Join 60,000+ competitive exam aspirants
or with email
Your Cart
SubtotalтВ╣0
TotalтВ╣0
Examoogle тАв User тАв info@examoogle.com тАв EE-2024-8821
Chapter 1 of 12 тАв Page 1 of 248ЁЯФТ Protected PDF тАв Watermarked
Join 60,000+ competitive exam aspirants
The current reverser in the earth tester converts __________.
AC to AC
DC to DC
DC to AC
AC to DC
DC to AC
The current reverser in an earth tester, also known as a commutator, converts direct current (DC) from the internal generator into alternating current (AC). This conversion is necessary because DC currents flowing through the soil can cause electrolytic polarization, which leads to erroneous resistance readings.
IS 1892:1979
The current reverser in an earth tester, also known as a commutator, converts direct current (DC) from the internal generator into alternating current (AC). This conversion is necessary because DC currents flowing through the soil can cause electrolytic polarization, which leads to erroneous resistance readings.
ReтАЛ=IVтАЛ тАФ where ReтАЛ is the earth resistance, V is the voltage, and I is the current through the soil.
The earth tester utilizes a hand-driven generator that produces DC. The current reverser consists of a set of brushes and segments mounted on the shaft of the generator. As the shaft rotates, the mechanical arrangement reverses the direction of current flow into the soil probes, ensuring the earth resistance is measured using AC, thereby eliminating the interference of stray galvanic currents.
Eliminates electrolytic effects in the soil.
Prevents back EMF interference from stray DC currents.
Uses a mechanical commutator mechanism.
Provides a stable reading for earth electrode resistance.
Accurate measurement in presence of stray currents
Independent of lead resistance
Requires manual operation or external drive
Mechanical parts require regular maintenance
Measuring soil resistivity
Testing grounding systems in electrical installations
Option B is incorrect because measuring earth resistance with DC would lead to polarization error.
Option D is incorrect because the internal source is DC and the tester needs to supply AC to the probes.
C is correct тАФ The current reverser converts DC to AC to perform earth resistance testing without polarization errors.
Always remember that in electrical measurements involving soil or electrolytes, AC is preferred to avoid the DC-induced chemical polarization effect.
Get instant step-by-step AI explanations, full shift Previous Year Papers (SSC GD, RRB, SSC JE), and regional rank analysis on the official Examoogle App.
Free Download тАв 100K+ Aspirants