CN202435323U

CN202435323U - Switching control device of auto-transformer

Info

Publication number: CN202435323U
Application number: CN201220002822XU
Authority: CN
Inventors: 卢铭; 黄美琼
Original assignee: Guangxi Yuchai Machinery Co Ltd
Current assignee: Guangxi Yuchai Machinery Co Ltd
Priority date: 2012-01-05
Filing date: 2012-01-05
Publication date: 2012-09-12
Anticipated expiration: 2022-01-05

Abstract

The utility model discloses a switching control device of an auto-transformer, which comprises a main power supply switch, two alternating current contactors and a timing programmable controller, wherein the two alternating current contactors can be used for respectively controlling a motor and the auto-transformer. After the main power supply switch is closed, the two alternating current contactors are controlled by the timing programmable controller to establish electrical connection between a winding of the auto-transformer and the motor, and the timing is started, and the timing programmable controller controls the two alternating current contactors to disconnect the electrical connection and the alternating current contactors of the control motor are kept in a closed state when the timing is over. The switching control device of the auto-transformer can securely operate under the condition of large current.

Description

The autotransformer control switch device

Technical field

The utility model relates to a kind of transformer control switch device, particularly a kind of autotransformer control switch device.

Background technology

Single-circuit transformer generally is applied in the heavy-duty motor start-up course, helps heavy-duty motor to start, and plays the effect that reduces voltage, shares electric current, i.e. reduced-voltage starting.Require three windings (all or part of) of single-circuit transformer to connect with motor three phase windings respectively on its electrical wiring; After the electric motor starting signal sent, single-circuit transformer put into operation, after motor reaches certain rotating speed; Single-circuit transformer is out of service, is moved by the motor total head at last.In this process, control autotransformer and withdraw from from putting into through the time relay and diverter switch are set in control circuit.Diverter switch initially is closed, can make during starter motor to form between winding and the motor of autotransformer to be electrically connected.When the time relay finished in timing, the tripping of meeting control its switch was broken off the winding of autotransformer and motor, thus the motor independent operating.

But; This autotransformer is in operation and often is under the big current condition, and devices such as the diode in the circuit board of the time relay, electric capacity, resistance are easy to excessive heating under the operating mode of big electric current, influence the life-span of components and parts; Cause the misoperation of the time relay easily; For example timing then and not produces output, and perhaps automatic tripping etc. under closure state can not normally start motor.Therefore, need to occur a kind of more autotransformer control switch device of high stability that has.

The utility model content

The utility model is in order to overcome above-mentioned defective of the prior art, disclose a kind of can be under big current condition the autotransformer control switch device of trouble free service.

For realizing above-mentioned purpose, the openly following technical scheme of the utility model:

A kind of autotransformer control switch device; Comprise main power switch, control two A.C. contactors and the timing Programmable Logic Controller of motor and autotransformer respectively; Wherein: said timing Programmable Logic Controller is set up between the winding of autotransformer and motor at said two A.C. contactors of control after the said main power switch closure and is electrically connected and picks up counting, control again when timing finishes said two A.C. contactors break off this electricals connection also the A.C. contactor of retentive control motor be in closure state.

Preferably, said timing Programmable Logic Controller is any among Siemens Programmable Logic Controller s7-200, s7-300 or the s7-400.

More preferably, the timing duration of said timing Programmable Logic Controller is 7 seconds.

Compared with prior art, the utlity model has following beneficial effect:

1, adopt PLC to replace original time relay and corresponding diverter switch, because PLC can safe operation under big electric current, so avoided the time relay overheated impaired defective easily;

2, the timing numerical value of PLC, input/output control mode can utilize program to adjust easily, thereby have increased the use flexibility and the modification scope of the utility model;

3, Siemens s7-200/300/400PLC is ripe industry control PLC, under big current condition operation as safe as a house, be particularly useful for as the autotransformer control switch device;

When 4, the timing duration is 7 seconds, the rotating speed behind the electric motor starting tend to be steady basically and circuit in caloric value little, be suitable for the switching of autotransformer control.

