AAFAME Presentation Scott D.Holdridge Shermco Industries Inc. Drives and Automation Application, Sales and Service Manager, Irving Texas. 1
What we are going to cover in this Presentation Motor Efficiency-NEMA Definitions Applying VFD to NEMA Motors Saving Money- Motors/Drives Fiscal Payback- Infinity Laws 10 Questions for Drive Applications Application Considerations & Q/A s 2
NEMA Trade Association Information NEMA is the trade association of choice for the electrical manufacturing industry. Founded in 1926 and headquartered near Washington, D.C., its approximately 450 member companies manufacture products used in the generation, transmission and distribution, control, and end-use of electricity. 3
Exploded Motor View: TEFC NEMA Design Electric Motor 4
Subject: The Dumb, Energy Using Electric Motor 5
General Industry Electric Motor Energy Nameplate Labeling NEMA Premium Efficient NEMA MG-1 NEMA Energy Efficient /EPACT NEMA MG-1 High Efficiency Standard d Efficiency Definite Purpose Motors Additional Labeling: Inverter Duty Motors 6
Example of Premium Efficiency Motor VFD Capabilities and Speed Turndown Specifications from a Major Manufacture s Industrial Motor Catalog. VFD service Capability. Inverter Duty motors utilize a class F insulation system designed for peak voltages of PWM waveform application. Designed to meet and exceed NEMA MG1 Part 31 requirements at either 460V or 575V. Choose between zero to base speed variable torque; 4:1, 6:1, 10:1 or 1000:1 constant torque. Parameters are included in a detailed variable speed design nameplate. Use whenever NEMA Part 31 is required, for quality and reliability. That s why every motor is backed by a three-year warranty for this design. 7
Example of a Typical NEMA Premium Efficiency Motor Nameplate, Note: Nom, Eff. 8
Example of NEMA Premium. Eff. Chart FULL-LOAD EFFICIENCIES FOR 60 HZ NEMA PREMIUM EFFICIENCY ELECTRIC MOTORS RATED 600 VOLTS OR LESS (RANDOM WOUND) 1-125 HP ------TEFC ENCLOSED MOTORS (Data Based From IEEE 112 Method B Testing For Manufactures) 2 POLE 4 POLE 6 POLE HP Nom. Eff. Min. Eff. Nom. Eff. Min. Eff. Nom. Eff. Min. Eff. 1 77.0 74.0 85.55 82.5 82.5 80.00 1.5 84.0 81.5 86.5 84.0 87.5 85.5 2 85.5 82.5 86.5 84.0 88.5 86.5 3 86.5 84.0 89.5 87.5 89.5 87.5 5 88.5 86.5 89.5 87.5 89.5 87.5 7.5 89.5 87.5 91.7 90.2 91.0 89.5 10 90.2 88.5 91.7 90.2 91.0 89.5 15 91.0 89.5 92.4 91.0 91.7 90.2 20 91.0 89.5 93.0 91.7 91.7 90.2 25 91.7 90.2 93.6 92.4 93.0 91.7 30 91.7 90.2 93.6 92.4 93.0 91.7 40 92.4 91.0 94.1 93.0 94.1 93.0 50 93.0 91.7 94.5 93.6 94.1 93.0 60 93.6 92.4 95.0 94.1 94.5 93.6 75 93.6 92.4 95.4 94.5 94.5 93.6 100 94.1 93.0 95.4 94.5 95.0 94.1 125 95.0 94.1 95.4 94.5 95.0 94.1 9
NEMA -National Electrical and Medical Manufactures Association i :Presentation References NEMA-Motor Eff. IEEE112 Method B Testing Procedure and NEMA MG1- Part 31 Inverter Duty Definitions http://www.nema.org NEMA Application Guide For Ac Adjustable Speed Drives 2007 US Government -EPACT 10
What is a VFD? A (VFD) Variable Frequency Drive or DC Drive is like the Gas Peddle on a car, with the AC/DC Motor being the car engine It adjusts the speed of a motor, based on demand, with the added benefit to save energy and prolonging motor and mechanical component life Without a VFD, a motor is either on at full speed, or off period. A VFD/DC Drive eliminates the initial power surge and mechanical shock of switching the motor from 0% to 100% Voltage/Current, just like a soft start. A VFD conserves energy when the control system senses that the motor can meet process needs at lower speed, while running at less than 100% power. 11
How Does A VFD Work? It changes the speed of an AC motor by adjusting or varying the frequency and voltage Typical frequency-voltage adjustment range from 10-60Hz AC and 80-480V- 3 Phase However this can be increased up-to 400 Hz Proportional changes in the Frequency and Voltage, change motor output speed. Example : Same 1800 RPM Motor, 3 Frequency Settings 1800 RPM AC Motor at 60HZ/480V Setting. 900 RPM AC Motor at 30HZ/230V Setting. 450 RPM AC Motor at 15HZ/115V Setting. 12
