PHEP_26B

Question 1

Thermal instruments are used to measure: a) DC b) AC c) heat d) none of the above

Answer 1

c) heat ref: p. 10

Question 2

Most meter mechanisms are designed to take advantage of two of the effects of current in an electric circuit: a) magnetism-voltage b) heat-magnetism c) heat-voltage d) resistance-heat

Answer 2

b) heat-magnetism ref: p. 45

Question 3

The type of meter or instrument using the heat-producing effect of current is called a: a) watt instrument b) thermal instrument c) current potential d) voltage instrument

Answer 3

b) thermal instrument ref: p. 45

Question 4

A wattmeter measures: a) power factor b) current potential c) current-resistance d) current-voltage

Answer 4

d) current-voltage ref: p. 20

Question 5

Most watt meters are a/an: a) D’Arsonval meter b) electrodynamometer c) potential-coil meter d) iron-vane meter

Answer 5

b) Electro-dynamometer ref: p. 20

Question 6

The D’Arsonal electromagnetic movement: a) is suitable for either DC or AC measurements b) is used only for AC measurements c) can be converted to read AC by using a bridge rectifier unit in the coil circuit d) is not affected by the magnetic effects of AC

Answer 6

c) can be converted to read AC by using a bridge rectifier unit in the coil circuit ref: p. 5

Question 7

A copper-oxide rectifier is a device that: a) converts DC to AC b) offers high opposition to current in two directions c) is classed as a uni-directional conductor d) has two good conductors of electricity

Answer 7

c) is classified as a uni-directional conductor ref: p. 5

Question 8

AC voltages in the higher ranges are usually measured with a: a) voltmeter and potential transformer b) voltmeter and current transformer c) multiplier and voltmeter d) millivolt meter and a shunt in parallel

Answer 8

a) voltmeter and potential transformer ref: p. 16

Question 9

The range of an AC ammeter may be extended by using a: a) condenser b) straight shunt c) current transformer d) all three of the above

Answer 9

c) current transformer ref: p. 14

Question 10

AC ammeters are generally calibrated to read root-mean-square valves. This also means the ammeter is calibrated to read: a) peak values b) effective values c) average values d) none of these

Answer 10

‘b) effective values ref: p. 5

Question 11

In the absence of a power-factor meter the power factor of a certain electrical load may be determined by using: a) a wattmeter b) a voltmeter and an ammeter c) a watt-hour meter d) a wattmeter, a voltmeter and an ammeter

Answer 11

d) a wattmeter, a voltmeter and an ammeter ref: p. 22

Question 12

The junction of the two dissimilar metals of a thermocouple produces a flow of current when the junction is: a) surrounded by a DC magnetic field b) heated c) wet d) all of the above

Answer 12

b) heated ref: p. 13

Question 13

Which one of the below instrument types would not utilize the effect of current to measure voltage? a) electrostatic b) D’Arsonval c) electromagnetic d) electrodynamometer

Answer 13

a) electrostatic ref: p. 1

Question 14

The meter measuring mechanism used in recording instruments is basically the same as that used for the conventional indicating instrument except in the area of: a) coil arrangement b) fixed visual scales c) circuit arrangement d) instrument damping setting

Answer 14

d) instrument damping setting ref: p. 16

Question 15

The circuit measuring arrangement of most ground detector meters shows the neutral points of the ground detector potential transformer primary winding to be: a) fused b) solidly grounded c) connected to its associated meter d) ungrounded

Answer 15

b) solidly grounded ref: p. 20

Question 16

The meter whose indicated reading would be equal to E x I x sin(theta) is a: a) varmeter b) wattmeter c) watt-hour meter d) power-factor meter

Answer 16

a) varmeter ref: p. 21

Question 17

The reliability or accuracy of power-factor meter readings would be affected the least when used on: a) single-phase circuits b) two-phase circuits c) three-phase circuits d) the accuracy is not affected by an unbalanced load

Answer 17

a) single-phase circuits ref: p. 24

Question 18

The restoring torque in the concentric- scale type of frequency meter is provided for by the: a) two oppositely wound spiral springs b) the action of a modified wattmeter movement c) the action of the repulsion type movement d) installing an external impeder in the central circuit

Answer 18

c) the action of the repulsion type movement ref: p. 27

Question 19

The speed at which the pointer is rotating on a synchroscope is affected by: a) the frequency difference between the incoming and running generator b) whether the incoming generator is running slower or faster that the running generator c) the phase difference between the two voltages d) all three of the above

Answer 19

a) the frequency difference between the incoming and running generator ref: p. 37

Question 20

Each element of a polyphase watt-hour meter contains: a) only an induction type motor b) only a registering device and an induction type motor c) only a retarding device and an induction type motor d) an induction type motor, a registering device, and a retarding device

Answer 20

‘d) an induction type motor, a registering device, and a retarding device ref: p. 40