Dynamatic adjustable speed drives and digital controls

Transcription

Lower capital costs
Lower energy costs
Lower ownership costs
Dynamatic TRUE system efficiency
®
“True efficiency” is defined by three important cost factors:
1
Capital Costs – up to 65% less than VFD systems
Capital costs include application engineering,
product procurement, system installation and
commissioning. For typical VFD installations,
added costs can occur in each of these areas
due to system complexity and required ancillary
components such as harmonic mitigation and
system cooling. Compared to these highly
complex variable frequency drive installations,
especially in medium voltage pump applications,
a new Dynamatic system can typically save
municipalities from 50% to 60% on product
procurement costs alone. Dynamatic systems
now feature advanced, yet simple to use, digital
control integration.
• Up to 65% less initial cost than VFDs in medium voltage applications
• Immediate savings of potentially $1M+ on first costs
• No ancillary costs for conditioning/cooling and harmonic suppression
• Lower cost installation and commissioning due to less complex systems
• Advanced yet simple to use digital control integration
• Electronics are 60-70% smaller than comparable medium voltage VFDs
Capital Costs
• Unlike VFDs, medium voltage control occupies a very small footprint
VFDs
Dynamatic
®
Dynamatic drive systems have saved
municipalities hundreds of thousands
of dollars in capital costs, notably in
medium voltage pumping applications,
compared to variable frequency drive
(VFD) installations.
Consider all the costs associated with a pump-drive system
Considerations:
Variable Frequency Drives
Dynamatic® Drives
Total cost of
installation
Varies widely by operating environment
and space requirements; can be extensive
Cooling/air
conditioning
Often required
None required
Power regulation
Recommended
None required
Very large
Small
Electronic footprint
Call Toll Free 800-548-2169
(US / Canada)
+1-262-554-7977 (Outside US) www.dynamatic.com
Up to 65% lower than VFDs in 4160VAC
and 2300VAC installations; comparable
primary equipment costs in 480VAC and
575VAC installations
2
Energy Costs – lowest for wastewater pumping applications
The operating efficiency of a Dynamatic® drive
increases relative to the normal operating speed
of a motor. This makes the Dynamatic drive ideally
suited to most wastewater pumping applications,
which typically require controlled speed within
the range of from 75% to 100% of the motor’s
rated speed. In contrast, the operating efficiency
of a variable frequency drive decreases across this
range. In addition, VFD operating efficiency can be
further diminished by added energy costs incurred
by required ancillary VFD system components.
• Most wastewater pumping applications require 75-100% rated speed
• Dynamatic drives use less energy to operate in these applications than VFDs
• Unlike VFDs, you do not pay for required cooling and harmonic protection
• Digital closed-loop control uses less than 1% of the total AC input current to the motor
• Lower peak demand costs: no multiple, medium voltage motor starting and stopping
• No ancillary equipment energy consumption such as external cooling and harmonic mitigation
• Capable of continuous operation in 40° C ambient temperature
Dynamatic® vs. VFD – kWh usage for 500HP 880RPM motor
Dynamatic electromagnetic drive efficiency
is ideally suited to wastewater pumping
applications, which typically require from
75% to 100% motor speed regulation to
move water. When operating efficiency is
factored along with medium voltage first
costs and lifetime ownership costs, total
savings are often dramatic compared to
variable frequency drive installations.
Formula: Savings = kW difference x hrs x kW hour rate
Example @ 90% output speed,12 hours per day, $.08 per kWh:
Efficiency difference = VFD kW – Dynamatic kW = 410 – 390 = 20 kW
Dynamatic yearly savings = 4380 hrs x .08 x 20kWh = $7008
Consider all the benefits of higher overall system operating efficiency
Considerations:
Long-term reliability
3-5 year manufacturing run, planned
obsolescence
Dynamatic® Drives
20-40 year average life of mechanical
components; 15-20 year control life
Optimum efficiency
at 75-100%
operating speed
NO
YES
Ancillary equipment
energy usage
YES
NO
(US / Canada)
+1-262-554-7977 (Outside US) www.dynamatic.com
3
Ownership Costs – greatly reduced maintenance, repairs and upgrades
For decades, Dynamatic® drives have outlasted variable
frequency drives in a wide range of wastewater
applications. In fact, Dynamatic drives have
been shown to outlast VFDs by as much as
6:1. Their rugged and reliable electromagnetic
clutch design is highly tolerant of fluctuations in
power quality. Unlike VFDs, Dynamatic systems
produce virtually no harmonic noise into your
plant’s electrical system or onto the utility grid.
