Module 7745 Chapter E

How many Radians are there in a circle

• $2\pi$

• $4\pi$

• $\pi$

• $\frac{\pi}{2}$

For a sine wave, what is the relationship between the rms value and the peak value?

• The rms value is 0.707 x peak value

• The peak value is 0.707 x rms value

• The rms is twice the value of peak value

• The rms is half the value of peak value

In the equation

 $True\ power\ =V\times I\times\cos\theta$  

what does  $\cos\theta$  represent?

• The Power Factor

• Apparent power

• The reactive component of the circuit

• The resistive component of the circuit

What does a polyphase system refer to?

• Any system with more than one phase

• Any symmetrical phased system

• Any balanced phased system

• Any 3 phased system

If all voltage outputs of a 3 phase 115Vac Generator were vector summed to together, what would be the Total Voltage?

• 0 Vac

• 200 Vac

• 115 Vac

• 345 Vac

Select all correct statements for a symmetrical 3 phase system.

Select 1 or more answers

• The supply Voltage to each phase have the same frequency

• The supply current to each phase have the same magnitude

• There is equal phase displacement

• The current in the line conductors are equal

What is the relationship between the current magnitudes in a 3 phase Delta connected system?

• $I_L=\sqrt{3}I_P$

• $I_L=I_P$

• $I_P=\sqrt{3}I_L$

• $I_P=I_LCos\theta$

What is the relationship between the current magnitudes in a 3 phase Star connected system?

• $I_L=\sqrt{3}I_P$

• $I_L=I_P$

• $I_P=\sqrt{3}I_L$

• $I_P=I_LCos\theta$

Which of the following formula will give you the total power for a 3 phase star connected system?

• $3\times V_P\times I_P\times Cos\theta$

• $\sqrt{3}\times V_P\times I_P\times Cos\theta$

• $\sqrt{3}\times V_P\times I_L\times Sin\theta$

• $3\times V_L\times I_L\times Sin\theta$