Measurement and Instrumentation

Ammeter Shunt is used for the measurement of heavy current using an Ammeter. Ammeter Shunt is basically a low resistance connected in parallel with the moving coil so that most of the current is bypassed by the Shunt and hence only a small current flows through the moving coil. Why ...
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A Capacitor is a device which has the capability to store energy in its Electric Field. Therefore we can say that a Capacitor can store charge. There are many types of Capacitor but the most basic Capacitor is Parallel Plate Capacitor. We will consider this basic capacitor for getting idea ...
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In a capacitor, we always have a Displacement Current and never a Conduction Current under normal conditions i.e. when we apply a potential difference across a Capacitor which is below its specified maximum Voltage. Conduction Currents flow when electrons actually move. But in Displacement Current, no charge carriers are involved ...
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Core Balance Current Transformer or CBCT is a ring type current transformer through center of which a three core cable or three single core cables of three phase system passes. This type of current transformer is normally used for earth fault protection for low and medium voltage system. A typical ...
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Current Transformer Thermal Rating Factor is a number by which the primary load current of CT may be increased  over its nameplate rating without exceeding the allowable temperature rise. Thus thermal rating factor is nothing but the overload capacity of current transformer. Normally thermal rating factor is specified in conjunction ...
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Current Transformer (CT) and Potential Transformer (PT) are instrument transformers basically used for measurement and protection purpose in power systems. A Current Transformer (CT) is used to obtain reduced current signals for purpose of measurement, control and protection. They reduce the higher current to lower values which are suitable for ...
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Electrodynamometer wattmeter and Low Power Factor (LPF) wattmeters are mostly similar in construction and operation, except for the following modifications are carried out in the electrodynamometer wattmeter to convert it into a LPF wattmeter: Pressure coil resistance is kept low to increase the torque. Compensating coil is used to compensate ...
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There are basically three types of energy meters:Electromechanical Energy Meter:The electromechanical induction meter operates by counting the revolutions of a non-magnetic, but electrically conductive, metal disc which is made to rotate at a speed proportional to the power passing through the meter. The number of revolutions is thus proportional to ...
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First question which strikes in our mind is that why do we need to do DCRM even though we already had Contact Resistance Measurement,CRM? Seems good question and this question will take you to the depth.So, first of all we need to know about the contacts of Circuit Breaker. Basically, ...
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Electrodynamic types of instrument are used for the measurement of AC and DC quantities unlike PMMC instrument which can only be used for the measurement of DC quantity. This type of instrument is known as Elctrodynamometer type instrument. Construction of Electrodynamic Type Instrument An electrodynamic type instrument consists of Two ...
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Electrodynamometer Wattmeter are often used for the measurement of power consumption. The construction of such instrument similar to the construction of electrodynamometer type ammeter and voltmeter. An electrodynamometer wattmeter have two types of coils. One coil is fixed and another coil is moving. The fixed coil is connected in series ...
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A capacitor is a device for storing charge. It is usually made up of two plates separated by a thin insulating material known as the dielectric. One plate of the capacitor is positively charged, while the other has negative charge.The charge stored in a capacitor is proportional to the potential ...
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Megger is an electrical device which is used to measure the Insulation Resistance by performing Insulation Resistance Test (IR Test). Basically Megger injects High DC Voltage across the Insulator and ground due to which leakage current flows through the Insulator to the ground. By measuring this Leakage Current, Megger calculates ...
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Ideally the resistance of a Voltmeter is infinite so that so that voltmeter does not alter circuit current. A low resistance voltmeter may give correct reading when measuring voltage in low resistance circuit but the Voltmeter produces unreliable and erroneous reading when connected in high resistance circuit. This is because, ...
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We will discuss how to measure Capacitance and Dissipation Factor. Capacitance is measured by using Schering Bridge. What is this Schering Bridge? First we will discuss how to balance a bridge.As we know for balanced bridge, there should not be any current through the detector which means the potential difference ...
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