By comparison, VFDs continue to be complex
devices bearing higher ownership costs with shorter
product life cycles. These significantly higher costs
are attributable to quicker VFD product series
obsolescence, faster parts obsolescence and earlier
forced product replacements.
• Proven rugged and reliable electromagnetic clutch design
• Systems have outlasted VFDs by as much as 6:1
• Easy to maintain by on-site staff using low-cost parts
• Service and repair can often be performed by maintenance staff
• Unaffected by power quality fluctuations that can destroy VFDs
• Unlike VFDs, no annoying audible whine enters the work environment
• Produce virtually no harmonic distortion into your electrical system or power grid
Consider the costs over the lifetime of ownership
Considerations:
Dynamatic® Drives
Harmonic noise / RF interference
Extensive
None
Long-term cost of operation
Can be extensive
Minimal
Line voltage sensitivity
Extensive
Minimal
Heat / cold sensitivity
Extensive
Minimal
Upgradable to new components
Limited
Available
Cost of replacement parts
Can be high, if available
Low
Replacement parts availability
Limited, if at all after 5-8 years
Excellent: 40+ year manufacturing period
Service and repair
Complex (by factory personnel)
Simple (by customer)
Inter-brand support
NO
YES
Downtime if problems with electronics
Can be weeks or months
Minutes (simple component swap-out)
Dynamatic adjustable speed drives and controls are easy for
wastewater plant maintenance staff to keep up and running.
The rugged and reliable drives have been proven to outlast
VFDs by as much as 6:1.
Simply better by design
AC Motor
Digital Clutch Controller
Input Bearing
Input Drum
Output Rotor
Operator
Station
Air Gap
Clutch Coil
Tachometer
Output Bearing
Dynamatic Electromagnetic Drive Technology
®
The Dynamatic adjustable speed drive system consists of a constant speed AC induction
motor and an electromagnetic clutch, governed by a small digital controller.
Dynamatic allows the AC motor to run at its optimum rated speed. A simple
electromagnetic coupling (clutch) is used to vary the output speed.
The only wear parts are bearings and brushes, since the motor and drive are
separated by an air gap. By regulating voltage to the clutch coil, a magnetic
flux field is generated in the gap and distortion of the flux field creates
torque. Output speed is governed by the digital control. The greater
the power to the clutch coil, the greater the strength of the
magnetic flux field, and the greater the output torque/speed.
The feedback signal from the tachometer is compared to a
reference signal within the controller to maintain accurate
speed within 0.5%. This closed-loop speed system typically
uses less than 1% of the total AC input current to the motor.
Dynamatic® adjustable speed drives and controls
Dynamatic® Drives
•NEW electromagnetic adjustable speed drives
•Horizontal and vertical drive systems up to 4,000 HP
•Original Dynamatic® and Eaton Dynamatic® brand parts
•Factory remanufactured drives and controllers
•Two-year factory warranty
•Made in USA
Dynamatic® Controls
• NEW! EC-2000 Digital Control for new installations or
retrofit of all brands of eddy-current drives
•Simple, versatile, digital, electromagnetic drive control
•PLC and SCADA compatible
•Local and remote access to preprogrammable run presets
•Outputs do not require separate external DC supply
•RS232, RS422 or RS485 serial connections
•Small and compact – typically fits most existing motor
control enclosures
•Made in USA
Services
•OEM parts, repairs and replacement
•Adjustable speed drive system engineering and startup support
•Custom-engineered electromagnetic digital control upgrades
•24-hour hotline: 1-800-548-2169
•All products and systems 100% factory tested
•Including original Dynamatic OEM specifications
Other products and services...
