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Energy
Savings - AC Inverters Versus
DC Drives Power Factor
 One
big advantage of an AC inverter’s
design is that their capacitors
act as form of built-in power
factor correction. AC inverters
with their respective induction
motors typically have a power
factor of about 0.92-0.95.
A noteworthy characteristic
of an AC inverter is that its
power factor remains consistent
throughout the motor’s
speed range. Conversely, a DC
SCR drive’s power factor
is approximately 0.85 running
at base motor speed and declines
proportionally as motor speed
decreases. For customers that
pay penalties for power factor,
changing to AC drives can offer
significant utility savings.
This is especially evident for
motors that run at slower than
base speed and have heavy loading
like extruder or test rig applications.
Call us for a detailed spreadsheet
that we can apply to your specific
application to show your firm’s
energy saving potential.
Regenerative
AC Drives With 1.0 Power Factor
and Negligible Harmonics
 AC
Drives normally dissipate braking
energy by using dynamic braking
resistors. However, there are
applications where a motor needs
to continuously hold back (i.e.
unwinds, cranes, centrifuges,
windmills, dynamometers, etc.)
or is being mechanically overhauled
(i.e. nip sections on web lines
where the web tension gradients
between adjacent sections make
one section want to pull faster
than the setpoint of the drive).
There are several solutions
for these types of regenerative
AC drive applications. You can
oversize each AC drive’s
DB resistors and the braking
module to allow for a continuous
“burn” of regenerative
energy. Alternately, you can
put drives on a common DC bus
where the overall system shares
the line’s energy, providing
the net sum of the total bus
loading of all the driven sections
is motoring. However, there
is a clean, energy efficient
method to regenerate an AC drive’s
braking power directly back
into the lines as required.
Parker SSD Drives has developed
an Active Front End (AFE) product
designed by application to provide:
- 1.0 power factor without
the need for any power factor
correction equipment
- Elimination of typical drive
harmonics and meets IEEE519
specification for total harmonic
distortion less than below
4%. (Typical issues associated
with plant harmonics are malfunctioning
of microprocessor-based equipment;
overheating in neutral conductors,
transformers, or induction
motors; deterioration or failure
of power factor correction
capacitors; erratic operation
of breakers and relays; pronounced
magnetic fields near transformers
and switchgear.)
- Send regenerative power
directly back to line for
best system energy efficiency
- Eliminate each drive section’s
DB Resistors and Line Reactors
Call us to discuss your AC
drive application. We will be
happy to assist you in helping
you to decide on the best choice
for clean, regenerative AC drive
power!
Parker
SSD Products Catalog and Pricing
 The
Parker SSD Drives Online Product
Catalog has information on AC
and DC drives, AC inverters,
software, the LINK network and
more. Use the link below to
view (left click) or download
(right mouse click and "Save
Target As") the complete
product catalog in electronic
format.
Click
here to view/download SSD Drives
PDF Catalog (1364k)
For complete Word or Excel compatible
Price Lists for Parker SSD Drives
please “Contact Us”
directly. We are interested
in learning more about your
firm so we can provide you with
the most appropriate sales and
service channel for SSD products
in your area.
Parker
SSD On-Line Resource Center
 |
Become
a free member of Parker
SSD Drives On-Line Resource
Center. Simply complete
registration at:
http://www.ssddrives.com/usa/Members/Rc_main_l3.php
Once registered you can
receive valuable information
such as:
- Manuals for all Parker
SSD products
- Software downloads
and free updates
- Application notes
to better assist you
in applying product
software
- Product Bulletins
that give latest technical
announcements
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Spreadsheet
for Calculating Unwind and Winder
Motor HP
 Contact
us to assist you in sizing
your next center winder or unwind
horsepower. We have a detailed
spreadsheet developed by SSD’s
most expert engineers that assists
you in estimating motor horsepower
requirements for winders and
unwinds. This spreadsheet takes
into account such items as material
tension, line acceleration and
deceleration rates, roll inertias,
roll weights, constant torque/constant
horsepower operation, roll build-ups
or build-downs, taper-tension
operation, and gear ratios,
to assist you in specifying
the most appropriate motor power
size for your next unwind or
winder application.
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