A compound generator has a lap-wound armature with 200 slots and four turns per coil. It is rotating with a speed of 80 rpm and flux per pole is 100mWb. The armature resistance is 12 and shunt field resistance is 2002. The series field resistance is 22. Determine: i) Terminal voltage (ii) If a load is connected to the terminals which starts pulling a load current such that the flux that is produced by the series field is added into the shunt field to keep the new induced voltage to be the same as the induced voltage at no load, what will be the new terminal voltage if the shunt field current is dropped to 90% of the shunt field current at no load? (iii) Power dissipated in the load Draw equivalent circuits

1. The operation of Commutator in DC Motor is * O a) to convert dc to ac O b) to convert ac to dc O c) to convert fixed dc to variable dc O reverse the current direction in the rotating windings each half turn

The voltage induced by a 6-pole DC generator running at 600 [RPM] with 100 slots on the armature and each armature coil has 4 turns with a flux per pole of 0.01 [Wb] is

An electromagnet has a movable iron part and dimensions of magnetic circuit with uniform cross section as shown in figure. The core is made of ferromagnetic material with relative permeability of 3000: a) b) c) Calculate the magnetic reluctance of the circuit and the inductance of the main winding. Determine the air-gap flux, the flux density and the field intensity of the core and gap. Because of a fault in the power supply, the exciting current is increased to 8 A causing the mobile element of the iron core to move to a zero gap position as a result of the excessive electromagnetic force action. If this movement occurs in 0.01 s, find the transient voltage induced in the test coil having two turns. 0.5 mm air-gap 2 cm 2 A 3 cm 2 cm 60 turns 18 cm test coil 24 cm 0.5 mm air-gap