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Technology
Energy-Efficient Hydraulic Lifts
The application of an inverter is not new in the elevator
field. This device has been applied both on traditional
gears as well as on gearless-drive solutions to optimize
performance and power consumption. Designed, manufactured
and guaranteed by Wittur Hydraulic Drives
S.R.L., the new inverter-driven hydraulic-pump unit Wittur
HI combines the performance of inverter technology with
more than 50 years of experience in the field of hydraulic
lift solutions.
The Wittur HI pump unit completes
the range of Wittur Hydraulic Drives’
pump units, including the mechanical
pump unit Wittur HM and the recently
introduced electronic pump unit Wittur
HE. Thanks to its specific configuration,
the Wittur HI pump unit is compliant
with the new EN 81-2 pr.A3
Standards, which will come into force
in 2010.
No additional device or sensor has
to be mounted in the shaft. Everything
is controlled through software that
has been specifically designed for hydraulic
systems. The user interface is
simple, and all adjustments can be
modified using an ergonomic keyboard.
The installer can fine-tune each system
to meet clients’ requirements.
The Wittur HI pump unit integrates
innovative functionalities such as:
◆ Microprocessor adjustment of the
installed power, which can be reduced
to a minimum
◆ Control of all upward and downward car movements
through microprocessor
◆ Minimum oil heating (less than 50% compared to conventional
pump units); in most applications, the cooling
system is no longer necessary.
At the same time, it allows:
◆ Permanent adjustment of the car speed up to 1 mps
◆ Floor leveling accuracy and integrated micro leveling
function.
◆ Operations that are fully independent from cabin load
and oil temperature variation.
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ELEVATOR WORLD India • 4th Quarter 2010 •
Energy Consumption Reduction
European nations, more and more sensitive towards
environmental issues, are distributing ever greater government
and community contributions to promote environmental
sustainability, while citizens take benefit from
an easier investment amortization. The Wittur HI pump
unit controls the car movement through an inverter only,
thereby optimizing the motor efficiency at any given moment
of the lift operation. The value measured in a traditional
pump unit typically varies
between 0.69 and 0.78 (full load)
during motor operation, having a
0.85 data plate. The Wittur HI
pump unit has a constant power
factor of 0.99.
Apart from possible power loss
due to the Joule effect, the power
factor represents the ratio between
the power actually converted
into mechanical functioning
by an electric motor and the
power available from the network.
The so-called reactive power
is instead required to power the
magnetic field of the electric
motor in the hydraulic pump unit.
While minimizing the reactive
power, the use of an inverter increases
the overall system efficiency.
The Wittur HI pump unit offers
electricity savings:
◆ 28% of power utilization
◆ 31% of energy demand from the network
◆ 16% of active energy used for car movement
It is possible to determine the maximum power that
the lift should not exceed by setting the car movement
speed according to the lift system load capacity.
Oil Heating Reduction
The Wittur HI pump unit uses a microprocessor-controlled
motor that reduces oil heating in the tank to a
minimum. The new valve has been designed to allow an
optimum oil flow through the pipes to minimize pressure
drops and to avoid the need for additional cooling sys-