Quiz 2 ESE DC and AC System

What is the rms value of 20A peak current of an electrical device?

• 34.64 A.
• 17.32 A.
• 14.14 A.
• 12.74 A.

In an electrical drawing, the following items can be found EXCEPT

• total cost.
• title block.
• legend.
• suffix.

Resonance happens when Capacitor and Inductor are ………

• connected in parallel and have equal reactances
• connected in series and have equal reactances.
• connected in series and have equal resistances.
• connected in parallel and have equal resistances.

A 5.0 H choke coil with negligible resistance is connected to a 240V, 50Hz supply. What will be the value of the inductive reactance of the coil?

• 17.6 mW.
• 6.37 mW.
• 0.76 mW
• 0.64 mW.

The ratio between KW and KVA in an AC circuit represents the circuit

• Efficiency
• Power Factor.
• Phase Angle.
• Power Triangle.

When a pure resistor is connected across an AC supply, the phase shift between Voltage,V and Current,I is …….

• 180 degree.
• 90 degree.
• 45 degree.
• 0 degree.

The power factor improvement method recommended for a larger system which having too many low rating motors is

• unit.
• centralized.
• small.
• major.

A load is supplied with 60V,50 Hz AC supply. An ammeter series with the load shows 0.5 A. A Wattmeter connected to the system show 15W. What is the power factor?

• 0.25
• 0.5
• 0.75
• 1

For power factor correction panel, the ON-OFF switching of the capacitor bank is done automatically by using.

• In-rush reactor.
• power factor regulator.
• circuit breaker
• magnetic contactor

Determine the Power Factor of 20 KW, 3 phase, D-connected load if it draws a line current of 30 A when connected across 415 V, 50 Hz supply

• 0.93
• 0.66
• 0.54
• 0.31