Industrial Power Supplies, Inverters and Converters: Quiz

QUESTIONS

1. Explain the operation of a single-diode half-wave rectifier and draw its input and output waveforms.
2. Explain the operation of a two-diode center-tapped rectifier that produces a full-wave output and draw its input and output waveforms.
3. Explain the operation of a four-diode full-wave bridge rectifier and draw its input and output waveforms.
4. Explain the function of the capacitor and inductor in a power supply.
5. Explain the function of a zener diode in a power supply.
6. The fuse in a circuit can only protect against an overcurrent. Explain what components can be added to the circuit to protect it against overvoltage conditions.
7. Explain the operation of an uninterruptible power supply.
8. Explain the operation of an inverter.
9. List three types of inverter circuits and explain the output waveform of each.
10. Explain the difference between a linear power supply and a switch-mode power supply.

TRUE OR FALSE

1. The output of a single-phase half-wave rectifier is two positive pulses for each sine wave input.
2. The rms value of voltage will always be smaller than the peak value for the same voltage.
3. The three-phase full-wave rectifier uses six diodes and has six half-wave outputs.
4. An inverter changes DC voltage to AC voltage.
5. A converter changes DC voltage to AC voltage.

MULTIPLE CHOICE

1. Power goes through an uninterruptible power supply and travel throughout the components to the load in the following order:_________
   1. surge protection section, rectifier section, battery, and then to inverter section.
   2. surge protection section, inverter section, battery, and then to rectifier section.
   3. surge protection section, battery, rectifier section, and then to inverter section.
2. The crowbar circuit uses______.
   1. an over-voltage-sensing circuit and triac to cause the circuit fuse to open when an over-current condition is sensed.
   2. an over-voltage-sensing circuit and an MOV to cause the circuit fuse to open when an over-voltage condition is sensed.
   3. an over-voltage-sensing circuit and an SCR to cause the circuit fuse to open when an over-voltage condition is sensed.
3. A pulse-width modulation (PWM) inverter provides
   1. an output waveform that can have its voltage, current, and frequency varied.
   2. an output waveform that can have only its voltage varied.
   3. an output waveform that can have only its current and frequency varied.
4. A chopper is____.
   1. a converter circuit that changes ac to dc.
   2. an inverter circuit that changes dc to dc.
   3. a converter circuit that changes dc to dc.
5. A switch-mode power supply (SMPS) consists of the following circuits:
   1. an input inverter circuit, a high-frequency switch, a power transformer, and an output inverter circuit.
   2. an input rectification circuit, a high-frequency switch, a power transformer, and an output rectification circuit.
   3. an input rectifier circuit, an input voltage regulator, a high-frequency switch, an output voltage regulator, and an output rectification circuit.

PROBLEMS

1. Calculate the average dc output voltage from the input rms voltage for the single-diode half-wave rectifier if the voltage at the transformer secondary is 208 volts rms.
2. Calculate the average dc output voltage for a two-diode center-tapped rectifier if the input voltage at the secondary of the transformer is 230 volts rms.
3. Calculate the average dc output voltage for a four-diode full-wave bridge rectifier if the input voltage at the secondary of the transformer is 230 volts rms.
4. Show two ways that MOVs can be connected in a power supply to protect it from overvoltage.
5. Draw the circuit for a linear power supply, explain the points you would test, and describe the waveform of the voltage at each point.
6. Draw two ways SCRs can be used in crowbar circuits and explain the operation of each of the circuits.
7. Draw the block diagram circuit for an uninterruptible power supply and identify its components.