of the electricity consumed by industry is used by electric motors. Older
motors being the most wasteful. If all electric motors in use were as
good as the best designs currently available the saving in terms of CO2
emitted into the atmosphere would be reduced dramatically. Furthermore,
if these motors employed controls to govern speed, switching and energy
efficiency, that saving would be increased by a further order of magnitude.
Estimates suggest less than 5% of the AC motors in use in Britain have
speed controls applied.
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With these facts in mind, it seems likely that at some point governments
will intervene in Europe. In the USA, federal legislators have enacted
EPAct which prevents inefficient electrical equipment being supplied.
It is highly unlikely that many in UK industry will embrace energy efficiency
regimes without such government intervention.
It is against this backdrop and with the quest to deliver motor control
to substantially greater numbers of applications that Hitachi's design
team set about the technical developments whose first example is the L100
The internal construction of the new L100 inverter heralds the implementation
of AC motor speed control across a vastly greater number of applications
- in industrial, commercial and domestic markets.
Rather than merely miniaturising the inverter, Hitachi has completely
redesigned the heart of the device. No longer are the intelligent power
module (IPM), CPU, protection diodes and rectifiers discrete components
within the device. Instead Hitachi has developed what is in effect the
first monobloc inverter the Inverter System Power Module (ISPM) .
All that is required to complete the package of the L100 are the capacitors
which form the DC link, an interface and a heat sink.
The ramifications for AC motor control are that these monobloc drives
can be manufactured using high levels of automation, with potentially
huge production volumes and at low cost. Once the inverter becomes cheap
enough, there is every incentive for manufacturers to exploit the speed
and torque control possibilities of the technology.
Ultimately, these new inverters will find their way into increasing numbers
of domestic applications from heating and ventilation pumps to washing