what is the biggest disadvantage of the permanent-magnet moving-coil instrument

1. The biggest disadvantage of the permanent-magnet moving-coil instrument is that it

 

(a) has very low power consumption

(b) will not read alternating values

(c) has a linear scale

(d) has built-in damping

2. The biggest disadvantage of the rectifier permanent-magnet moving-coil instrument is that it

(a) cannot read direct-current values

(b) can be adapted as a multi-range instrument

(c) is extremely large and heavy

(d) is in error if the applied wave-shape is not sinusoidal

3.The biggest advantage of the moving-iron instrument is that is

(a) reads true RMS values (b) is inaccurate

(c) needs special damping (d) has a non-linear scale

4 The most usual application of the dynamometer instrument is as

(a) an ammeter (b) a voltmeter

(c) a wattmeter (d) a frequency meter

5 An additional resistor is often connected in series with an instrument across a shunt to compensate for changes in the resistance of the instrument as temperature changes. The resistor is known as a

(a) PTC resistor (b) series resistor

(c) swamping resistor (d) NTC resistor

6 A voltmeter movement gives full-scale deflection when carrying a current of

25 μA. Its sensitivity will be

(a) 40 k_/V (b) 25 k_/V (c) 40 _/V (d) 40 kV/_

find the cost of your paper

Sketch the load characteristics, terminal voltage/load current, of the following types of DC generator

1. (a) Sketch the load characteristics, terminal voltage/load current, of the following types of DC generator: (i) series-connected, (ii) shunt-connected and (iii) compound-connected.   (b) State one purpose for which….

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1. Sparking at the trailing edges of the brushes in a DC machine is usually prevented by fitting   (a) copper gauze brushes (b) a compensating winding (c) a compound….

Calculate the synchronous speed of a 10-pole three-phase machine connected to a 50 Hz supply.

1. The generator characteristic shown in Figure 9.28 is for a   (a) shunt machine (b) series machine (c) differentially compounded machine (d) cumulatively compounded machine 2.The speed of a….