•AC and DC motors
•Custom engineered controls
•Gear motors and speed reducers
•Water-cooled clutches and brakes
•Rebuilds and refurbishments
MADE IN THE U.S.A.
Contact us for new system solutions, parts and service:
Phone:1-800-548-2169
Email:[email protected]
Website:www.dynamatic.com
7900 Durand Avenue | P.O. Box 0361 | Sturtevant, Wisconsin 53177 USA
800-548-2169 (US/Canada) | +1-262-554-7977 (Outside US/Canada) | www.dynamatic.com
© 2012 Drive Source International, Inc.
Dynamatic® EC 2000 digital controls
Panel Mount with optional keypad kit
with cable and mounting hardware
NEMA 1 or NEMA 12 enclosure
complete with keypad and readout
Cost-effective speed control replacement for all Eddy Current drives and brakes up to 6,000 HP
• Parameters allow for fine-tuning of the operation for maximum performance.
• Simple, rugged and compact design with a long life
cycle for overall reliability.
• Independently adjustable acceleration / deceleration
with timed braking delay after stopping.
• No need for air conditioning or harmonic suppression.
• Set point flexibility makes interfacing with a computer
system or a programmable logic controller easy.
• Allows different size drives to be controlled with a
single control. Reduces parts and control inventory
requirements.
EC 2000 replaces all brands of Eddy Current
controls, including:
•
•
•
•
EM (Electric Machinery) • Eaton Dynamatic
US/WER (Emerson)
• Louis Allis
Ideal Electric
• Hitachi
Galco
• Unaffected by power quality fluctuations that can
destroy variable frequency drives.
• Process signal interface capability.
• New factory warranty / extended warranties available.
• 24-hour factory service, start-up, application support.
New dimensions in Eddy Current control
Dynamatic® EC 2000 delivers precision and flexibility
Now you can control the speed of Eddy Current drives within 0.1% from no load
to full load. Receive 250% rated torque for starting and momentary overload
conditions. When compared to drives offering only 110-150% starting torque,
you may be able to use a smaller, more economical drives.
100% tested
All Dynamatic® controls and drives are 100% load tested before they leave our
factory ensuring reliable startup and performance.
Easy installation
Available in 115 volt, single phase, 50/60 Hz input power to simplify
worldwide applications. Requires only 1% of line power, allowing
installation up to 500’ from the drive.
PLC compatibility
Interfacing with existing PLC systems is a snap. Interface directly with
computer controlled systems. Interchangeable with a wide range of
drive horsepowers, reducing your inventory needs.
Standard functions of the Dynamatic® EC 2000 digital control:
Instrument signal follower permits control from all common
process inputs.
Open collector outputs permit interface of control alarm and
annunciation with real world devices.
Dual, programmable on-board power relays for customer
interface.
Up to four preset speeds can be selected from the softouch
keypad or terminal strip permitting operation at predetermined
optimum set points.
Auto restart after power outage provides true “2-wire”
control for applications requiring unattended restart.
PLC run/stop functions via the built-in 2-wire scheme permit
control through terminal strip.
Automatic and manual functions through terminal strip or
softouch keypad permit process control or normal operation for
startup and adjustment.
Local and remote functions through softouch keypad allow
control from multiple operator devices.
Programmable jog speed can be actuated through terminal
strip or softouch keypad for application flexibility.
Speed mode or torque mode flexibility. Speed mode is
for closed loop systems utilizing tachometer feedback for precise
speed control. Torque mode is for applications where torque is
regulated variable rather than speed. In torque mode the control
operates by closing only the current loop and regulates torque
output of the drive.
Analog output signals can be programmed to provide signal
proportional to critical parameters (e.g., speed, current or voltage).
Linear acceleration and deceleration function permits
soft start and stop control.
Optional features:
Dancer position without Mutuatrol® adjusts drive speed
to maintain position of the dancer. Dancer applies tension to the
material. Position is set by operator’s reference potentiometer.
Mutuatrol® is for drives with an adjustable torque brake, allowing
the drive and the brake to be mutually regulated. Primary purpose
is accurate speed control using driving or braking as required.
Adjustable braking is included.
Load sharing for multiple drive applications using a single control.
