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**AC Fundamentals Questions**

**What is the definition of a generator?**

A generator is a machine which converts mechanical energy to electrical energy.**What is the definition of an alternator?**

An AC generator is also called an alternator.**With a six pole alternator spinning at 1200 rpm, what would the frequency of the voltage be?**

\[f=\frac{n*p}{120}=\frac{1200*6}{120}=60Hz\]

**To generate an output frequency of 6oHz, what would be the rpm speed need to be with an eight pole alternator?**

\[n=\frac{120*f}{p}=\frac{120*60}{8}=900RPM\]

**In North America what is the standard frequency of AC voltage generated?**

The standard frequency in North America is 60 Hz**With a voltage of 240-V RMS, what would be the peak voltage?**

${{V}_{p}}=\sqrt{2}{{V}_{rms}}=1.414*240=339V$

**Using an AC volt meter we found the AC sine wave voltage to be 10-Volts.****Determine the peak value of this voltage.**

${{V}_{p}}=\sqrt{2}{{V}_{rms}}=1.414*10=14.14V$**Determine the RMS value of this voltage.**

Measured voltage is RMS voltage; 10-V rms.**Determine the peak to peak value of this voltage.**

Peak x 2 = peak to peak; 14.14 x 2 = 28.28 volts peak to peak.

**List the two single phase voltages in a residential system.**

120-V and 240-V AC**The direction of rotation of an induction motor is affected in what way by interchanging the supply phases?**

By interchanging the supply phases the motor will run in reverse.**When connecting a three phase alternator to the power system, what conditions must be met?**

**1.**The phase sequence or rotation of the machine must be the same as that of the system.

**2.**The alternator voltage must be in phase with the grid system.

**3.**The alternator frequency must be the same as the grid system frequency.

**The three stator coils of a three phase alternator are positioned apart by how many electrical degrees?**

The stator coils must be set to 120 degrees apart.**There are two basic types of three phase alternator coil connections, what are they?**

The Wye and Delta connections.**In an AC resistive circuit, what is the phase relationship between the voltage and current?**

The current and voltage are in phase.**A 10 ohm heater is connected to an AC 340-V peak-to-peak voltage determine:****The peak value of the voltage.**

340-V/2 = 170-V peak**The effective value of the voltage.**

$\frac{170}{\sqrt{2}}=120V$**The wattage.**

120V/10Ω = 12Amps;

12A x 120V = 1440 Watts

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