4.1 Which of the following statements about a squirrel cage induction motor is false? (a) It has no external electrical connections to its rotor. (b) A three phase supply is connected to its stator. (c) A magnetic flux which alternates is produced. (d) It is cheap, robust and requires little or skilled maintenance. 4.2 Which of the following statements is false when referring to a three phase induction motor? (a) The synchronous speed is half the supply frequency when it has four poles. (b) In a 2 pole machine, the synchronous speed is equal to the supply frequency. (c) If the number of poles is increased, the synchronous speed is reduced. (d) The synchronous speed is inversely proportional to the number of pole.

I have an assignment of topic: construction of DC Machine I need to write theory discussion with some figures

Figure Q4.c shows an alternative regulator circuit that could be used in a DC powersupply design to regulate the output of a rectifier. Determine the suitability of the regulator for a rectifier with the output specifications asgiven in Table 4. The ripple voltage of the rectifier is 30% of Vpk, and the regulatorneeds to deliver to the load the current of Io mA.The Zener diode power rating is 2W. The required output voltage is 7.4V. For the circuit in Figure Q4.c: determine the required Zener diode voltage Vz; find a suitable value of the resistor R; determine the minimum requirement for the transistor power rating PTR. 2) What is the role of the resistor R in this circuit? Show your working throughout and state any assumptions you may make.Provide commentary to your design process, and evaluate your design.

The 3-phase half-wave diode rectifier feeds a load consisting of a 50-ohm resistor. The sinusoidal sources in the input of the rectifier are wye-connected and phase-to-phase rms voltage is 380 volts. Calculate the power (in watts) absorbed by the load. Assume the diode is ideal. a. 680.36 b. 2267.90 C. 4082.20 d. 1700.90 e. 1360.70