(US / Canada)
+1-262-554-7977 (Outside US/Canada) www.dynamatic.com
24-hour support, on-site service and training
DRIVE SOURCE INTERNATIONAL, INC.
7900 Durand Avenue, P.O. Box 0361 Sturtevant, Wisconsin, U.S.A. 53177 Tel: 262-‐554-‐7977 Fax: 262-‐554-‐7041 E-‐Mail: [email protected] World's leading manufacturer of Eddy Current adjustable speed drives, brakes and controls
www.dynamatic.com
1-800-548-2169 (US / Canada)
+1-262-554-7977 (International)
INSTALLATION COMPARISON CONSIDERATIONS FOR PUMP AND FAN DRIVE SYSTEMS Considerations Cable Length External Cooling Harmonic Mitigation VFD Dynamatic® 50 feet 200 feet Most VFD manufacturers recommend no more than 50 feet from the VFD output to motor termination, due to inductance [1]
and EMI interference Factory recommended length up to 200 feet (transmitting only DC voltage) before requiring increase in wire size Forced Air HVAC or Water Cooling Ambient air Switching losses in VFDs create heat which must be mitigated through external cooling methods. Total switching losses equal less than 1
10 % of total system power. Input Isolation Transformer Input Isolation Transformer Limits current to drive and mitigates harmonic interference to peripheral equipment 6KVA, 575VAC included in all Dynamatic® controls [1]
Input Line Reactor [1]
Noise mitigation on input side of drive Output Harmonic Filters None Required None Required Used to reduce the amplitude of fixed frequency currents to prevent them from [1]
entering the rest of the system Installation Cabling Factory Recommended None Required Special consideration must be given to the proper installation and operation of the overall system that comprises the VFD, the motor it controls, and the cable that connects them. The way in which VFD-‐based systems are constructed and operated will have an impact on both the longevity and reliability of all the components of the system, as well as [2]
nearby or adjacent systems. System Grounding Factory Recommended No specialty cable requirements, only national electrical code standards apply. None Required Complex grounding system due to Pulse [2]
Width Modulation No specialty grounding requirements, only national electrical code standards apply. Reliable adjustable speed solutions engineered for your application.
DRIVE SOURCE INTERNATIONAL, INC. 7900 Durand Avenue, P.O. Box 0361 Sturtevant, Wisconsin, U.S.A. 53177 Tel: 262-‐554-‐7977 Fax: 262-‐554-‐7041 E-‐Mail: [email protected] INSTALLATION COMPARISON CONSIDERATIONS FOR PUMP AND FAN DRIVE SYSTEMS (CONTINUED) Motor Considerations VFD Dynamatic® Requirements for Inverter Duty Motor Factory Recommended None Required Pulse Width Modulation can cause voltage transients well above the rated voltage of the motor which can lead to failure of the insulation system in a very short period of time.[1] Standard Class F insulated, Design B motors Brand Flexibility Factory Recommended Non-‐exclusive Motor manufacturers limit warranty to select, pre-‐tested VFDs. Dynamatic® systems are compatible with all motor manufacturers. Applicable None required Bearing Protection Anti-‐Ratcheting “Shaft currents” which flow as a result of shaft-‐to-‐frame electrical potentials. A major source of the “shaft current” in this class of bearing failure is the potential induced between the rotating element and static element in variable speed electric motors, this potential is associated with the use of solid state gating devices used to generate DC current for DC motors or AC variable [3] frequency (VFD) power for AC motors.
Installation of shaft bearing protection highly recommended. Due to absence of shaft currents Available Option Available Option Reliable adjustable speed solutions engineered for your application.
DRIVE SOURCE INTERNATIONAL, INC. 7900 Durand Avenue, P.O. Box 0361 Sturtevant, Wisconsin, U.S.A. 53177 Tel: 262-‐554-‐7977 Fax: 262-‐554-‐7041 E-‐Mail: [email protected] References 1. Natural Resources Canada (2009). 4 Selection of VFD Drives. Published by Natural Resources Canada. 2. Shuman, B. (2009). Building a Reliable VFD System. Published by Belden, Inc. 3. Boyanton, H. (2010). Bearing Damage Due to Electric Discharge: Electrical Discharge Due to Machining of Bearings. Published by Shaft Grounding Systems: Albany, OR. Reliable adjustable speed solutions engineered for your application.
