UNIVERSAL CURRENT SENSORS

INTRODUCTION MEASUREMENT OF ELECTRIC CURRENT STRENGHT IS DIFFICULT FOR ELECTRONIC CONDITIONING CONNECTING AMMETER AND READING OUT VALUES ARE NOT VALID GALVANIC ISOLATION AND BAND WIDTH PHYSICALLY LARGE AND TECHNICALLY COMPLEX

SENSORS IMPORTANCE OF SENSORS * CURRENT IS FED TO COMPUTERS IN WHICH SENSORS CONVERT IT TO PREPOTIONAL VOLTAGE * MINIMUM INFLUENCE ON MEASURED CIRCUT

EARLIER SOLUTIONS 1. TO MEASURE VOLTAGE DROP ACROSS RESISTOR PLACED IN CURRENT PATH USE A TRANSFORMER HALL CURRENT SENSORS

CONSTRUCTION AND TYPE OF HALL SENSORS CIRCULAR CORE OF SOFT MAGNETIC MATERIAL HALL ELEMENT TO PRODUCE PREPOTIONATE VOLTAGE AMPLIFIER TYPES OPEN LOOP AND CLOSED LOOP

COMPARISON OF OPEN LOOP AND CLOSED LOOP SENSORS AMPLIFIED OUTPUT OF HALL ELEMENT IS DIRECTLY USED AS MEASURED VALUE PRICE AND SENSITIVITY IS LOW CLOSED LOOP A COMPENSATION COIL IS WOUND AROUND MAGNETIC CORE NON LINEARITY AND TEMPERATURE DEPENDANCE ARE REDUCED NOT CHEAP AND BULKY FOR HIGH CURRENTS

HALL CURRENT SENSORS

MAGNETO RESISTIVE EFFECT SLIGHT CHANGES IN RESISTANCE WHEN FERRO MAGNETIC MATERIALS ARE PLACED IN MAGNETIC FIELD A PREFFERD ORIENTATION OF MAGNETISATION WHEN EXPOSED TO MAGNETIC FIELD MAGNETIC MOMENT ALONG LINEAR AXIS COULD BE CHANGED BY APPLYING MAGNETIC FIELD WHICH RESULT IN INCREASE IN CURRENT

RESISTANCE DEPEND ON ANGLE U BETWEEN DIRECTION OF MAGNETISATON M AND CURRENT GOING THROUGH IT CHANGE IN RESISTIVITY dr/r PREPOTIONAL TO COS 2U MAXIMUM SENSITIVITY AT 45

BARBER POLE CONFIGURATION IS OBTAINED BY PLACING ALUMINIUM CONDUCTORS AT AN ANGLE < 45

ADVANTAGES OF MAGNETO RESISTORS CONFIGURED AS WHEATSTONE BRIDGE USED AT HIGH FREQUANCY USED AT HIGH TEMPERATURE HIGH SENSITIVITY

CONSTRUCTION CONFIGURED AS FULL BRIDGE WITH BABER POLES PLACED IN OPPOSITE DIRECTION TO IMPROVE TEMPERATURE DEPENDANCE ELECTRICALLY ISOLATED ALUMINIUM COMPENSATION CONDUCTORS ARE USED ON SAME SUBSTRATE ABOVE PERMALLOY RESISTORS TO IMPROVE LINEARITY VOLTAGE DROP ACROSS RESISTOR FORMS ELECTRICAL OUTPUT SIGNAL PRIMARY CONDUCTORIS U SHAPED

USE CREAMIC SUBSTATE ONTO WHICH PRIMARY CONDUCTOR IS GLUED

FEATURES 1. NO MAGNETIC SHIELDING NEEDED 2. LINEARITY ERROR<.1% OFFSET VOLTAGE<10MV 3.POWERED BY STANDARD BIPOLAR VOLTAGE OF +OR- 15 4. POWER CONSUMPTION IS 320MWTO 640MW 5.NO REMANENENCE

OUTPUT CAN BE SCALED FOR A/D CONVERTERS COMPARATOR TO MEASURE SHORTCIRCUIT CURRENT NO REMANENCE DUE TO ABSENSE OF CORE COMPESATION PRODUCE HIGH LINEARITY

ADVANTAGES SMALLER VOLUME AND WEIGHT COMPARED TO CONVENTIONAL CURRENT SENSOR NO REMANENCE IN THE EVENT OF OVERLOAD MEASUREMENT OF DC AND AC CURRENT WITH OUT ADDITIONAL LOSSES WIDE FREQUANCY RANGE LOW SYSTEM COST

APPLICATION INVERTERS AND SERVO REGULATORS ENERGY DISTRIBUTION POWER ELECTRONICS SYSTEM BATTERY MANAGEMENT UNINTERRUPTABLE POWER SUPPLIES ROBOTICS AUTOMOTIVE

RECENT DEVELOPEMENTS SENSOR MODULE IS REALISED AS DIL CHIP MOUNTED ON POWER PCB BOARD BUS BAR IS ALIGNED AS BUS BAR PLATE

LATEST MR SENSORS PRIMARY CONDUCTOR IS USUALLY FLAT SENSOR MODULE IS CLIPPED INTO A SLOT MADE IN IT SENSORS ARE MOUNTED ON SUBSTRATE AND ENCAPSULATED IN PLASTIC THEY ARE SMALL COMPACT LIGHT CHEAP AND EASY TO MOUNT PRIMARY CONDUCTOR IS PART OF APPLICATION

The latest type of magnetoresistive current sensor is placed into a slot in a straight conductor, in this case a 200 A copper bus bar.

CURRENT SENSORS IN TOMMORROWS CARS MANY COMPONENTS OPERATED BY CARS ENGINE WILL IN FUTURE OPERATE ON ELECTRICITY ACCORDING TO NEW PROTOTYPE PRESENT AT MANNESMANN-SACHS AG AT 1999 IAA CAR EXHIBITION IN GERMANY A STARTER GENERATOR I S USED IT REQUIRE THREE PHASE MOSFET ALTERNATOR 2 PHASES REQUIRE MAGNETO RESISTANCE CURRENT SENSORS

CONCLUSION MAGNETO RESISTIVE SENSORS ARE A GROUP OF SENSORS WHICH HAVE BOUGHT FAST AND REVOLUTIONARY CHANGES IN CURRENT MEASUREMENT AND ITS CONDITIONING . ATTEMPTS ARE GOING ON TO MAKE IT MORE USER FRIENDLY IN THE NEXT FEW DECADES MAGNETO RESISTORS AND ITS SENSORS ARE PREDICTED TO REPLACE THE CONVENTIONAL RESISTORS IN ALL APPLICATION