively reduce the starting current. The disadvantage is that the starting torque is small and the acceleration is slow. For load starters, the factory installs a motor with more than 100 horsepower, which causes problems such as high instantaneous current at startup, very low power factor, and high voltage drop of wires in the factory where the motor is loaded.

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