Eco Selection Criteria - Size, Type Etc; Overall Considerations; Supply Side Requirements; Supply Tolerance - Siemens MICROMASTER Eco Reference Manual

ECO REFERENCE MANUAL
8.

Eco SELECTION CRITERIA - SIZE, TYPE ETC

Generally, drive selection is straightforward, as the motor rating is already known and the speed range
requirements are either pre-determined, or easily identified and accomplished. However, when a drive
system is selected from first principles, careful consideration may avoid problems in installation and
operation, and may also generate significant cost savings.

OVERALL CONSIDERATIONS

• Make sure that the Current rating of the
inverter is compatible with the name plate
current rating of motor - power rating can be
used as a rough guide.
• Check that you have selected the correct
operating voltage and that the motor terminals
are configured correctly.
• Make sure that the speed range you require is
attainable. Operation above normal supply
frequency (50 or 60Hz) is usually only possible
at reduced power. Operation at low frequency
and high torque (not normally a characteristic
of fans and pumps) can cause the motor to
overheat unless provision is made for
additional cooling.
• Do you need to operate with cables longer
than 100m, or screened or armoured cables
longer than 50m ?. If so, it may be necessary
to de-rate the inverter, or fit a choke to
compensate for the cable capacitance. See
section 14 for motor cable length details.
• The Eco is only intended for use with
centrifugal pumps and fans see p 8-8 for
further information.

SUPPLY SIDE REQUIREMENTS

To achieve maximum reliability and optimum
performance, the main power supply to the
inverter system must be suited to the inverter.
The following points should be considered:
.

SUPPLY TOLERANCE

The inverters are designed to operate on a wide
range of supply voltages as follows:
208 - 240 V +/- 10% i.e. 187-264V
380 - 500 V +/- 10% i.e. 342-550V
525 - 575 V +/- 15% i.e. 472-633V
Inverters will operate over a supply frequency of
47 - 63 Hz
Many supplies vary outside these levels. For
example:
• Supply voltages at the end of long power lines
in remote areas can rise excessively in the
evening and weekends when large loads are
no longer present.
• Industries with locally controlled and
generated supplies can have poor voltage
regulation and control.
• Power systems in certain parts of the world
may not meet the inverter input voltage
tolerances.
In all installations, check that the supply will
remain within the voltage tolerances stated
above. Operation outside of the stated supply
levels may cause damage and give unreliable
operation.
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