October 2021

[sc_fs_faq html=”true” headline=”h2″ img=”” question=”Mention speed control methods of DC shunt motors?” img_alt=”” css_class=””] 1. Armature control method, 2. Field control method, 3. Voltage control method [/sc_fs_faq] The speed of a dc motor is given by [latex]N=\frac{V-I_{a} R_{a}}{Z \phi}\left(\frac{A}{P}\right) \text { (or) } \quad N=\frac{K\left(V-I_{a} R_{a}\right)}{\phi} [/latex] where  V = applied voltage, Ia = armature current Ra

There are three types of characteristics. Open circuit characteristics (OCC) or magnetisation characteristics (E2 versus If). Internal characteristics or total characteristics (E versus Ia). External characteristics or voltage regulated characteristics (V versus IL) Separately excited DC generator characteristics For a given dc generator it is clear that the induced emf is proportional to the flux

DC generators can be classified according to their methods of field excitation. There are two types of DC generators on the basis of excitation. Separately excited DC generators Self excited DC generators Separately excited DC generators If the field winding is excited by a separate DC supply, then the generator is called separately DC generator.

DC Generator : An electrical generator is a rotating machine which converts mechanical energy into electrical energy. It is shown in figure. This energy conversion is based on the principle of electromagnetic induction. According to Faraday’s laws of electromagnetic induction, whenever a conductor is moved in a magnetic field, dynamically induced e.m.f is produced in