If you are considering one of those “rare-earth”
magnetic couplings for your adjustable speed drive
applications, start by comparing the facts. You will
quickly see why Dynamatic® adjustable speed drives
and digital controls define TRUE system efficiency.
Compare the facts:
“Rare-earth” magnetic
coupling design
Dynamatic® Drive System
Product awareness and history:
Relatively unknown...
introduced in 1999, with
only 5000 installations.
A well-known brand since
1931... Dynamatic® has over
200,000 installations.
New installation or retrofit:
Mechanical installation,
(mechanical actuator only).
Interface with PLC requires
additional signal converter.
Simple 4-wire connection from
electro-magnetic coupling to
digital control. PLC integration
through onboard input and
output signals.
Ease of system integration:
Incomplete system, limited
through ancillary options.
Complete system with wide
range of easy-to-use digital
control options.
Retrofit existing eddy-current installation:
Requires major system overhaul. No capital cost savings.
Simple digital control upgrade.
Drive cooling:
Requires water cooling
above 400HP, based on RPM.
Air-cooled design.
Affects of poor power quality:
Minimal impact.
Unaffected.
Harmonic noise / electromagnetic interference:
Electromagnetic interference
a factor if unit disassembled.
None.
Durability:
Stated lifespan 15-30 years.
Proven lifespan 40+ years.
Energy-saving rebate incentives:
May be compatible.
May be compatible.
Can be installed indoors & outdoors without
special considerations:
Yes.
Yes.
Worldwide EASA Motor repair center support:
No.
Yes.
Energy savings:
Similar savings to VFDs due
to pump affinity laws.
Greater savings than VFDs
due to pump affinity laws.
Inter-brand support:
No.
Yes.
Replacement parts availability:
Limited, expensive.
Excellent: 40+ year
manufacturing period.
MagnaDrive-comparison.indd 1
9/12/12 2:27 PM
Only Dynamatic® offers
complete systems... featuring
new easy-to-use digital controls
• Onboard, multiple input and output signals as standard
• Built-in adjustable acceleration and deceleration controls
• Standard built-in process protection
• One manufacturer, one package, one solution
Compare the capital costs* in the following examples:
*Competitive price comparisons based on comparable H.P. and RPM specifications, distributor quotations on rare-earth magnet drives, and motor manufacturer list prices.
Example 1:
Example 2:
Rare-earth magnetic coupling ASD
400HP/1800 RPM, Air Cooled, Vertical Installation:
ASD cost: $86,000.00 + Motor cost: $78,000.00
Total capital cost = $164,000.00
400HP/720 RPM, Water Cooled, Vertical Installation:
Dynamatic® Model 8161
(includes 400HP/1800RPM Motor and EC-2000 HPP Control)
Package capital cost = $130,000.00
Dynamatic will save you $34,000.00 in capital costs
Example 3:
Example 4:
1000HP/1800 RPM, Air Cooled, Vertical Installation:
1000HP/720 RPM, Water Cooled, Vertical Installation:
Compare the energy costs (RAS pump power usage):
Power(kW)
40
P43403 Dynamatic® drive
P43403 magnetic coupling
30
20
10
0
0
2
4
Flow (MGD)
6
MagnaDrive-comparison.indd 2
8
Energy usage comparison based on
independent study conducted by the
Sacramento Regional Water Authority
9/12/12 2:27 PM
Case Study: TRUE System Efficiency
Dynamatic® drives with digital controls instead of VFDs
Location: Lemay Pump Station, St. Louis, MO
Challenges: The need for faster and easier drive
system controls, including distributed control and SCADA
integration, prompted Lemay Pump Station management
to consider alternative systems, such as the latest variable
frequency drives on the market. However, as management studied the challenge further, the conversion from
Dynamatic® drives to VFDs posed a significant range of
added costs. This compelled the municipality to more
carefully evaluate their application requirements.
