CN201118488Y

CN201118488Y - A voltage-reducing start device

Info

Publication number: CN201118488Y
Application number: CNU200720075791XU
Authority: CN
Inventors: 朱荣建; 李蔡慎
Original assignee: Shanghai Ultra-HV Transmission and Distribution Company Shanghai Electric Power C
Current assignee: Shanghai Municipal Electric Power Co
Priority date: 2007-11-21
Filing date: 2007-11-21
Publication date: 2008-09-17
Anticipated expiration: 2017-11-21

Abstract

A step-down starting device comprises a common self-coupling step-down starting circuit and is characterized in that the starting device also comprises a time base delay circuit; the normally closed contact of a contactor KM3 and the normally open contact of a contactor KM1 of the time base delay circuit are respectively connected to the two primary ends of a power transformer T; the normally closed contact of a relay K1 is connected in the power loops of the middle relays KM1 and KM2 in series to switch off a starting loop when a switching loop fails. The step-down starting device of the utility model has an additional time base delay circuit based on the original circuit to cut off the starting loop when the step-down starting device can not complete the switching work in a limited time so as to prevent an autotransformer being burnt and send a warning signal to inform the staff on duty, at the same time.

Description

A kind of reduced-voltage starting device

Technical field

The utility model relates to a kind of reduced-voltage starting device of electrical equipment, relates to a kind of reduced-voltage starting device of motor more specifically.

Background technology

The automaticity of transformer station's control appliance requirement at present is more and more higher, has required to realize complete unattended operation at the control scene.Therefore, the reliability of all kinds of motor start-up control appliances and fail safe seem very important.In start-up course,, require the above high power motor of 15KW must adopt the reduced-voltage starting mode for reducing influence to electrical network and contiguous electric equipment.The reduced-voltage starting cabinet has become one of indispensable important corollary equipment in the electric motor control device.In the station there be reduced-voltage starting mode commonly used at present: autotransformer reduced-voltage starting and star-delta reduced-voltage starting.The common ground of this dual mode all is to adopt the time relay, and motor is switched the band normal operation.In reality is switched, often break down because of the time relay or circuit switched, make the reduced-voltage starting device in the limited time, not finish switch operating, thereby motor is in subnormal voltage operation for a long time.If surpass still not switch the start-up time of regulation autotransformer will be burnt, the serious consequence that causes motor to burn at last.We analyze the incident that generation autotransformer and contactor in transformer station's reduced-voltage starting process together burn, and propose a kind of improvement start-up circuit suggestion.It is simple to improve one's methods, and cost is low, has higher use value.

The utility model content

For addressing the above problem, the utility model provides a kind of novel reduced-voltage starting device, and this device has a protective device, in the time of can't automatically switching to atmospheric pressure state behind the motor reduced-voltage starting, cuts off start-up circuit automatically, sends alarm signal.

For finishing above-mentioned task, reduced-voltage starting device of the present utility model adopts following technical scheme:

A kind of reduced-voltage starting device, comprise self coupling reduced-voltage starting circuit, it is characterized in that, base delay circuit when also comprising, the normally-closed contact of the contactor KM3 of time base delay circuit and contactor KM1 normally opened contact are connected the elementary two ends of power transformer T respectively, the normally-closed contact of relay K 1 is serially connected with in auxiliary relay KM1, the KM2 electric power loop, when switching circuit breaks down, cuts off the startup loop.

Wherein, the normally opened contact of the relay K 1 of time base delay circuit is connected in parallel between the normally opened contact of auxiliary relay KM5 of alarm circuit, when switching circuit breaks down, connects the controlling alarm loop, sends alarm signal.

Base delay circuit when reduced-voltage starting device of the present utility model increases on the basis of primary circuit when the reduced-voltage starting device can not be finished switch operating in the limited time, in time cuts off the startup loop, avoids autotransformer to burn; Send alarm signal simultaneously and notify the operator on duty.

Description of drawings

Fig. 1 is the circuit theory diagrams of reduced-voltage starting device of the present utility model.

Embodiment

Below in conjunction with the drawings and specific embodiments a kind of reduced-voltage starting device of the present utility model is further described.

