Engineering Dudes

Repulsion type Moving Iron instruments and Dynamometer type wattmeter 1. Construction and working of  Repulsion Type Moving Iron Voltmeter/Instruments. Construction : One variation of moving iron instrument is repulsion type instrument. Here we keep the shaft of the moving system along the axis of the coil. We attach a soft iron bar or rod to the shaft so that it can move with the movement of the moving system. We fix another soft iron bar or rod with the inner coil body as shown. When there is no current in the coil, both iron bars are nearest to each other. Working : The current in the coil produces the magnetic field. The magnetic field induces same magnetic poles to similar ends in both of the iron bars or rods. Naturally, these two iron bars repel each other. The repulsive force causes the deflection of the pointer attached to the moving system. This is because due to the repulsive force, the bar attached to the moving system tries to go away from the bar fixed to the inner co...

  D.C. Generator Construction and working principle of DC Generator DC Machines are mainly divided in two types Motor and Generator. Here we see only about Generator. Motor will be covered in another blog. Working principle of DC generator : All the generators work on a principle of dynamically induced E.M.F.  This principle nothing but the Faraday’s law of electromagnetism induction.  It states that, “When electric supply given to any conductor it produces magnet fluxes around it these fluxes link with a conductor or a coil. Then voltage is produced in that conductor or coil.’ But this happened only when there exists a relative motion between a conductor and the flux.” The relative motion can be achieved by rotating conductor with respect to flux or by rotating flux with respect to a conductor. So, a voltage gets generated in a conductor, as long as there exists a relative motion between conductor and the flux. Such an induced EMF which is due to the physical movem...