Photo courtesy Lemay Pump Station
Results: When a cost/performance evaluation was
conducted across the municipality’s 200HP and larger
electromagnetic pump-drive systems, management
determined that these applications would be best
served by upgrading all existing Dynamatic® drives from
analog-based controls to new digital controls. Specific
cost advantages for the controls upgrade have included
the avoidance of VFD capital costs and installation costs
ranging into hundreds of thousands of dollars. The
municipality reports that since the upgrade began in
2006, the Dynamatic drives have continued to reliably
meet pump station performance needs, with the added
advantage of digital programming and monitoring.
Vince Stollhans, Assistant Manager
Pump Station Division/Instrumentation
Photo courtesy Lemay Pump Station
Background: Dynamatic® electromagnetic adjustable
speed drives have performed for over two decades in
higher horsepower wastewater pumping applications.
By upgrading a drive’s original control from analog
to digital, municipalities are combining proven drive
reliability and economy with advanced, digital system
programming and monitoring.
User Comments:
“We have eddy-current drives that are fifty
years old and I have never replaced one with
a VFD. It’s a simple device and that’s why the
clutch lasts a long time. Adding to that, the
new digital controls we have purchased have
been reliable, compact and cost-effective.”
Trained as an electrical engineer, Vince Stollhans is a pump station
instrumentation manager who is keenly interested in finding
practical, cost effective ways to apply technology to wastewater
process improvement. For several non-submersible, higher horsepower pumping applications, Stollhans has sought to reduce
capital costs and installation costs by upgrading the pumping
station’s Dynamatic eddy-current drives to digital controls.
“When we evaluate replacing an eddy-current clutch with a
variable frequency drive, we do not want to replace a technology
that works. So we look at the application. For dry pit pumping
applications, especially where we don’t have 24-hour operation, we’ve looked at our technology options versus the existing
eddy-current clutch. To begin with, a VFD requires more physical
space. A larger horsepower VFD can take up ten feet of space,
versus fitting into a cabinet. Removing the eddy-current clutch
and re-coupling the motor is another expense. For a particular
application, we may be talking about a $30,000 to $80,000 VFD,
versus a $5,000 digital control upgrade. The total cost for time
and material could be $50,000 to $80,000 versus $10,000 to
$15,000 per unit. This is in the range of 200 to 700 horsepower,
up to 4160 volt.
“The objective, in the long run, is for us to modernize a process,
increase reliability, make it available and get the information we
need,” Stollhans said.
Dynamatic® Drives: How they work
A VFD uses AC-to-DC voltage conversion, high-frequency
sampling, and a powerful inverter in a large electronics rack
to alter the speed of and to supply the operating voltage to
an AC motor. A Dynamatic® drive uses eddy-current technology consisting simply of a constant speed AC induction motor
and a magnetic clutch speed driven by a small analog or digital
controller. The clutch uses an eddy-current coupling to vary the
speed of an attached output shaft. DC voltage applied to a field
coil in the clutch produces a magnetic field, which generates an
attracting force to the inside of a hollow iron drum. The amount
of power available is determined by the size of the motor, which
can range from relatively small to motor, 4000 HP or more.
Up to 65% lower capital pump-drive system costs
Considerations:
Variable
Frequency Drives
Dynamatic®
Drives
Total cost of
installation
Varies widely by
operating environment and space
requirements; can
be extensive
Up to 65%
lower than VFDs
in 4160VAC and
2300VAC installations; comparable
primary equipment
costs in 480VAC
and 575VAC
installations
Cooling/air
conditioning
Often required
None required
Power regulation
Recommended
None required
Very large
Small
Efficiency Considerations:
At maximum clutch coupling, the total efficiency for Dynamatic
drives is just below that of the motor alone. A Dynamatic drive’s
control unit supplies voltage to the clutch’s coil and only requires
2% or less of the drive’s total power. As the process speed
reduces, the losses in an eddy-current clutch rise in proportion
to the slip. Relative to VFDs, this creates an efficiency crossover
point between 75% and 80% of motor base speed. Above this
crossover point, the Dynamatic drive is more efficient. Below this
point, the VFD makes up for its initially higher control losses and
becomes the better efficiency choice.
