Following the successful development of a bistable electromagnetic switchge
ar actuator for driving vacuum interrupters in an autorecloser, several MV
switchgear companies have begun to develop similar actuators for use in aut
oreclosers powered by primary lithium batteries. However, many of these act
uators consume excessive energy in operation, adding undesirable battery co
st to the equipment. A model is developed that enables these actuators to b
e optimised in energy terms, since it simulates the electrical. magnetic an
d mechanical effects seen by the actuator and their interactions. The model
is a detailed lumped reluctance type. The lumped reluctances were defined
after inspecting the results of the finite element analysis of a generic ac
tuator. The model uses iteration routines to calculate the flux distributio
n within it and an improved stochastic optimal method to obtain an optimal
design, in terms of magnet cost and operating energy usage. Simulated and t
est results are presented, and these show a close correlation.