VFD s What and Why s What Adjustable Speed Controlled Starting Controlled Stopping Why Standard AC Motor Energy Savings Improved Process Control Remote and/or Automated Control Reduced Inrush Current Less Power Line Disturbance. Improved Process Control Reduced d Shock Loading Reduced Maintenance Increased Equipment Life Improved Safety Improved Process Control 13
V/T Vs./T Applications Examples Variable Torque Vs. Constant Torque Variable speed drives, and the loads they are applied to, can generally be divided into two groups: constant torque and variable torque. The energy savings potential of variable torque applications is much greater than that of constant torque applications. Variable torque loads include centrifugal pumps and fans, which make up the majority of HVAC applications. Constant torque loads include vibrating conveyors, punch presses, rock crushers, machine tools, and other applications where the drive follows a constant V/Hz ratio 14
Why Variable Speed Energy Savings Why Variable Torque Loads Offer Greatest Energy Savings In variable torque applications, the torque required varies with the square of the speed, and the horsepower required varies with the cube of the speed, resulting in a large reduction of horsepower for even a small reduction in speed. The motor will consume only 25% as much energy at 50% speed than it will at 100% speed. This is referred to as the Affinity Laws, which define the relationships between speed, flow, torque, and horsepower. If you have an AC motor-driven application that does not need to be run at full speed, then you can cut down energy costs by controlling the motor with a variable speed drive (VFD, aka variable frequency drive). Variable speed drives allow you to match the speed of the motor-driven equipment to the process requirement. There is no other method of AC motor control that allows you t o accomplish this. 15
Affinity Laws Affinity Laws The effects that reduced speed has on a variable torque fan are summarized by a set of rules known as the Affinity Laws. The basis interpretation of these laws is quite simple: 1. Flow produced by the device is proportional to the motor speed. 2. Pressure produced by the device is proportional to the motor speed squared. 3. Horsepower required by the device is proportional to motor speed cubed. For instance, a variable speed drive running a variable torque load at 50 percent speed needs to deliver only 12.5 percent of the horsepower required to run it at 100 percent speed. The reduction of horsepower means that it costs less to run that motor. When these savings are applied over the yearly y hours of operation, a significant savings can accumulate. 16
Affinity Table Numeric Description of the Affinity Laws Speed Flow Required Power 100% 100% 100% 90% 90% 73% 80% 80% 50% 70% 70% 34% 60% 60% 22% 50% 50% 13% 40% 40% 6% 30% 30% 3% 17
Payback on Variable Torque Applications. VFD Variable Torque drive takes advantage of the affinity laws on variable torque loads such as fans and pumps and does so without altering the voltage or interrupting power to the motor. Even with the motor running continuously, the current and KW required by the motor changes according to the actual load, i.e.: -loading and unloading of the motor by varying the speed of the load via magnetic coupling between the motor and the load. What you always pay for is the amount of KW used and even with the motor running continuously, the difference in the amount of kw required of any 3 phase motor from no load to full load is very significant. ifi 18
Example of an Excellent Variable Speed Drive Candidate* 19
Example of a Decent Variable Speed Drive Candidate* 20
