Determination of Stray Losses using myDAQ

DC machine is one of the most important electrical machines. This particular test is applicable to shunt motors and generators and is used for finding stray losses. By knowing the armature and shunt Copper losses at a given load current, efficiency can be calculated. The machine under test is speeded up slightly beyond its normal speed and then supply is cut off from the armature while keeping the field excited. Consequently, the armature slows down and its kinetic energy is used to meet the rotational losses i.e. friction and windage losses.