CN201839170U

CN201839170U - Monophase electric machine with starting current limiting device

Info

Publication number: CN201839170U
Application number: CN2010201162509U
Authority: CN
Inventors: 徐东旭
Original assignee: Individual
Current assignee: Individual
Priority date: 2010-02-23
Filing date: 2010-02-23
Publication date: 2011-05-18
Anticipated expiration: 2020-02-23

Abstract

The utility model provides a monophase electric machine which is self-provided with a starting current limiting device and is additionally provided with a limiting starting-current device in the electric machine. The monophase electric machine can overcome the influence of large currents on a power grid in the starting process of the electric machine, and can improve the starting characteristic index of the electric machine; the reactive resistance of a main winding circuit is added by the starting current limiting device in the starting process of the electric machine; and in the normal operation, the connection is switched into a normal working state by a special centrifugal switch. As the comprehensive starting current limiting device consists of an electronic switch and a current-limiting resistor, the power loss of a current-limiting component is greatly reduced, and the whole starting current limiting device can be conveniently contained into the electric machine.

Description

Monophase machine from the tape starting current-limiting apparatus

Technical field:

The utility model relates to a kind of special centrifugal switch conversion work state of using, from the monophase machine of tape starting current-limiting apparatus.

Background technology:

No matter three-phase or monopole asynchronous motor, all be by the required Winding Design of carrying out of normal operation, inevitable reality, be the several times that electric current when starting initial (or stall) surpasses normal operating current, running current reduces along with the raising of rotating speed, reduces to specified numerical value after reaching rated rotational frequency.

Be the influence of the big electric current that overcomes the electric motor starting process to electrical network, normally in the distribution line of the equipment of commercial Application motor (generally at three phase electric machine), use conversion and control down block or change winding connection methods such as various switches or A.C. contactor, the voltage that reduces motor windings suppresses the electric current of electric motor starting process.

Summary of the invention:

For overcoming the influence that the big electric current of monophase machine start-up course causes electrical network, improve the starting characteristic index of motor, it is a kind of the device of restriction electric motor starting function of current that the utility model provides, and is integrated into the monophase machine from the tape starting current-limiting apparatus of motor internal.

Concrete technical measures, key are to change the structure of the common centrifugal switch that break contact is only arranged, and become to possess moving closing and the special centrifugal change over switch that moves disconnected transfer contact simultaneously; Utilize transfer contact at start-up course series connection current limliting assembly or disconnect two-wire and around motor, and around the part bridging coil of main winding, source current is by current limliting assembly and main winding series circuit the part of winding in parallel (or only flow through), because of the increase of circuit reactance reduces; When reaching desired speed and entering normal operation, the break contact of centrifugal switch disconnects auxiliary winding and starts electric capacity; And make contact short circuit current limliting assembly (Fig. 2) or connect main winding remainder (Fig. 3) is finished the regular path of motor main winding.

Because starting initial when stall (or) especially, the resistance of lead accounts for the leading position of reactance, and above-mentioned another approach that reduces winding wire diameter (in a disguised form increasing the main winding reactance) can be to use the aluminum steel coiling to start the coil of connecting part.

The simplest current limliting assembly of the utility model can directly use the finished product resistor of determining resistance by calculating or experimental result, perhaps directly makes the resistor that is fit to resistance with the various materials that possess suitable resistance.

Better the current limliting assembly is to use electronic components such as triode, field effect transistor or controllable silicon, organize what is called " chopper " circuit of electronic switch, the control on/off is adjusted duty ratio, reduces the time of start-up course electric current by the main winding circuit, reaches the purpose that reduces starting current.

Description of drawings:

Fig. 1 is the circuit theory diagrams of common capacitor start single-phase motor;

Fig. 2 is to use the changeover contact of special centrifugal switch, the circuit theory diagrams of connection or short circuit motor main winding current limliting assembly.

Fig. 3 is to use the changeover contact of special centrifugal switch, the circuit theory diagrams of control main winding part bridging coil break-make.

Fig. 4 is the comprehensive circuit theory diagrams that use multi-thread winding in parallel and current limliting assembly.

Fig. 5 is to use chopper circuit, and restriction start-up course electric current is by the circuit structure schematic diagram of main winding time.

