250+ TOP MCQs on Lag Adjustment Devices and Answers

Electrical Measurements & Measuring Instruments Multiple Choice Questions on “Lag Adjustment Devices”.

1. The energy meter always measures the load energy correctly.
a) True
b) False
Answer: b
Clarification: When the difference in phase angles between the shunt magnetic flux and the applied voltage is 90 degrees (lagging), the reading of the load energy obtained from an energy meter is correct.

2. Obtaining correct reading from the energy meter requires ______________
a) low resistance and iron losses
b) high resistance and iron losses
c) high resistance and low iron losses
d) low resistance and high iron losses
Answer: a
Clarification: In order to obtain an exact reading for the energy consumed by a load using an energy meter, we require the pressure coil to have a low value of resistance and low iron losses.

3. Phase angle can be made 90 degrees using ____________
a) lead circuit
b) lag circuit
c) special design
d) transformer
Answer: c
Clarification: Phase angle in an energy meter can be made approximately 90 degrees by making use of a special design in the energy meter.

4. Shading coil consists of many thick turns.
a) True
b) False
Answer: b
Clarification: On the central limb of a shunt magnet we can make use of a shading coil. The shading coil consists of a few fairly thick turns. The figure below shows a shading coil on the central limb of the shunt magnet.