DC Machines

Commutation in DC Machine or Generator or Motor: One coil each under an adjoining pole-pair is connected between adjacent commutator segments in a lap-wound dc armature, while in a wave-wound armature the only difference is that P/2 coils under the influence of P/2 pole-pairs are connected between adjacent segments. Coil(s) current is constant and unidirectional […]

Compensating Winding in DC Machine: Compensating Winding in DC Machine – It was seen from earlier section, that armature reaction causes the flux density wave to be so badly distorted that when a coil is passing through the region of peak flux densities, the emf induced in it far exceeds the average coil voltage. If

Armature Reaction in DC Machine: When the armature of a dc machine carries current, the distributed armature winding produces its own mmf (distributed) known as armature reaction in DC Machine. The machine air-gap is now acted upon by the resultant mmf distribution caused by simultaneous action of the field ampere-turns (ATf) and armature ampere-turns (ATa).

Circuit Model of DC Machine: The parallel paths of DC machine armature are symmetrical and each has an induced emf Ea and a resistance Rp. The armature can be represented by the Circuit Model of DC Machine with voltage Ea and a series resistance as shown in Fig. 7.5. The armature resistance is quite small so

EMF and Torque Equation of DC Machine: EMF and Torque Equation of DC Machine – It was shown in Sec. 5.2 (Fig. 5.14 (a)) that in a dc machine the magnetic structure is such that the flux density wave in the air-gap is flat-topped with quarter-wave symmetry so long as the armature is not carrying

Introduction of DC Motor: Introduction of DC Motor is constructed in many forms and for a variety of purposes, from the 3-mm stepper drawing a few μA at 1.5 V in a quartz crystal watch to the giant 75000-kW or more rolling mill motor. It is a highly versatile and flexible machine. It can satisfy