Instruments & Measurements

A moving coil instrument requires 50 mA and 100 mV for full-scale deflection. What is the value of the shunt required to convert it to read up to 5 A?

A dc ammeter has an internal resistance of 0.1 Ω. A shunt of \(1.01 \times 10^{-3}\) Ω is connected to the ammeter. What is the multiplier of the set up?

By using two wattmeter method, power can be measured in

The ratio of the wattmeter readings in three-phase inductive system is 2:1 when power is measured by the two-wattmeter method. What is the power factor of the load?

At a 115 kV substation, the PT ratio is 1,000 and the CT ratio is 1200/5. The potential going into the wattmeter is 115 volts. What is the MW indicated when the wattmeter reads 800 watts?

A dc ammeter has an internal resistance of 0.1 Ω. A shunt of \(1.01 \times 10^{-3}\) Ω is connected to the ammeter. What is the multiplier of the set up?

When using an ohmmeter, disconnect the applied voltage from the circuit being checked. Why?

A megger is basically what type of an instrument?

Hot wire instruments are using which type of scale?

Which of the following damping methods is common in moving coil instruments?

What will happen to the needle of an ohmmeter when an open capacitor is connected across its terminals?

Shunts in ammeter are made from which of the following materials?

In a two-wattmeter method, the algebraic sum of the readings of two wattmeters will indicate true power if.

How many wattmeters are needed to measure the unbalanced power of a three-phase system?

What is the minimum number of wattmeters required in measuring the power consumed by a balanced three-phase loads?

In order to measure power in a 3-phase, 4-wire unbalanced load, determine the number of wattmeters needed?

What is the reason why “three-wattmeter method” is not normally used to measure power in a three-phase circuit?

Before removing the ammeter from a current transformer, its secondary must be short circuited in order to avoid which of the following?

What is the reason why the scale of a permanent magnet coil instrument is uniform?

An oscilloscope is largely used to measure which one?