Higher overall system operating efficiency
Variable
Frequency Drives
Dynamatic®
Drives
obsolescence
20-40 year average
life of mechanical
components; 15-20
year control life
Optimum efficiency
at 75-100%
operating speed
NO
YES
Ancillary equipment
energy usage
YES
NO
Considerations:
Dynamatic Drive Advantages:
Dynamatic drives have an inherent long-term reliability advantage and function well in both adverse operating conditions
and remote locations. Cooling, power management, and
maintenance are minor and include only those service processes
required for stand-alone AC induction motors. For systems that
operate at 75 to 80% of base speed or higher a majority of the
time, better efficiency is also a benefit.
Parts interchangeability and the availability and ease of replacements and upgrades make Dynamatic drives a great long-term
investment. Maintenance costs are low and can be completed
by facility staff.
For more information, visit www.dynamatic.com
800-548-2169 (US/Canada) or +1-262-554-7977 (Outside US)
Lowest lifetime cost of ownership
Considerations:
Variable
Frequency Drives
Dynamatic®
Drives
Harmonic noise /
RF interference
Extensive
None
Long-term cost
of operation
Can be extensive
Minimal
Extensive
Minimal
Extensive
Minimal
Upgradable to new
components
Limited
Available
Cost of replacement
parts
Can be high, if
available
Low
Replacement parts
availability
Limited, if at all
after 5-8 years
Excellent: 40+ year
manufacturing
period
Service and repair
Complex (by factory
personnel)
Simple
(by customer)
Inter-brand support
NO
YES
Downtime if problems
with electronics
Can be weeks
or months
Minutes
(simple component
swap-out)
Ask for a FREE system evaluation.
Application-engineered Systems: Drives, Brakes and Controls
Phone: 800-548-2169 (US/Canada) | +1-262-554-7977 (Outside US) | www.dynamatic.com
Case Study: TRUE System Efficiency
Why This Municipality Chose Dynamatic® over VFDs
Location: St. Joseph, Missouri, Water Protection
Background: Dynamatic® drive clutches on induction
motors have been installed in wastewater treatment
applications for many decades, primarily due to the
inherent durability, simplicity, and reliability of eddycurrent technology. Variable frequency drives (VFDs)
gained popularity in the 1980s (see page two for a
technical comparison). Real‐world experience at
St. Joseph Water Protection provides fact-based results
comparing the advantages and disadvantages of each
pump drive system.
Challenges: The St. Joseph system receives power
from a generating station on the Missouri River,
and line output experiences occasional fluctuations.
The operating environment can be harsh, with wide
temperature and air quality variations.
Results: 15 VFDs were installed in 1979, during
a system expansion, to complement existing eddycurrent drives. Over the ensuing three decades, all
of the VFDs have been replaced multiple times at
a cost of several million dollars. Maintenance and
replacement costs on the VFDs have been high.
Long‐term reliability and factory support have been
inferior. All original eddy-current drives, installed in
the Sixties, continue to be operational. Annual maintenance costs for the eddy-current drives are very low.
The City of St. Joseph is replacing their VFDs with
Dynamatic eddy-current drives, and all new variable
speed applications will specify Dynamatic drives.
User Comments:
“We currently have six eddy-current drives
that have been running nonstop since 1965.
We have never lost one. I’ve lost so many VFDs
over the past 30 years that it’s not even funny.
“We had a situation where multiple 300 horsepower VFDs that
were only a year-and-a-half old went Poof!, and we had to explain
to the Missouri Department of Natural Resources why we were
bypassing wastewater treatment for a week. The VFD maker didn’t
address over-voltage issues, even small ones, with a fail-safe.
Eddy-current drives don’t have any of those problems, as there
are no high voltage electronics in front of the motors.
“We’ve done an annual cost and reliability evaluation of our
different pump and air handling drives. The cost of maintaining
our existing eddy-current drives is ridiculously low, like $40 a year
for brushes. Once every two to three years, we soapstone clean
the contacts, and that’s it. We’ve spent millions on replacing
VFDs, however.
