Instruments & Measurements

A galvanometer with a 20 ohms coil resistance has a full scale deflection of 10 mA. A 0.02 ohm is placed across the meter to increase its rated capacity. What is the new full scale current for the meter?

A 200:5 current transformer is used with a 10 amps ammeter. If the meter reads 4.5 amps, determine the line current.

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

The input power to a 3-phase induction motor running without load is measured by the two wattmeter method. One wattmeter indicates −220 watts and the other indicates 940 watts. What is the no-load power factor of the motor?

A sinusoidal current having peak value 7.07 A is superimposed on dc of 5 A. If a hot-wire ammeter is used to measure the combined current in the circuit, it will indicate ___ amperes.

A meter has a full-scale current of 50 μA. What is its sensitivity?

Power in balance 3-phase system is measured by the two-wattmeter method and it is found that the ratio of the two-wattmeter readings is 2 is to 1. What is the power factor of the system?

What is the total power consumed by the load when the readings of two wattmeters are 5 kW and -0.5kW?

Given a 100 kVA 2,400/240 v single phase transformer. Find the current transformer (CT) ratio at the low voltage side.

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?

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?