As shown in Figure 1, its underpart is self coupling reduced-voltage starting manipulated or operated apparatus commonly used, and its course of work is that the air switch QS that closes gets to " automatically " position with change over switch SA.Click startup SB1, contactor KM1 gets electronic work, and normally opened contact and normally opened contact KM1 are closed simultaneously, contactor KM2 gets electronic work, and normally opened contact KM2 closure keeps and interlocking KM1, KM2, normally opened contact KM2 closure, motor M obtains starting resistor by autotransformer T1 step-down.Meanwhile, another normally opened contact of KM2 is connected, and time relay KT gets electric, and its normally opened contact KT is through timing closing, and it is electric that auxiliary relay KM4 is got, thereby connects the power supply of running major loop contactor KM3, and disconnects startup loop contactor KM1, KM2.If but this moment, time relay KT was failure to actuate because of certain reason breaks down, or its time-delay normally opened contact loose contact, auxiliary relay KM4 can not in finite time, in time be connected.Then motor M is in starting state for a long time.Because the starting current of motor is 4-7 times of rated operational current, this electric current also flows through autotransformer.Start-up time is long more, and the temperature rise of autotransformer is high more, finally causes burning out.

As shown in Figure 1, a kind of reduced-voltage starting device of the present utility model has increased by a protective circuit on the basis of the self coupling reduced-voltage starting of prior art.

Protective circuit is by the IC in the accompanying drawing (time-base integrated circuit NE555), and relay K 1 constitutes with relevant accessory circuit.Contactor KM3 normally-closed contact and KM1 normally opened contact are connected the elementary two ends of power transformer T respectively, and the normally-closed contact of relay K 1 is serially connected with in auxiliary relay KM1, the KM2 electric power loop, and its effect is when switching circuit breaks down, and cut off to start the loop.The normally opened contact of relay K 1 is connected in parallel between the normally opened contact of auxiliary relay KM5 of alarm circuit, and its effect is when switching circuit breaks down, and connects the controlling alarm loop, sends alarm signal.

Start-up course is pressed start button SB1 as previously mentioned, contactor KM1, KM2 in succession electric adhesive, the closed motor M power supply of connecting of its normally opened contact, motor is through the autotransformer reduced-voltage starting; The closed energized transformer of another normally opened contact T of KM1, power supply is exported the 12V direct voltages with three-terminal voltage-stabilizing integrated package 7812, and this voltage charges to capacitor C 3 by resistance R.If this moment, time relay KT or its circuit switched broke down, then the KM1 normally opened contact continues to remain closed, and C3 continues charging.Still can not switch to normal operation when surpassing 2 times of regulation start-up times; then IC 6., 2. the pin current potential rises to and is higher than or value level 2/3VCC; IC is the pin output low level 3.; relay K 1 adhesive; its normally-closed contact K1 disconnects contactor KM1, KM2 power supply, realizes automatic switching protection thereby cut off the motor start-up ring current.The closed auxiliary relay KM5 that connects of another normally opened contact of K1.The warning circuit relevant by the KM5 contacting sends warning.Because of the KM5 adhesive keeps, warning will be sustained, and get rid of up to fault.Various ways such as the optional warning lamp of alarm signal, alarm song, electric bell and telephone dialing.

As it is normal to start commutation circuit, and then KM4 is connected in KT timing closing, connects KM3 then, and the KM3 main contacts is being connected major loop simultaneously, and the power supply of its normally-closed contact deenergization transformer T is deactivated protective circuit when motor runs well.

Power transformer T will use 380V/15V, 5W miniature transformer, the control transformer in the also available reduced-voltage starting cabinet.Relay K 1 adopts the 12V direct current relay.Computing formula is T=1.1R*C3; As 50 seconds start-up times, the protection time-delay should be set at 100 seconds.

This circuit debugging is the outage engine loads earlier, and simulation KT breaks down, and is pressing start button, and after surpassing 2 times of start-up times, K1 answers action message in time to disconnect KM1, KM2 power control loop.After initial adjustment finishes, be with motor load to do last debugging again, can devote oneself to work.

, but should be understood that under the situation that does not break away from relevant protection range defined by the claims that those skilled in the art can make change and/or revise according to embodiment of the present utility model describing the present invention property and nonrestrictive description.

Claims

1, a kind of reduced-voltage starting device, comprise self coupling reduced-voltage starting circuit, it is characterized in that, base delay circuit when also comprising, the normally-closed contact of the contactor (KM3) of time base delay circuit and contactor (KM1) normally opened contact are connected the elementary two ends of power transformer (T) respectively, the normally-closed contact of relay (K1) is serially connected with in auxiliary relay (KM1), (KM2) electric power loop, when switching circuit breaks down, cuts off the startup loop.

2, reduced-voltage starting device according to claim 1, it is characterized in that the normally opened contact of the relay (K1) of time base delay circuit is connected in parallel between the normally opened contact of auxiliary relay (KM5) of alarm circuit, when switching circuit breaks down, connect the controlling alarm loop, send alarm signal.