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Signal and Power Wiring Considerations
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The document presents an overview of general signal and power wiring considerations when addressing the Electrico Magnetic Compatibility (EMC) concerns for typical commercial and industrial equipment.
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Audible Noise Reduction
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Adjustable frequency drives are commonly installed today
in commercial buildings to provide system control and cost
savings in the heating, ventilating, and air conditioning
(HVAC) systems. In buildings such as hospitals, schools
and dormitories, office buildings and others, audible noise
generated by electrical equipment can be a concern. An
adjustable frequency drive may produce audible noise and
induce noise in motors.
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Automatic Energy Optimization
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Drive manufacturers have attempted to improve the low speed
efficiency of motors with a number of designs. Unfortunately,
most of these products require tedious manual adjustment
and still cannot optimize motor efficiency under all conditions.
The VLT HVAC Drive has a unique control feature called
Automatic Energy Optimization (AEO). With this function, the
drive automatically maximizes motor efficiency under any
operating condition.
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Harmonic Distortion of the AC Power Line
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Commercial HVAC systems are often quite different from
industrial applications. In most HVAC installations, the
adjustable frequency drive shares the AC power supply
with sensitive electronic equipment such as computers,
telecommunications networks, lighting and clocks. When
the HVAC system is in an airport, hospital or research facility, the amount of sensitive equipment increases dramatically.
A possible concern in such environments can be harmonic
distortion on the AC power line generated by the adjustable
frequency drive and other electrical equipment.
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Voltage Vector Control Plus
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The unique Voltage Vector Control, introduced with
the VLT 3500, has been further developed into Voltage
Vector Control Plus (VVC+). VVC+ provides a nearly
sinusoidal output current waveform. This provides
optimum motor magnetization. There is never a need
to derate the motor for full speed, full load applications.
For variable torque applications, there is never
a need to derate the motor for any operational speed.
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