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WorksheetsFORMATIVE ASSESSMENT 3: AC GENERATOR
Total questions: 10
Worksheet time: 7mins
Which diagram represents the voltage output of a simple a.c. generator?
The frequency of generated emf in an alternator is given by:
N = 120f /P
N = fP / 120
N = 60f /P
N = f/P
Which type of rotor is used in high-speed alternators?
Salient pole
Cylindrical rotor
Induction type
Reluctance rotor
The generated emf equation of an alternator is:
E = PΦZN / 60A
E = V - IaRa
E = 2πfNΦ
E = 2.22 kp kd fΦZ
A salient pole rotor is generally used in:
High-speed alternators
Low-speed alternators
Both high and low speed
Small DC machines
An alternator three phase, have two poles, 210 conductors inside the armature winding and value of flux per poles is 17.5mWb. The waveform for this machine is a sinusoidal and the frequency to generate the voltage is 50Hz. Assume that kd and kp is unity. Calculate the rms voltage generates in a single phase.
135.98V
128.98V
120.22V
108.22V
In a star connection, the line voltage is:
Equal to phase voltage
√3 × phase voltage
3 × phase voltage
½ × phase voltage
In a delta connection, the line current is:
½ × phase current
√3 × phase current
3 × phase current
Equal to phase current
