Consider the following electric machine types: direct current, induction, synchronous and reluctance. State which machine you would propose to use in the following scenarios and motivate your answer. (a) In an explosive environment. (2) (b) The machine is connected to a load that needs to be maintained at a constant rotational speed. nothing there is nothing (2) (c) A machine whose speed can be controlled by controlling the applied voltage. (2) (d) The rotor of this machine is the simplest of those mentioned. (2) (e) A permanent magnet can be used to improve this machine’s efficiency
(a) Reluctance motors are safe for operation in explosion prone applications as they don't have a mechanical commutator.
2(b) The machine machine connected to a load which needs to operate at constant speed- Synchronous motors- As a synchronous machine always operates at a constant synchronous speed given by 120f/P
2(c) A machine whose spee can be controlled by controlling input voltage - DC machine - As in DC motor, the speed is directly proportional to the back EMF which in turn depends on the input voltage.
2(d) Simplest rotor design- Induction motor has the simplest rotor design . Squirrel cage induction motor simply contain short circuited bars to form it's rotor. It's the simplest and most robust rotor design as it has no windings. Needs very less maintenance.
2(e) using permanent magnets, rotor windings and mechanical commutation can be eliminated simplifying manufacture, reducing costs and improving reliability. At the same time efficiency is improved by the elimination of the need for excitation of the rotor windings and by avoiding the frictional losses associated with the commutator.
Brushless versions of both DC and AC motors are available.
For DC- BLCD motor
For AC- Reluctance motors having permanent magnet
Consider the following electric machine types: direct current, induction, synchronous and reluctance. State which machine you...
(might be 1 or 2, MCQ questions were having images given with them, which we couldn't insert, so ignore those questions if you cannot answer, sorry for inconveinience created, i tried to delete them but might be couldn't done all) 3) Single phase induction motors work because: a) The oscillating magnetic field can induce starting torque in a rotor. b) The oscillating magnetic field can induce running torque in a rotor. c) A capacitance or inductance can create the phase...