Question

A certain circuit consists of three resistors connected in parallel across 200V mains. The rate of production of heat in them is in the ratio of 5:3:2 and together they generate heat at the rate of 1 kWh in 2 h. Find the power used if the three resistances are connected in series across 248V mains.

A 3-phase six pole, 60 hz, 230-V wound rotor motor has its stator connected in delta and its rotor connected in wye. The stator to rotor turn ratio is 75 percent. What is the rotor induced emf per phase if normal voltage is applied to the stator when the rotor slip is 4%?

7 V

12 V

9 V

5 V

The full load slip of a 3 induction motor is 6%. If the motor has secondary resistance of 0.08 ohm per phase. What is the rotor power developed of the rotor current is 40 amperes?

6 hp

2.7 hp

8 hp

10 hp

A 3 phase 4 pole induction motor delivers power to a mechanical load of 100 kw. Friction and windage loss is 5 kw. If the motor is running with 4% slip, what is the air gap power?

105 kw

95 kw

109.4 kw

100 kw