Hariharan Foundations Interview Questions and Answers

RCCB stands for Residual Current Circuit Breaker. It is an electrical safety device used to protect against electric shock.

• RCCB is installed in the electrical distribution board.

• It detects and quickly interrupts the circuit if there is a leakage current.

• To work on RCCB, follow these steps:

• 1. Ensure the power supply is switched off.

• 2. Open the electrical panel and locate the RCCB.

• 3. Check for any visible damage or loose...read more

Ohm's Law states that the current flowing through a conductor is directly proportional to the voltage across it and inversely proportional to its resistance.

• Ohm's Law relates the three fundamental electrical quantities: current, voltage, and resistance.

• The equation for Ohm's Law is I = V/R, where I is the current, V is the voltage, and R is the resistance.

• This law helps in understanding and calculating the behavior of ...read more

Induction motors work on the principle of electromagnetic induction to convert electrical energy into mechanical energy.

• Induction motors have a stator and a rotor.

• When an alternating current is supplied to the stator windings, a rotating magnetic field is created.

• This rotating magnetic field induces currents in the rotor windings, which in turn creates a magnetic field.

• The interaction between the stator and rotor magne...read more

Phase to phase voltage is the voltage between two phases in a three-phase electrical system.

• Phase to phase voltage is used in three-phase electrical systems.

• It is the voltage between two phases, such as phase A to phase B or phase B to phase C.

• The phase to phase voltage is typically higher than the phase to neutral voltage.

• In a balanced three-phase system, the phase to phase voltage is equal to the square root of 3 tim...read more

The phase to neutral voltage depends on the type of electrical system being used.

• In a single-phase system, the phase to neutral voltage is equal to the line voltage.

• In a three-phase system, the phase to neutral voltage is equal to the line voltage divided by the square root of 3.

• For example, in a 120V single-phase system, the phase to neutral voltage is 120V.

• In a 208V three-phase system, the phase to neutral voltage is...read more

Neutral to Earth voltage is the potential difference between the neutral wire and the earth.

• Neutral to Earth voltage is typically very low, ideally close to zero.

• It is important to maintain a low Neutral to Earth voltage to ensure electrical safety.

• Neutral to Earth voltage can be measured using a voltmeter.

• If the Neutral to Earth voltage is high, it may indicate a fault in the electrical system.

• Neutral to Earth voltage...read more

Calculate the shuttering quantity for a tank of dimensions 10m x 5m x 8m.

• Shuttering is required for the walls and base of the tank.

• Calculate the surface area of the walls: 2*(length + width)*height.

• For this tank: 2*(10m + 5m)*8m = 240m² for walls.

• Add the base area: length * width = 10m * 5m = 50m².

• Total shuttering required = 240m² + 50m² = 290m².

Calculate plastering quantity for a 3m x 3m room with a slab, considering wall and ceiling areas.

• Room dimensions: 3m x 3m, height assumed as 3m for calculation.

• Wall area = 2*(length + width)*height = 2*(3 + 3)*3 = 36 m².

• Ceiling area = length * width = 3 * 3 = 9 m².

• Total plastering area = wall area + ceiling area = 36 + 9 = 45 m².

• Consider plaster thickness and wastage (typically 10%) for final quantity.