Computer-aided Design of Electrical Machines

CHAPTER 1
Concept of Computer-Aided Design and
Optimization
1.1 Introduction
A design problem has to be fonnulated considering the various constraints, processes,
availability of materials, quality aspects. cost aspects etc. Constraints can be from
technical, cost or availability aspects. Technical constraints can be from calculation
methods, available process systems, skilled labour, manufacturing facilities, machinery,
or tools etc. Sometimes transport facilities to site also pose problems. If suitable quality
. materials are not available indigenously they may have to be imported, which effects
cost and delivery time.
In designing -any system, accuracy of prediction, economy, quality and delivery
period playa vital role. Basically, a design involves calculating the dimensions of
various components and parts of the machine, weights, material specifications, output
parameters and perfonnance in accordance with specified international standards. The
calculated parameters may not tally with the final tested perfonnance. Hence, design has
to be frozen keeping in view the design analysis as well as the previous operating
experience of search machines.
The practical method in case of bigger machines is to establish a computer program
for the total design incorporating the constraint parameters and running the program for
various alternatives from which final design is selected.
Though the final design may meet all the required specifications, it need not be an
optimal one as regards the weight and cost of the active materials, and certain
perfonnance aspects like efficiency, temperature rise etc.
Various Objective Parameters/or Optimization in an Electrical Machine
(a) Higher Efficiency
(b) Lower weight for given KVA output (Kg/KVA)
© Lower Temperature-Rise
(d) Lower Cost
(e) Any other parameter like higher PF for induction motor, higher reactance etc.
Here we have to understand that if an optimized design is finalized keeping in view
of any of the parameters mentioned above, the design may not be optimum for the above
parameters. For example, if a design is selected for higher efficiency, it may not be
optimum in other parameters, maybe the cost is high. Nonnally this is a case where…