Useful Information: VT Inverters & Motors-Variable Torque Hertz-Voltage = Speed of Motor Example: 10 HP-1800 RPM Inverter Motor, VT Turn Down Ratio On Drive, using Variable Torque of Blower Fan Example: 10 HP-1800 RPM 29.17 lb-ft =60 Hertz -100% Flow at 100% Speed 73HP 7.3 HP-1620 RPM 21.2929 lb-ft =54 Hertz - 90% Flow at 90% Speed 1.3 HP- 900 RPM 7.58 lb-ft =30 Hertz - 50% Flow at 50% Speed.3 HP- 600 RPM 2.62 lb-ft =20 Hertz - 30% Flow at 30% Speed Torque (in lb-ft) = HP X 5252 Example.3 X 5252 = 2.62 lb-ft Speed d( (In RPM) 600 Major Energy Saving on Variable Torque Motor Drive Applications from the Infinity Laws on Pumps & Fans. 21
Variable Torque (VT) Graph 22
Electric Motor Energy Facts Simple Payback Formula (.746 X Hp /Mtr. Eff.) X Hours X Days X KW Cost. Electric motors account for more than two-thirds of all energy used in the industrial market place. 63% of all energy consumed is linked to air & liquid flow in a pump or fan application Variable Torque applications. A typical 100 HP industrial motor, with an Nominal Prem. Efficiency value of 95.4 percent costs over $22,770 to operate continuously over a year. Based on 16 Hrs. Per day/260 Days Per Year at.07 KW. in this application, you can buy a new VFD drive below with energy savings. Example 10% Reduction in Speed on V/T VFD, using same scenario of costs, is a energy savings of 27% or $6,147 The average cost of the new VFD drive you are going buy is only going to cost $5,500 plus install and it s free money, purchased with energy savings, and your the hero. 23
Energy Savings Comparison Potential energy savings using a VFD vs. modulating flow with a damper In nput Pow wer (%) 140 130 120 110 100 90 80 70 60 50 40 30 20 10 Speed Reduction 10% = 35% Power Reduction Speed Reduction 20% = 45% Power Reduction Speed Reduction 30% = 65% Power Reduction Energy Saving Potential 10 20 30 40 50 60 70 80 90 100 Damper VFD VT Ideal Fan Control Flow Rate (%) 24
Useful Information: CT Inverters & Motors-Constant Torque Example: Hertz-Voltage = Speed of Motor Example: 10 HP-1800 RPM Inverter Motor 10-1, Turn Down Ratio On Drive, using Constant Torque on Conveyor Example: 10 HP-1800 RPM 29.17 lb-ft =60 Hertz-460 Volt, 7.66 V/Hertz Ratio 100% Speed 7.5HP-1200 RPM 29.17 lb-ft =45 Hertz-345 Volt, 7.66 V/Hertz Ratio 75% Speed 5.0HP- 900 RPM 29.17 lb-ft =30 Hertz-230 Volt, 7.66 V/Hertz Ratio 50% Speed 2.5HP- 450 RPM 29.17 lb-ft =15 Hertz-115 Volt, 7.66 V/Hertz Ratio 25% Speed 1.0HP- 180 RPM 29.17 lb-ft = 6 Hertz- 46 Volt, 7.66 V/Hertz Ratio 10% Speed Constant Torque= Constant Volts per Hertz ratio Example: 460 V = 7.66 V 230 V = 7.66 V 60 Hertz 30 Hertz Torque (in lb-ft) = HP X 5252 Example 10HP X 5252 = 29.17 Speed (In RPM) 1800 RPM Torque (in lb-ft) = HP X 5252 Example 5HP X 5252 = 29.17 Speed (In RPM) 900 RPM CONSTANT TORQUE IS THE SAME WORK( TORQUE ) AVAILABLE AT MOTOR SHAFT AT ALL SPEEDS! 25
Constant Torque Graph (CT) 26
Keyword is Proper Application of Equipment: Application of Poor Brakes or Just Poor Application. 2001 Corvette Applied or Misapplied as a Bumper Support Assist Device 27
How to select a Motor/Drive 10 Easy Steps What Power do you need (HP/KW) What Voltage (V) & Phase What type of Application (Constant or Variable Torque) What is the temperature/location where the drive is to be mounted What is the distance from the motor to the drive Are there Power Issues, do they have Drives installed now Is Braking required Is there Communications or Automation required What Construction-Enclosure and Eff. of Motor and Speed Range (Turndown) is required for application. What is Manufactures preference of customer and why 28
Thank You for Your Time and Hospitality and Courtesy QUESTIONS PLEASE: Handout: Covers Major Slides in Today's Presentation. I recommend you download: NEMA Application Guide For Adjustable Speed Drives Systems 2007 If I can be of further help, I can be reached at the following e-mail address or phone, which is: sholdridge @shermco.com & 972-793-5523 29