CN2137408Y

CN2137408Y - Power-saving unit for asynchronous motor

Info

Publication number: CN2137408Y
Application number: CN 92232533
Authority: CN
Inventors: 黄河清
Original assignee: Individual
Current assignee: Individual
Priority date: 1992-09-08
Filing date: 1992-09-08
Publication date: 1993-06-30
Anticipated expiration: 2002-09-08

Abstract

The utility model relates to a power-saving unit for an asynchronous motor, comprising a casing, a panel, a reactive power compensating circuit and a temperature control circuit. The compensating power factor can reach to 0.96-99; an electrical inductance is connected in series with a compensating capacitor; the starting surge current of the motor is reduced to 5 times of the rated operating current; the pollution of electric network from harmonic wave from is suppressed; the electricity is saved; the safe operation of the motor can be ensured; the utility model is suitable for the motors being away from a transformer, such as a water pump motor, an oil pump electrical machinery on oilfield, etc.

Description

Power-saving unit for asynchronous motor

The utility model relates to a kind of motor electricity saving device, particularly relates to a kind of asynchronous motor battery saving arrangement.

The starting current of asynchronous motor is very big, is 7～8 times of rated operational current, and motor easily burns, power consumption is high, and is energy-conservation for accomplishing, often adopts reduced voltage starting, fall-back is though can receive certain energy-saving effect like this, the equipment needed thereby complexity, the cost height, fault is many, for the motor away from the operation of transformer separate unit, adopts in the high-pressure side or the concentrated reactive power compensation of low-pressure side more, but effect is bad, and the grid power waste is still serious.

The purpose of this utility model is, provide a kind of to society and adopt compensating circuit in asynchronous motor switch-box nearby, carries out reactive power compensation on the spot, and cost is low, manufactures to be easy to the asynchronous motor battery saving arrangement.

The utility model can be realized with following mode:

The battery saving arrangement that comprises casing, panel, reactive power compensation circuit and temperature control circuit, its reactive power compensation circuit are every through inductance L in the end of incoming cables of motor three phase mains ₁, L ₂, L ₃Capacitor group C with delta connection ₁Three summits link to each other the capacitor group C of another group delta connection ₂Normally opened contact 2C and capacitor group C through A.C. contactor ₁Parallel connection, capacitor group C ₂Each capacitor on bulb XD in parallel ₆, XD ₇, XD ₈

Inductance L ₁, L ₂, L ₃Induction reactance be capacitor group C ₁, C ₂2～6% of capacitive reactance.

Advantage of the present utility model:

Compensating circuit is directly installed in the other switch-box of motor, and the local compensation power factor can reach 0.96～0.99, but direct saving power consumption reaches 30%, and the burden of so corresponding power transformer alleviates 20%, and line loss also reduces greatly, seals in inductance L ₁, L ₂, L ₃Can shove the starting of motor and be reduced to 5 times of rated operational current, starting torque and voltage stability all are improved, inductance L ₁, L ₂, L ₃Access, be enough to suppress the pollution of high order harmonic component to electrical network, the temperature control circuit in the motor power supply circuits in addition can prevent motor effectively owing to cross cause thermal damage.

Fig. 1 is that the utility model machine shell panel is arranged schematic diagram;

Fig. 2 is the utility model electrical schematic diagram (reduced voltage starting partly omits).

The utility model is described in further detail below in conjunction with accompanying drawing:

As shown in Figure 1, connect inductance L respectively at the end of incoming cables of motor M three-phase ₁, L ₂, L ₃, inductance L ₁, L ₂, L ₃The other end respectively with the capacitor group C of delta connection ₁Three summits link to each other the capacitor group C of another group delta connection ₂, three normally opened contacts through the normally opened contact 2C of A.C. contactor are connected in parallel on capacitor group C ₁On, capacitor group C ₂Each capacitor on, incandescent lamp bulb XD respectively in parallel ₆, XD ₇, XD ₈, as capacitor C ₂Discharge resistance, capacitor C ₁Capacity by motor M when unloaded the perception lagging current choose capacitor group C to COS ψ=1 with capacitive current compensation ₂When nominal load, choose, inductance L by the insufficient section that compensates to COS ψ=0.96～0.99 by motor M for capacity ₁, L ₂, L ₃Inductance value be capacitor C by its induction reactance ₁, C ₂2～6% of capacitive reactance is chosen, B, C at the three-phase building-out capacitor are connected to current transformer, three-phase has ammeter Aa, Ab, Ac to show capacitance current respectively, the line current that ammeter A display power supply is arranged at power inleting terminal, power factor meter ψ can directly demonstrate the power rate value, press stop button, motor M outage, capacitor group C ₁Discharge, drive motors M is unloaded to rotate capacitor group C ₂By bulb XD ₆, XD ₇, XD ₈Discharge reaches and shuts down in 30 seconds, is discharged to capacitor group C ₁, capacitor group C ₂Terminal voltage is below 60V, and the motor heat protective circuit is reliably accepted the thermistor R of negative resistance charactertistic in the place of thermal source by being embedded in motor M casing surface energy ₁With potentiometer R ₂Dividing potential drop is for transistor BG ₁Quiescent point, the normally-closed contact of relay J are connected in the motor M power supply circuits, by potentiometer R ₂Adjust to the permission temperature rise of motor M, treat motor M because of after certain reason temperature rise surpasses qualified point, the relay J normally-closed contact disconnects, and the protection motor M is not burnt.

Marking each sequence number among Fig. 1 is followed successively by: 1-casing, 2-panel, 3-line voltmeter, 4-line current table, 5-power-factor meter, 6-change-over switch, 7-capacitor discharge bulb, 8-capacitance current display list, 9-indicator lamp.

Claims

1, a kind of asynchronous motor battery saving arrangement comprises casing, panel, reactive power compensation circuit and temperature control circuit, it is characterized in that: reactive power compensation circuit is in the end of incoming cables of motor three phase mains, and is every through inductance L ₁, L ₂, L ₃Capacitor group C with delta connection ₁Three summits link to each other the capacitor C of another group delta connection ₂Normally opened contact 2C and capacitor group C through A.C. contactor ₁Parallel connection, capacitor group C ₂Each capacitor on bulb XD in parallel ₆, XD ₇, XD ₈

2, battery saving arrangement according to claim 1 is characterized in that: capacitor group C ₁Capacity compensate to COS ψ-1 by motor M when unloaded and select capacitor group C ₂The capacity insufficient section that compensates to COS ψ=0.96～0.99 during by the motor M nominal load choose.

3, battery saving arrangement according to claim 1 is characterized in that: inductance L ₁, L ₂, L ₃Induction reactance be capacitor group C ₁, C ₂2～6% of capacitive reactance.

4, battery saving arrangement according to claim 1 is characterized in that: the transducer thermistor R of temperature control circuit ₁It is negative resistance.