Maintenance of Electrical Equipment: A Complete Guide for Prospective Ground Engineers Studying for an “X” Licence

IN the previous section chemical methods of producing or storing electrical energy were considered. There is also the possibility of deriving the required electrical energy from some machine which converts mechanical energy into the electrical form. The ground engineer must appreciate that in no case can we get something for nothing, and that the output from the dynamo, plus the losses, does actually come from the engine of the aeroplane. Where the dynamo is wind‐driven, this is still true, the observable connexion being the reduction in the speed of the aeroplane when the dynamo is fitted. In fact, the speed of the aeroplane will vary with the electrical load on the dynamo, other conditions remaining constant, but this variation is too small or too obscured by other factors to be noticeable. In this section, the principles and general properties of the D.C. dynamo will be described.