EWRB THEORY CERTIFICATION TEST
WITH ACCURATE ANSWERS
◉ State TWO methods of reducing the stroboscopic effect of a
fluorescent fittings installed across three-phases. Answer: ANY
TWO:
- Connect fittings on different phases.
- In double-tube fittings, connect a capacitor in series with one
ballast or install lead/lag fittings.
- Intersperse incandescent lighting with the fluorescent lighting.
◉ Explain the term SENSITIVITY as it applies to a RCD. Answer:
Sensitivity is the current imbalance (earth leakage) required to trip
the RCD.
◉ In a Star connected electrical system, state the angle between line
voltage and phase voltage. Answer: 30º
◉ In New Zealand, what type of RCD is required to be voltage
dependent? Answer: Portable Residual Current Device (PRCD)
◉ State the maximum residual current rating for a RCD installed in a
patient treatment are. Answer: 10mA
, ◉ State TWO reasons why a RUN CAPACITOR would be fitted to a
single-phase, split-phase induction motor. Answer: ANY TWO:
- Quieter running.
- Better running torque.
- Less current draw.
- Increased efficiency.
◉ Name TWO components that are typically used to smooth the DC
output of a rectifier. Answer: ANY TWO:
- Capacitors
- Inductors
- Resistors
- Transistor
- Zener Diode
- Voltage Regulator
◉ Explain what is meant by the term, INVERSE TIME-CURRENT
CHARACTERISTIC in relation to a protective device. Answer: As the
current through the protective device increases, the time taken to
operate decreases.
WITH ACCURATE ANSWERS
◉ State TWO methods of reducing the stroboscopic effect of a
fluorescent fittings installed across three-phases. Answer: ANY
TWO:
- Connect fittings on different phases.
- In double-tube fittings, connect a capacitor in series with one
ballast or install lead/lag fittings.
- Intersperse incandescent lighting with the fluorescent lighting.
◉ Explain the term SENSITIVITY as it applies to a RCD. Answer:
Sensitivity is the current imbalance (earth leakage) required to trip
the RCD.
◉ In a Star connected electrical system, state the angle between line
voltage and phase voltage. Answer: 30º
◉ In New Zealand, what type of RCD is required to be voltage
dependent? Answer: Portable Residual Current Device (PRCD)
◉ State the maximum residual current rating for a RCD installed in a
patient treatment are. Answer: 10mA
, ◉ State TWO reasons why a RUN CAPACITOR would be fitted to a
single-phase, split-phase induction motor. Answer: ANY TWO:
- Quieter running.
- Better running torque.
- Less current draw.
- Increased efficiency.
◉ Name TWO components that are typically used to smooth the DC
output of a rectifier. Answer: ANY TWO:
- Capacitors
- Inductors
- Resistors
- Transistor
- Zener Diode
- Voltage Regulator
◉ Explain what is meant by the term, INVERSE TIME-CURRENT
CHARACTERISTIC in relation to a protective device. Answer: As the
current through the protective device increases, the time taken to
operate decreases.
