3.17. A 200-turn coil is rotating at a speed of 3600 rpm in a 4-pole generator. The flux per pole is 2 mWb. Determine (a) the frequency of the induced emf, (b) the maximum value of the induced emf, (c) the rms value of the induced emf in an ac generator, and (d) the average value of the induced emf in a dc generator.

4. Draw a circuit model of a separately excited DC Generator.

An 6-pole d.c generator has 300 armature conductors, and a useful flux of 14 mWb per pole. What will be the em.f. generated if it is lap-connected and runs at 1420 rpm? What must be the speed at which it is to be driven produce the same e.m.f. if it is wave-wound?

D2. When a generator's full-load output voltage is the same as its no-load output voltage it is said to be a) under-compounded b) flat-compounded c) over-compounded d) none of the above D3. The output of an overcompounded DC generator can be lowered by use of a a) rheostat connected in series with the series field b) rheostat connected in parallel with the series field c) rheostat connected in parallel with the shunt field d) none of the above D4. When might it be desirable to use an overcompounded generator? a) never b) always c) to compensate for line loss d) when you need a higher no-load voltage than your full-load voltage