The unified numbering of each map logo is as follows:

Z is a main winding, and Z2 is the multi-thread and rich main winding bridging coil of coupling part not when starting; QC is for starting capacitor; F is an auxiliary winding; K is common centrifugal switch; TK is special centrifugal switch; QR is the whole sign of current limliting assembly that is not limited to simple resistor; Other sign will be introduced in following embodiment.

Embodiment: further introduce execution mode of the present utility model below in conjunction with accompanying drawing.

Embodiment one: the monophase machine that comprehensive current-limiting circuit starts

QR is simple current-limiting resistance in Fig. 4 circuit; Z and Z2 be multi-thread and around the motor main winding.In the electric motor starting process, the moving disconnecting point of TK is communicated with startup electric capacity QC and auxiliary winding circuit, the series circuit energized of main winding Z and QR; The equivalent reactance of main winding Z increases (pressure drop that causes because of the very little resistance of QR can be ignored) near the TK responsiveness time along with the continuous increase of rotating speed; After centrifugal switch TK action breaks away from the path that starts electric capacity, connect the not bridging coil Z2 of coupling part of main winding simultaneously, and the series resistance QR of short circuit coil Z, the normally circuit of operation formed.Calculate and test repeatedly the resistance of total sectional area and the series resistance QR of coil Z meticulously, can on the basis that guarantees best starting characteristic, strive for the effect that limiting starting current is best.

Embodiment two: chopper control system starting current is by the monophase machine of main winding time.

Centrifugal switch TK special in Fig. 5 circuit is communicated with startup electric capacity QC and auxiliary winding loop in start-up course, the comprehensive current-limiting circuit of motor main winding chopper on the left side in figure is communicated with power supply, after the approaching specified running speed of rotating speed, because of centrifugal switch TK action comprehensive current-limiting circuit of short circuit chopper after disconnecting the auxiliary winding circuit, the motor main winding directly is communicated with power supply and enters normal operation.

In the comprehensive current-limiting circuit of chopper, continued flow resistance R1 and string have high power transistor (or the NMOS pipe) BG1 of resistance R 2 to constitute the current-limited startup circuit of bearing electric current in turn; BG1 is subjected to the front stage circuits Control work on off state, and electric current mainly flows through the very little resistance R of resistance 2 during conducting, then keeps electric current than small component by continued flow resistance R1 between the off period.

Current-limiting resistance R3, rectifying tube D1, voltage-stabiliser tube WY and capacitor C 1 provide the voltage of the metastable work of chopper control circuit; Time-base integrated circuit 555 combines the oscillator that constitutes common EDM Generator of Adjustable Duty Ratio with R4, RW, R5, D 2, D3 and capacitor C 2, the output high level is through resistance R 6 driving power pipe BG1 saturation conductions, and motor main winding loop forms power path through series resistance R2; Electric current is kept by the bigger continued flow resistance R1 of resistance in motor main winding loop between the power tube BG1 off period.Resistance R 7, R8, R9 and transistor BG2 be in conjunction with forming the high-voltage and current-limitation circuit, voltage the highest during drag down the level of time-base integrated circuit 5 pin, BG2 is because of can't conducting limiting the protection of passing through to obtain limiting maximum current of maximum current.

In the main power consumption component of this circuit: power tube BG1 works on off state; Super-high-current was selected very little resistance when resistance R 2 started initial (or stall) for restriction, and avoided the electric current peak because of the high-voltage and current-limitation circuit function; The less electric current of continued flow resistance R1 restricted passage and during the power tube saturation conduction by resistance R 2 shunting in parallel, calculate the data of selecting meticulously the each several part power consumption all be limited in less numerical value, can be directly installed in the space of motor fan housing.

Claims

1. monophase machine from the tape starting current-limiting apparatus is characterized in that: the centrifugal switch of break contact changes into possesses the moving centrifugal change over switch that closes with moving disconnected transfer contact simultaneously; In start-up course series connection current limliting assembly or disconnection and around the part bridging coil of main winding; Normal operation disconnects auxiliary winding and starts electric capacity, short circuit current limliting assembly or connection main winding remainder.

2. according to the described monophase machine from the tape starting current-limiting apparatus of claim 1, it is characterized in that: the current limliting assembly uses triode, field effect transistor or controllable silicon to organize " chopper " circuit of electronic switch.