1. Yaskawa Electric America on Variable Torque Loads
Energy Savings
on Variable Torque Loads
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2. Energy Savings: Variable Torque Loads
What is a Variable Torque Load
A load that increases as the speed increases
Examples include Fans and Most Types of Pumps
How can a Yaskawa drive save money
Motor is sized for maximum demand volume at a constant speed
Maximum demand volume is required for small percentage of total operating time
Majority of operating time is spent providing % volume
Affinity Laws
Volume1 / Volume2 = RPM1 / RPM2
Pressure1 / Pressure2 = (RPM1 / RPM2)2
HP1 / HP2 = (RPM1 / RPM2)3
Dropping Motor Speed Increases Energy Savings!
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3. Benefits to Applying Yaskawa Drives to Pumps
Energy Savings
Savings depends on static head of system
Soft Start
Reduces water hammers
Less stress on seals
Noise Reduction
Slower speed = less noise
More Benefits Than Just Energy Savings!
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4. Energy Savings KWH The Proof is in the Calculations!
100,000 sq. ft. building operated 4000 hours per year.
(One 50 HP pump) Based on EPRI procedures for
calculating energy savings from the application of a drive
KWH
The Proof is in the Calculations!
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5. Power Quality and Harmonic Distortion Explanations and Various Countermeasures
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6. What are possible Sources of Harmonics?
Topics
What are Harmonics?
What are possible Sources of Harmonics?
Effects of Harmonics
What Solutions does Yaskawa Offer?
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7. Harmonics Definition
Harmonics are defined as currents or voltages with frequencies that are integer multiples of the fundamental power frequency
SIMPLY PUT - Harmonics are a simple way to describe the shape of a curve that is not sinusoidal.
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8. What is Harmonic Distortion
Harmonic Distortion is a mathematical way of describing how non-sinusoidal a wave shape is
THD = 1.2%
THD = 78.3%
Every Wave shape has Harmonic Distortion!
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9. Impedance has big effect on magnitude of harmonics
Harmonic Basics
Impedance has big effect on magnitude of harmonics
Add 3% impedance ITHD drops by 45%, VTHD drops by 3%
After 7% impedance no effect (dimensing returns).
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10. Possible Effects of Harmonics
Increased Transformer Heating
recommended K-Factor of 9 to 13
Increased Conductor Heating
larger gauge wire
run two wires in parallel
Electromagnetic Equipment
PLCs - more sensitive to Voltage Notching
System resonance - Power Factor Correction
utilize input reactors to reduce likelihood of resonance
Lower Power Factor for System
Harmonic Distortion may have no effect on
Power Distribution Performance
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11. Devices that Increase HarmonicDistortion
Copy Machines
Fax machines
Computers
Elevator Controls
Solid State Lighting Ballasts
Devices that incorporate Static Power Converters - SCRs, Diodes .. etc.
Adjustable Frequency Drives
Common Issue among Common Devices
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12. Different Types of Harmonics
DC Drive - SCR Based
AC Drive - Diode Rectifier
SCR Rectification - Line Notching, Increase Voltage Distortion
Diode Rectification - Pulsed Current, Increase Current Distortion
New Technology May Solve Old Power Quality Problems
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13. Common Specifications
IEEE Focused on Voltage Distortion
IEEE
Focused on Current Distortion
Does not clarify PCC
Does not increase sufficiently
closer to associated device
Custom Specs
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14. Harmonic Countermeasures
Correctly Sized Input Transformer
(Kfactor Rated)
Standard 6-Pulse Front End
DC Link Choke
Standard from 30 Hp to 200 Hp
AC Input Reactor
Optional on All Drives
Custom Designed Trap Filters
12-Pulse Transformer
Optional from 30 Hp thru 1000 Hp
The Solution to fit the Application
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15. Countermeasure Comparison
Power System Distribution Specification
% impedance
100 Hp Linear Load
700 Hp MagneTek Drive Load
Power Distribution Rule of Thumb:
Keep Voltage Distortion Below 5% - Normal Conditions
7.5% Start Up, Unusual Conditions
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16. Standard 6-Pulse Front End DC Link Choke AC Input Reactor
Summary
Standard 6-Pulse Front End
DC Link Choke
Standard from 30 Hp to 200 Hp
AC Input Reactor
Optional on All Drives
Custom Designed Clean Power Filters
12-Pulse Transformer
Optional from 30 Hp thru 1000 Hp
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