Description of drawings

Fig. 1 is existing a kind of autotransformer control circuit;

Fig. 2 is the control section schematic diagram of the utility model;

Fig. 3 is the control program ladder diagram of PLC among Fig. 2.

Embodiment

Below in conjunction with accompanying drawing, the preferred embodiment of the utility model is described in detail, but the protection range that is to be understood that the utility model does not receive the restriction of embodiment.

Fig. 1 is existing a kind of autotransformer control device sketch map, wherein controls the cut-out between the winding of motor M and autotransformer TM with a time relay KT.Under the condition of work that is in big electric current for a long time, the electronic component among the time relay KT is easy to because overheated and damage.Shown in the title of each component symbol sees the following form among Fig. 1:

Code name	Title	Code name	Title
				M	Threephase asynchronous	KM2	A.C. contactor
TM	Single-circuit transformer	KA	Auxiliary relay
				FU1	The major loop fuse	KT	The time relay
FU2	The control loop fuse	SB1	The stop button switch
				KM1	A.C. contactor	SB2	The start button switch
L1、L2、L3	Three-phase power input end	FR	Thermal relay
				D1、D2、D3	The motor terminals	PE	Ground connection

Its operation principle is following:

(1) reduced-voltage starting: press SB2 → KA coil get electric → KA self-locking contact closure self-locking → KT coil and KM2 coil all electric → KM2 main contact closure → KM2 locking contact disjunction is inserted the reduced-voltage starting with motor M to KM1 interlocking → single-circuit transformer TM;

(2) total head running: when motor speed rose near rated speed, time relay KT timing arrived, and KT normally closed interlock elder generation disjunction → normally closed auxiliary contact disjunction of KM2 coil losing electricity → KM2 is interlocked to KM1; KT normally open contact closure → KM1 coil then gets electric → KM1 self-locking contact closure self-locking → KM1 main contact closure → motor M and is connected into △ (triangular form) total head operation, presses SB1 when stopping and getting final product.

Fig. 2 is the schematic diagram of the control circuit part of the utility model; L1-L3 represents three phase lines of main power source among the figure, and QS is a main power switch, and FU is the major loop fuse; KM1 and KM2 are respectively two A.C. contactors that controlled by the output contact of PLC; Break-make between KM1 control motor M and the main power switch QS, the break-make between KM2 control autotransformer TM and the main power switch QS, FR is the thermal relay on the motor M.The PLC here preferably has any among Siemens PLC Cs7-200, s7-300 or the s7-400 of timing function.

Shown in Figure 3 is the control program ladder diagram of PLC among Fig. 2, and the title of each symbol and function corresponding relation are as shown in the table among the figure:

According to program shown in Figure 3, when QS connected, the normally opened contact of KM2 was closed, normally-closed contact is opened, and autotransformer TM supplies power to motor M; After timing in 7 seconds finished, the normally opened contact of KM2 was opened, normally-closed contact is closed, and make that the electrical connection between autotransformer TM and the motor M is broken off, and the normally opened contact of KM1 was closed, and L1-L3 directly supplies power to motor M.

More than the disclosed more excellent specific embodiment that is merely the utility model, still, the utility model is not limited thereto, any those skilled in the art can think variation all should fall into the protection range of the utility model.

Claims

1. autotransformer control switch device; It is characterized in that; Comprise main power switch, control two A.C. contactors and the timing Programmable Logic Controller of motor and autotransformer respectively; Wherein: said timing Programmable Logic Controller is set up between the winding of autotransformer and motor at said two A.C. contactors of control after the said main power switch closure and is electrically connected and picks up counting, control again when timing finishes said two A.C. contactors break off this electricals connection also the A.C. contactor of retentive control motor be in closure state.

2. autotransformer control switch device according to claim 1 is characterized in that, said timing Programmable Logic Controller is any among Siemens Programmable Logic Controller s7-200, s7-300 or the s7-400.

3. autotransformer control switch device according to claim 1 is characterized in that, the timing duration of said timing Programmable Logic Controller is 7 seconds.