The level of prosperity of a community is related to its capability to produce
goods and services. But producing goods and services is strongly related to the
use of energy in an intelligent way.
Motion and temperature (heat) control are paramount in energy usage.
Energy comes into use in a few forms such as thermal, mechanical and
electrical.
The level of prosperity of a community is related to its capability to produce & v: s- q% |2 G. Agoods and services. But producing goods and services is strongly related to the" W2 W6 g0 a0 A0 w
use of energy in an intelligent way. . D* d8 \9 W; s& v: d |0 T/ CMotion and temperature (heat) control are paramount in energy usage.* u! V3 l( l0 V6 q0 ]0 s: ~0 R5 `# ^
Energy comes into use in a few forms such as thermal, mechanical and ! ~4 r/ Y% I' |3 |/ Y7 delectrical.4 q+ {5 h* C6 C' i$ {( l
Electrical energy, measured in kWh, represents more than 30% of all used 0 f( _3 S$ U- M" G) t; ]+ Yenergy and it is on the rise. Part of electrical energy is used directly to produce( w" o7 y, W, }2 J& k4 |; D2 c
heat or light (in electrolysis, metallurgical arch furnaces, industrial space" L0 q m! R& m$ W4 v0 L
heating, lighting, etc.)., g& c- `/ I W
The larger part of electrical energy is converted into mechanical energy in 0 G W8 k! J# K2 |2 F' y& zelectric motors. Among electric motors, induction motors are most used both for8 |# P+ e$ u) S
home appliances and in various industries [1-11]." \/ [2 M0 `( l# `
This is so because they have been traditionally fed directly from the threephase ) T0 p/ R. ]- i5 S. q3 K. ya.c. electric power grid through electromagnetic power switches with ( j1 J, N3 o: L Zadequate protection. It is so convenient. % \ k" v: b* M/ s- DSmall power induction motors, in most home appliances, are fed from the ; I6 Q4 b& n! hlocal single phase a.c. power grids. Induction motors are rugged and have : A% X8 W5 |% W3 E% fmoderate costs, explaining their popularity.& `% ? y" _5 V4 B+ t
In developed countries today there are more than 3 kW of electric motors& u) t. p7 |. T4 h
per person, today and most of it is from induction motors. " N$ b$ R# T) C9 F& GWhile most induction motors are still fed from three-phase or single-phase # m3 m" U- l2 k5 ?4 upower grids, some are supplied through frequency changers (or power $ \ Y4 q5 L" C8 I8 X$ gelectronics converters) to provide variable speed.8 o' l; H3 c& N$ e
In developed countries, 10% of all induction motor power is converted in , k9 L, U1 N* n' mvariable speed drives applications. The annual growth rate of variable speed 9 f5 ?+ p, }) @7 x9 _% [4 K* \drives has been 9% in the last decade while the electric motor markets showed$ ]. i: a% N- r
an average annual growth rate of 4% in the same time.5 v9 r o' Y& r4 a$ E
Variable speed drives with induction motors are used in transportation,. V; q E1 r; W
pumps, compressors, ventilators, machine tools, robotics, hybrid or electric 8 \+ w& Z9 y3 {7 Zvehicles, washing machines, etc./ T9 t- c. {8 [# f5 G: y' b
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