COMPLETE COURSE IN ELECTRICAL MEASUREMENT & INSTRUMENTATION

Understand how measurement errors arise in electrical measurement and instrumentation by defining absolute and relative errors and calculating percentage error from measured and true values.

Identify the two main error types—systematic and random—in electrical measurements, and learn how instrument friction, environmental conditions, zero setting, and averaging readings reduce instrument errors.

Explore the loading effect in electrical measurement by examining how instrument resistance and circuit resistance introduce errors, voltage drops, and altered readings in measurement circuits.

Explore how to compute the percentage error between measured and true resistance values and examine how 1 percent tolerances in resistors affect the equivalent resistance in parallel circuits.

Examine analog meters and their continuous-time behavior, where a pointer and scale display input changes as time advances, showing the corresponding output on the scale for electrical measurement and instrumentation.

Discover the three torques—developing, controlling, and damping—in electrical measurement and instrumentation, and learn how pointer deflection and damping determine accurate readings on a scale.

Explore controlling torque in meters through spring and gravity control, showing how a pointer on a spindle deflects to indicate readings, returns to zero, and reaches equilibrium.

Explore damping systems that reduce pointer vibration with a friction damping air chamber and a piston, and transformer-based damping that induces EMF in an aluminium former to oppose motion.

the PMMC instrument uses a permanent magnet moving coil to deflect a pointer under DC current, serving as ammeter in series or voltmeter in parallel with a uniform scale.

Extend the ammeter range by adding a parallel shunt resistor to carry excess current, keeping the meter coil unaffected while calculating the magnification factor M to reach the desired range.

Extend the voltmeter range by adding a high-value series resistance (orange extension) and use the magnification factor to measure higher voltages.

Explain swamping resistance as a temperature compensating element that keeps coil resistance stable despite temperature changes, maintaining a proportional current and thus reducing measurement error.

Explore the attraction type moving iron instrument, where coil current deflects a soft iron piece and the pointer reads edm and voltmeter. Damping returns the pointer when supply is removed.

The repulsion type moving-iron instrument uses a fixed coil to generate a magnetic field that repels a moving iron element, causing the pointer to rotate and provide the measurement.

Explore the electrodynamometer type instrument, where a movable coil in a magnetic field experiences force, with self and mutual inductance affecting nonlinear, nonuniform scale readings.

Explore how electrostatic instruments measure very high voltages using fixed and moving plates, where charge attraction or repulsion moves a pointer to indicate voltage, current, or power.

explains thermocouple type instrument and electro-thermal instruments, including i^2r heating and pointer deflection, with calibration for current and voltage in both ac and dc systems.

Explore how a dynamo meter type power factor meter measures power factor using resistance and inductance to create a 90-degree current difference and reads leading, lagging, or zero power factor.

A single-cycle synchroscope helps synchronize an incoming generator with an existing 50 Hz system by indicating frequency difference and guiding safe switching.

extend the ammeter's range from 5 A to 25 A. add a 0.05-ohm resistor in parallel with the ammeter to achieve the extended range.

Analyze how current passes through meters and how readings vary with orientation and environment, including minus eight values, in electrical measurement and instrumentation.

Solve a moving coil instrument problem, with 100 turns, a coil size of 1 mm by 20 mm, in a uniform radial flux density, and convert given quantities to units.

Derive the instrument equation and compute the rate of change for a measurement scenario in problem 4, illustrating core techniques in electrical measurement and instrumentation.

Determine the deflection at zero position and the equilibrium condition by applying the given control scrimgeour constant and solving the equation, yielding a deflection of 1.2 radion.

Explore resistance measurement by detailing high, medium, and low resistance ranges (high > 100 kΩ) and the need for range-specific instruments like megger, ohmmeter, and loss-of-charge methods.

Explore how a multimeter measures an unknown resistance by connecting it across two terminals, using a calibrated scale and selectable range to convert current into a reading.

This lecture explains how ammeter and voltmeter arrangements bias resistance readings due to ammeter's internal resistance; it compares high- and low-resistance cases and shows how increasing external resistance reduces error.

Balance the Wheatstone bridge to zero detector current, equating voltages at bridge points and applying Ohm's law to derive the unknown resistance R_x from the voltage and current relationships.

Use the Kelvin double bridge to measure low resistances, cancel lead resistance with a balancing variable resistor, and determine the unknown value X by ratio balancing, like a Wheatstone bridge.

Explore how a megger measures megaohm insulation resistance using a moving-coil setup with permanent magnets, calibrating for coil differences to determine Rx.

Apply the loss of charge method to measure high resistances by charging a capacitor through the unknown resistance and recording the capacitor voltage after a known time to compute resistance.

Identify the objectives of studying ac bridges and calculate unknown inductances and capacitances using a bridge. Understand the dissipation factor and the opposition to changes in current and voltage.

Explore the four-arm bridge and how zero current in the detector signals balance. Derive the balance condition Z1/Z3 equals Z2/Z4 and extend to complex impedance with phase angles.

Explore Maxwell's inductance bridge by balancing and determining the unknown inductance, equating the real and imaginary parts of impedance and adjusting variable quantities.

Explore Maxwell's inductance bridge phasor by examining the impedance diagram, linking currents and voltages with resistance and inductive reactance, and showing how V1 to V4 arise from phasor combinations.

Navigate Maxwell's inductance-capacitance bridge to determine inductances by adjusting a parallel capacitor until balance. Derive the balance condition from impedance ratios and use real and imaginary parts to compute L.

Explore Maxwell's inductance-capacitance bridge phasor, showing how a capacitor causes a 90-degree phasor lead and how the bridge balances so Vp equals Vq, yielding zero detector current.

