losses in dc shunt machine
TRANSCRIPT
COMPUTE AND SEPARATE THE LOSSES IN
DC SHUNT MACHINE
By N.Tejaswani
LOSSES MEANS…………
• The basic function of a dynamo is the conversion of energy, either from mechanical to electrical form or from electrical to mechanical form. Whole of the input to the dynamo is not converted into useful output energy but a part of the input energy is converted into heat and is lost for the useful output purpose of the machine. The energy converted into heat is called the ENERGY LOSS.
TYPES OF LOSSES……….
• Copper Losses or Electrical Losses• Core Losses or Iron Losses• Brush Losses• Mechanical Losses• Stray-Load Losses
COPPER OR ELECTRICAL LOSSES…
These losses are the winding losses because these occurs in the winding of the machine.
Armature current losses= = Ia2Ra
Copper losses in shunt field of a machine=Ish2Rsh
Copper losses in interpole winding=Ia2Ri
Copper losses in a series field machine=Ise2Rse
Copper losses in a compensating windings=Ia
2Rc
CORE LOSSES OR IRON LOSSES…
These losses are also called as magnetic losses. These losses are constant about 20% of a full load losses
Core losses are of two types1. Hysteresis losses2. Eddy current losses
BRUSH LOSSES…
Power loss at the brush contacts between the copper commutator and the carbon brushes.
MECHANICAL LOSSES..
The losses associated with mechanical effects are called as MECHANICAL LOSSES. They consists of bearing friction loss and windage loss.
These losses are usually very small.
STRAY LOSSES…
Stray losses are results from1. The distortion of flux because of Armature
reaction2. Short circuit currents in the coil, undergoing
commutation etcStray losses are assumed as 1% of full load
output power
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