Chapter 26-27 AC Circuits

Pulsates/never fails to zero

In three-phase power systems, the delivered power ________________.

Series

One of the most commontypes of low-pass filters is an inductor connected in ____ with a load resistor.

Resemble the greek letter (Pi)

Pi-type filters are so named because they ________________________________.

Schematically resembles a T

T filters are so named because they ________________________________..

Resistance

The _____ of a tank circut varies with frequency.

Line Current

The alternator must supply the ______ ______ for each of the loads.

Q

The bandwidth of a filter depends on the ___ of the components.

Low-Pass

When a filter offers little opposition to a frequency it is said to be _____ _____.

1

When calculating the power of a pure resistive load, the voltage and current are in phase with each other and the power factor is _____.

Trim

A ____ capacitor is used to adjust circuit resonance.

Filter

A ____ is used to select one particular station from the thousands available.

Wye-connected

Line current and ohase currents are the same in the _____________ configuration.

Parallel

In a ____ circuit, the impedance of the tank circuit is relatively low until the resonant requency is reached.

75%

In a balanced three-phase system., the co ductors need be only about ____ the size of conductors for a single-phase, two-wire system of the same kilovolt-ampere (kVA) rating.

Wye/Star

The three-phase connection in which one end of each of the windings are connected together is called the _____________________ connection.

Delta

The three-phase connection in which three seperate inductive loads have been connected together is the ___________ connection.

3

In calculating power in a three-phase circuit, the phase values of voltage and current are multiplied by_____.

1.732

Often in calculations of values in three-phase systems, the square root of three occurs. The approximate value of this constant is ________.

High Pass

When a filter circuit offers much opposition to a frque cy it is said to be ___ ____.

480V

A delta connected set of windings has a phase voltage of 480 V. What is the value if the line voltage?

17.32 A

A delta-connected set of windings has a phase current of 10 A. The line currents is __________.

13.33A

A delta-connected three-phase alternator is driving a wye-connected resistive load. The alternator output voltage is 480 V. The load resistors are 12 ohms each. What is the phase current in the alternator?

Offers high opposition to current flow

A high-pass filter is one that______________________________________________.

6.935A

A wye-connected alternator that has phase voltages of 277 V is feeding two loads. The first load is wye-connected inductors that have 40 ohms of XL. The second load is delta-connected capacitors that have Xc of 60 ohms. How much is the alternator phase current?

Star

Another name for the three-phase wye connection is the ___ connection.

High-Pass

Filters that are designed to reject low frquencies are _____ ____ filters.

120 Degrees

Three-phase boltages are _____ out of phase with each orher.

Multiplying the Apparent Power (VA) by the power factor (PF%)

In a three-phase circuit, the true power (watts) is found by _________________________________.

Phase

In a three-phase connection, the voltage measured across a sjngle winding is the _____.

Line

In a three-phase connection, the voltage measured between the lines is the ______ voltage.

Resonance

A high-pass filter produces a sharp curve and the output sinal peaks at the point of _____.

Offers low impedance on both sides but not middle

A band-rejection filter is one that ____________________________.

Rejects all except in the middle

A bandpass filter is one that ______________________________________.

Little opposition to current flow

A low-pass filter is one that _________________________________________.

Band Rejection

A notch filter is another name for a ______ _______ filter.

Wider

Variable capacitors generally provide a ____ range of thning than variable inductors.

100V

A delta connected set of windings has a phase voltage of 100v. The line voltage is _______ .

Bandpass

Filters that pass a range of frequencies while tejecting frequencies on either side are called ______ filters.

VARSc

If a three-phase load is a pure reactive load, then the piwer calculated has units of __________.

150%

The horsepower rating of three-phase motors and the kilovolt-ampere rating of three-phasetransformers are about ______ greater than for single-phase motors or transformers with a similar frame size.

Low-Pass

____ ___ filters offer little opposition to current flow when the frequency is low.

Band Rejection

______ ______ filters are designed to exhibit low impedance to frequencies on either side if their resonant frequency.