Explore Hay's bridge for measuring unknown inductance and how it differs from the Maxwell bridge. Derive balance equations by equating real and imaginary parts to calculate L1.

Delve into the Hay's bridge phasor, explaining why the voltage drop across the arm lags due to the capacitor and the role of the resistor and reactance in the bridge.

Use Owen's bridge to determine the unknown inductance L1 by balancing with a known capacitance C1 and adjustable R2, so the detector reads zero and the balance yields L1.

Explore the quality factor of capacitors by contrasting real and ideal capacitors, examining dissipation factor and loss angle, and relate them to energy loss and heat in practical circuits.

Determine unknown capacitance C1 by comparing it with C2 in De-Sauty's bridge, balancing resistors R3 and R4, and applying phasor analysis to show capacitance lags voltage.

Use the Schering bridge to determine unknown capacitance C1 by balancing the network with known resistances and a variable capacitor, and learn its loss angle and dissipation factor.

Explore Wien's bridge for frequency measurement, as an oscillator, and signal analysis, deriving the frequency expression from the balanced equation with R1, R2, C1, and C2.

Analyze a Wheatstone bridge with 300-ohm arms, balance conditions, and a 1% resistance change, showing zero current through the galvanometer and the resulting output voltage.

The lecture guides solving problem 2 by manipulating the denominator, multiplying by minus the square, and comparing the real and other parts to reach the final expression.

Determine the impedance z in an electrical measurement and instrumentation context using a balanced bridge by equating the real and imaginary parts to read z as 260 ohms.

Balance a resistive bridge by sequentially adjusting R1, R2, R3, and R4 so the meter reads zero, deriving the balance condition and related expressions in terms of Q.

Examine how to read a voltmeter in a bridge circuit by analyzing open-circuit conditions and series LC drops to determine the balance and the meter reading VE minus VB.

Balance the impedance of the capacitor network with losses by converting capacitors to impedance using z = 1/(ω c) and solve for c1 in terms of c2.

Instrument transformers, including current and potential transformers, enable accurate metering, protection, and prediction by using turns ratios and calibration while reducing meter size and cost.

Learn about special instrument transformers like indoor current transformers, high-voltage bushing types, and clamp-on meters, which measure line current and step down voltages for safe metering.

Explore the phasor diagram and the equivalent circuit of an instrument transformer, examining primary and secondary resistances and reactances, magnetizing current, losses, and referred currents.

the lecture explains how instrument transformer ratio is affected by extra components, causing calibration problems and ratio errors that skew secondary values and power measurements.

Increase the cross-sectional area and use high permeability materials to lower flux density and reduce instrument transformer errors. Improve winding coupling to minimize leakage flux.

Explain how the secondary burden on current and potential transformers represents the load that causes voltage drop and volt-ampere (va) requirements for accurate metering.

Learn how wattmeters measure electrical power by distinguishing real, reactive, and apparent power, using voltage, current, and phase angle to form the power triangle and P=VI cos φ.

Blondel's theorem states that in a three-phase system the total power equals the sum of the three wattmeter readings. Connect each wattmeter between a line and neutral to obtain W1+W2+W3.

Learn to apply the two-wattmeter method for measuring power in three-phase systems, including w1 and w2 readings, phasor diagrams, and balanced or unbalanced loads with power factor considerations.

Examine errors in wattmeters using electro dynamo type instruments, including inductive errors, coil losses, external magnetic fields, resonance, temperature effects, and compensation with capacitors and compensating coils.

Explore how reactive power is measured and calculated with a wattmeter, detailing the voltage–current angle, sign conventions, and circuit connections to obtain reactive power values.

Identify how third and fifth harmonics distort wattmeter readings by altering the fundamental frequency and phase relationships, and determine meter readings when harmonic currents and impedances are present.

Explore the role of energy meters in domestic and industrial use, their analog working principles, the various types, active and reactive power, and tracking energy consumption for billing.

Understand how energy meters operate: rotating disc driven by flux interactions from shunt and series magnets generates torque, enabling reading through the window.

Explore how the energymeter uses phasor relationships between supply voltage and current, with series and shunt flux, induced emf, and eddy currents shaping impedance and phase angle.

Explore phase angle error in energy metering, from the phasor diagram to voltage–current differences, showing energy calculation via power integration and the claim that 90-degree phase yields accurate readings.

Use adjustable resistance to shift phasors, making the voltage–current angle 90 degrees for accurate power measurement. An adjustable shunt coil provides extra flux, with resistance controlling current and flux.

Explore the copper shading band technique to adjust flux and shift the voltage–phase angle toward 90 degrees in energy meter, by moving the band up or down to vary current.

Friction compensation in energy meters uses a vane to create flux and eddy currents that generate additional torque, overcoming disk friction and ensuring accurate energy measurement.

Explore creeping in energy meters, where no-load operation rotates the disc due to overcompensation and friction, and learn remedies using two opposite poles and a brick magnet to stop rotation.

Explore phantom loading to test energy meters by using fictitious loads from parallel voltage and current sources, achieving rated voltage and current without wasting energy.

Determine the meter constant by converting the energy consumed at 450 W for 100 s into kilowatt-hours and finding revolutions per kilowatt-hour, resulting in 800 rev/kWh.

Calculate energy consumption by converting revolutions to kilowatt hours using the meter constant, compare measured 545.45 revolutions per kWh to the rated 550, and compute a 0.2% error.

Analyze energy consumption using an energy meter, calculate kilowatt-hours for a two-hour test, and compare loading and phantom loading conditions to highlight energy savings.

Calculate the meter constant as 400 revolutions per kilowatt hour from a six-hour energy test, then verify with a 230-volt, five-hour case showing 1712 revolutions aligns with the same constant.