CN201312278Y

CN201312278Y - Middle and high voltage, high power motor soft starter

Info

Publication number: CN201312278Y
Application number: CNU2008201592177U
Authority: CN
Inventors: 郭少仪
Original assignee: Individual
Current assignee: Individual
Priority date: 2008-11-14
Filing date: 2008-11-14
Publication date: 2009-09-16
Anticipated expiration: 2018-11-14

Abstract

The utility model discloses a middle and high voltage, high power motor soft starter, comprising over-current fuses connected with each phase of a power supply, and a transformer whose primary current is equal to the critical value for starting motor when the secondary coil is opened, wherein the transformer is serially connected between a three-phase power supply and a controlled motor via an alternative current contact and is connected with an alternative current contact on the main circuit in parallel; the secondary coil of the transformer is connected with an intelligent control module. The middle and high voltage, high power motor soft starter has low pulse interference on power network, effectively resolves the motor start problem, has compact structure, low cost and small volume, and prolongs the service life of motor.

Description

Middle and high pressure soft start of high-power motor device

Technical field

The utility model relates to a kind of soft starter, specifically is a kind of middle heavy-duty motor and high-voltage high-power motor soft starter of pressing.

Background technology

Publication number is CN101222192, name is called: the low pressure that three-phase commutation bridge is formed and the patent of invention of high pressure soft starter, disclose a kind of soft starter, motor stator three phase windings are inserted the three-phase full-controlled rectifier bridge AC side and the rectifier bridge DC side has just been formed the low pressure soft starter with the lead connection; Three-phase saturation electric reactor low-voltage alternating-current magnet exciting coil is inserted the three-phase full-controlled rectifier bridge AC side, and the rectifier bridge DC side is communicated with lead, with high-voltage motor three-phase stator winding and saturable reactor high-tension coil polyphone, just formed the high-voltage motor soft starter again.There is following defective in it:

1, use the three-phase commutation bridge control module, must be connected on the end of motor windings, can only be suitable for star connection, the diabolo connection is inconvenience then.

What 2, its transformer method adopted is general transformer, and for electric motor starting, starting current is several times of rated operational current, must cause this volume of transformer big, Heavy Weight, the cost height is very big to the pulsation interference effect of electrical network.

The correlation technique of other relevant high pressure soft startings is to adopt the principle of similar transformer equally, with the marginal variable reactor of making Based Intelligent Control that cooperates with thyristor, just transformer is serially connected between electrical network and the motor the therefore same problem that exists as hereinbefore.For general transformer, for improving primary and secondary energy conversion efficiency, elementary no-load current is very little, has only the secondary load electric current is brought up to enough greatly, could reach the required current value of electric motor starting by primary.And control module is subjected to withstand voltage restriction, and the primary and secondary ratio of transformer is got the step-down mode, and therefore, required secondary current is incited somebody to action increase at double.This obviously is difficult to bear for high-voltage high-power motor.

The utility model content

At the defective that above-mentioned prior art exists, the utility model aims to provide a kind of middle and high pressure soft start of high-power motor device, can overcome above defective, reduction is to the impulse disturbances of electrical network, simultaneously can solve the electric motor starting problem, reduce cost, and prolong motor useful life.

For achieving the above object, the concrete technical scheme that the utility model is taked is, a kind of middle and high pressure soft start of high-power motor device, when comprising the overcurrent insurance that is connected each phase power supply and secondary open circuit, the transformer of critical value when primary current is equivalent to electric motor starting, described transformer is serially connected with between three phase mains and the controlled motor by A.C. contactor, and in parallel with the A.C. contactor on the major loop, and described transformer secondary output is connected with intelligent control module.

Operation principle of the present utility model is: described medium and high pressure soft start of high-power motor device comprises the overcurrent insurance that is connected each phase power supply, can prevent effectively that overload current from surpassing the rated value of contactor and other components and parts, so that the fault that surpasses the components and parts protection range is effectively protected; The transformer that is serially connected between three phase mains and the motor can make motor when starting by A.C. contactor, by transformer control operation, realizes soft start; After starting normally, switch to operating loop, realize operate as normal.

Design of transformer is in the utility model, when secondary open circuit, and the critical value the when electric current that flows through primary is equivalent to electric motor starting.Promptly under secondary open-circuit condition, as long as a power turn-on, motor just is in critical starting state.Then, according to the rotating speed of motor signal, control connection is replenished the primary current value in the unlatching of secondary intelligent control module, can make it finish the startup of motor by predetermined requirement.Like this, the electric current that intelligent control module passes through is the fraction of the required electric current of starter motor, can reduce the requirement to intelligent control module greatly.

The secondary of transformer also can be adopted the low pressure multiple secondary winding, adopt parallel connection method, the intelligent control module that is connected transformer secondary output can adopt low pressure, limited current module to reach the purpose of high pressure, heavy-duty motor start-up control, has improved the reliability and the utilization property of work greatly.

In sum, the utility model makes the transformer secondary output open circuit realize the control of variable reactance formula by specific transformer, and is than controlling with thyristor merely, much smaller to the impulse disturbances of electrical network.Press the starting problem of heavy-duty motor and high-voltage high-power motor in efficiently solving, its compact conformation, cost is lower, and volume is little, and has prolonged motor useful life greatly.

Description of drawings

Fig. 1 is the main circuit schematic diagram described in the embodiment;

1-overcurrent insurance 2-knife switch 3-A.C. contactor C1

4-A.C. contactor C2 5-three-phase transformer

6-A.C. contactor C3 7-motor 8-intelligent control module

Embodiment

As shown in Figure 1: middle and high pressure soft start of high-power motor device comprises overcurrent insurance 1 and the secondary three-phase transformer 5 that is connected with intelligent control module 8 that is connected each phase power supply.To 380V, 220KW three phase electric machine 7, load starts, when unloaded, elementary firm startup transient voltage is 140V, about 1000 amperes of electric current, transformer adopting single level structure, transformation ratio is 2: 1, and the intelligent control module 8 of secondary connection is 450v, the commercially available three-phase alternating current control module of 1000A.A.C. contactor C1 is a run switch, the operational system when it and motor D constitute operate as normal; C2, C3 are starting switch, and it and three-phase transformer 5 constitute start loop.When motor starting, the C2 that closes, C3 realize soft start; Behind the proceed-to-send, the A.C. contactor C1 that closes, disconnection C2, motor promptly changes running status over to.

Claims

1, a kind of middle and high pressure soft start of high-power motor device, when it is characterized in that comprising the overcurrent insurance that is connected each phase power supply and secondary open circuit, the transformer of critical value when its primary current is equivalent to electric motor starting, described transformer is serially connected with between three phase mains and the controlled motor by A.C. contactor, and in parallel with the A.C. contactor on the major loop, described transformer secondary output is connected with intelligent control module.