Don Gilpin, Superintendent of Wastewater Treatment
“Although VFDs are known to be more efficient at speeds less
than 75%, eddy-current drives are as good or better at normal
operating speeds. If a system is sized correctly, its pumps should
be operating above 80% anyway. I’ve had extensive conversations
with engineering firms about efficiency and proper system design.
I’ve come to the conclusion that VFDs sounded like a great idea
when they came out 30 years ago, but now, after decades of
operation and experience here, we’re realizing that their main
selling point – efficiency – doesn’t reflect reality.”
Dynamatic® Drives: How they work
A VFD uses AC-to-DC voltage conversion, high-frequency
sampling, and a powerful inverter in a large electronics rack
to alter the speed of and to supply the operating voltage to
an AC motor. A Dynamatic® drive uses eddy-current technology consisting simply of a constant speed AC induction motor
and a magnetic clutch speed driven by a small analog or digital
controller. The clutch uses an eddy-current coupling to vary the
speed of an attached output shaft. DC voltage applied to a field
coil in the clutch produces a magnetic field, which generates an
attracting force to the inside of a hollow iron drum. The amount
of power available is determined by the size of the motor, which
can range from relatively small to motor, 4000 HP or more.
Up to 65% lower capital pump-drive system costs
Considerations:
Variable
Frequency Drives
Dynamatic®
Drives
Total cost of
installation
Varies widely by
operating environment and space
requirements; can
be extensive
Up to 65%
lower than VFDs
in 4160VAC and
2300VAC installations; comparable
primary equipment
costs in 480VAC
and 575VAC
installations
Cooling/air
conditioning
Often required
None required
Power regulation
Recommended
None required
Very large
Small
Efficiency Considerations:
At maximum clutch coupling, the total efficiency for Dynamatic
drives is just below that of the motor alone. A Dynamatic drive’s
control unit supplies voltage to the clutch’s coil and only requires
2% or less of the drive’s total power. As the process speed
reduces, the losses in an eddy-current clutch rise in proportion
to the slip. Relative to VFDs, this creates an efficiency crossover
point between 75% and 80% of motor base speed. Above this
crossover point, the Dynamatic drive is more efficient. Below this
point, the VFD makes up for its initially higher control losses and
becomes the better efficiency choice.
Higher overall system operating efficiency
Variable
Frequency Drives
Dynamatic®
Drives
obsolescence
20-40 year average
life of mechanical
components; 15-20
year control life
Optimum efficiency
at 75-100%
operating speed
NO
YES
Ancillary equipment
energy usage
YES
NO
Considerations:
Dynamatic Drive Advantages:
Dynamatic drives have an inherent long-term reliability advantage and function well in both adverse operating conditions
and remote locations. Cooling, power management, and
maintenance are minor and include only those service processes
required for stand-alone AC induction motors. For systems that
operate at 75 to 80% of base speed or higher a majority of the
time, better efficiency is also a benefit.
Parts interchangeability and the availability and ease of replacements and upgrades make Dynamatic drives a great long-term
investment. Maintenance costs are low and can be completed
by facility staff.
For more information, visit www.dynamatic.com
800-548-2169 (US/Canada) or +1-262-554-7977 (Outside US)
Lowest lifetime cost of ownership
Considerations:
Variable
Frequency Drives
Dynamatic®
Drives
Harmonic noise /
RF interference
Extensive
None
Long-term cost
of operation
Can be extensive
Minimal
Extensive
Minimal
Extensive
Minimal
Upgradable to new
components
Limited
Available
Cost of replacement
parts
Can be high, if
available
Low
Replacement parts
availability
Limited, if at all
after 5-8 years
Excellent: 40+ year
manufacturing
period
Service and repair
Complex (by factory
personnel)
Simple
(by customer)
Inter-brand support
NO
YES
Downtime if problems
with electronics
Can be weeks
or months
Minutes
(simple component
swap-out)
Ask for a FREE system evaluation.
Application-engineered Systems: Drives, Brakes and Controls
Phone: 800-548-2169 (US/Canada) | +1-262-554-7977 (Outside US) | www.dynamatic.com

Dynamatic adjustable speed drives and digital controls

Transcription

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