Brushless joint-control motor soft starter

Abstract

The invention discloses a brushless joint-control motor soft starter used for a wound-type alternating-current asynchronous motor. Compared with the conventional brushless self-control soft starter, the brushless joint-control motor soft starter has the characteristics that: the joint sequence control of a water resistor, a shorting switch and a safety exhaust valve avoids a liquid spray phenomenon; 2, the water resistor adopts a graphite pole plate and is contacted before the shorting circuit, so that the electro erosion of the pole plate of the water resistor is reduced, the phenomenon of the fusion welding of a moving contact and a fixed contact of the shorting switch is avoided; 3, the on and off states of the shorting switch are controlled by two units respectively, so that the jumping phenomenon of the moving contact and the fixed contact is avoided, and the contact pressure of the contacts is improved; 4, the contact time of the shorting circuit and the water resistor can be conveniently regulated after leaving a factory, so that the adaptability is improved; 5, a safety valve and an exhaust valve are integrated and are linked with the shorting switch, so that the number of seal surfaces is reduced and the starter is convenient to maintain; and 6, according to different users, different implementation modes can be adopted, and the manufacturing cost is reduced.

Description

technical field [0001] The invention relates to a starter for a wire-wound AC asynchronous motor, more specifically a device for realizing the brushless joint control start of a wire-wound AC asynchronous motor by using water resistance. technical background [0002] The published invention patent "Brushless Self-Control Motor Soft Starter" (Patent No.: ZL03112809.2) installs the water resistance on the motor shaft, uses the centrifugal force generated when the motor rotates to control the size of the water resistance, and realizes the winding AC Brushless self-controlled soft start for asynchronous motors. But: ①. Since the moving and static plates and contacts of the water resistance are installed in the electrolyte and are made of metal, the electric corrosion problem of the plates cannot be solved. As a result, after the motor starts, the starting resistance cannot be reduced to zero, resulting in The starter generates heat, which wastes energy; ②, the water resistance,...

AI Technical Summary

Problems solved by technology

But: ①, the structure of the moving contact device of the pole plate is complicated, it is inconvenient to adjust the contact speed of the moving and static pole plates, and it is impossible to adjust the short-circuit timing of the pole plate after the starter leaves the factory; Anti-welding, but the contact resistance is large, the starter will generate heat after operation, and waste energy; ③, the structure of the exhaust valve is complicated, and the seals are difficult to repair. When the internal components are damaged (such as the exhaust valve lever is damaged), it will cause Integral failure of the exhaust valve

[0004] The published utility model patent "Brushless self-controlled motor hydraulic resistance soft starter" (Patent No.: ZL200920091386.6) uses the centrifugal force of the motor rotation to directly control the opening and closing of the short circuit switch, avoiding the need for the switch contacts to be installed in the electrolyte But: ①, the starting resistance is fixed and cannot be automatically reduced according to the motor speed; while the motor rotor voltage is proportionally reduced to the motor speed, causing the motor starting current and torque to decrease proportionally to the motor speed ;When the starting torque is less than the load torque, it will cause the failure of the motor to start; ②, the short circuit switch is only controlled by centrifugal force, and it is a one-time short circuit, the short circuit speed is small, and the contact welding is easy to occur; ③, When the motor load changes, the jump of the short-circuit switch contact is caused by the fluctuation of the motor speed, which further reduces the service life of the starter; ④. The exhaust valve is fixedly installed on the outer ring of the starter. , the electrolyte in the catheter will be discharged, resulting in the loss of electrolyte; ⑤, due to the small diameter of the catheter (the pipe assembly causes too much liquid to be discharged every time it is started), if the motor fails to start, it cannot be started in time Exhaust the gas generated by the water resistance, there is a danger of explosion

[0005] Based on the above starting devices, it can be concluded that: ①, no starter can automatically accelerate the speed of water resistance reduction according to the change of motor load, increase the starting current and torque of the motor, and avoid the occurrence of motor starting failure

②. There is no starter with variable water resistance and short-circuit switch at the same time, that is, it cannot have the dual functions of high starting performance and low operating loss at the same time; ③. Switch contacts or water resistance plates The contact is completed at one time, which cannot solve the contradiction between the small contact resistance and the welding of the contacts; ④, the control of the short circuit switch or the water resistance plate is single, and the closing and opening of the switch or the plate cannot be controlled separately, resulting in The contradiction between reducing the inrush current when the motor starts and avoiding the jumping of the switch contacts cannot be resolved; ⑤. It is inconvenient to adjust the contact timing of the short circuit switch or water resistance, or the corresponding adjustment device is not installed, and the starter has poor load capacity to adapt to different motors ; ⑥. The exhaust valve and the safety valve are set separately, or jointly set on the outer cylinder of the water resistance container, the structure is complex, the sealing surface is many, and the installation and adjustment are inconvenient; explosion hazard

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