Variable Frequency Drives are being installed more frequently today; however there are still several installations with VFD Issues being ignored or incorrectly being addressed. Examples of improper installations will be discussed to indicate potential problems that cause damaging consequences.
This presentation will provide an overview on the Distribution System from the Point of Common Coupling (Incoming Utility Power Connection Point) right down to the connection location of the motor(s). The student will be made aware of all the installation guidelines needed to ensure a successful installation of VFDs and associated Motors.
All issues related to Variable Frequency Drives and Motor installations will be presented with recommended solutions. We will work our way through a typical distribution system and discuss related issues or concerns at various points in the system. The course will be broken into the following six segments:
Our Variable Frequency Drive Basics course instructor looks forward to discussing any questions or issues that the participant may have related to their Motor and VFD applications. The course will be completed with a thorough specification guideline specifying the solution for proper VFD and Motor installations.
This course is ideally suited for the individuals that specify, design, purchase, install or use variable speed drive systems. This presentation will be a good overview without a lot of theory. Each participant will receive a DVD with dozens of articles and papers on VFD and Motor Data as well as the full coloured slide presentation for printing as required.
Each Variable Frequency Drive Basics course Training student will receive a detailed VFD specification and Check list to use to ensure that all their VFD issues are addressed.
The student will also receive an electronic copy of the Basics of AC Drives and the Basics of AC Motors. These two books are more than 1,000 pages, providing valuable information for the student for future reference.
VFD TRAINING COURSE BENEFITS
Paul Wright, P.Eng, Motors and Drives Consultant, The Electricity Forum
1. Typical Distribution System Overview
This seminar will discuss the Distribution components that make up a typical system and how they relate and impact the VFD and Motor selection.
Benefits of Using Variable Frequency Drives: The many benefits of using Variable Speed Drives will be discussed for several different applications such as fans, pumps conveyors and process machines. Several common reasons for using VFDs from Energy Savings, Unlimited Starting and Reversing, Precise Process control, Extension of Equipment Life will be reviewed. Significant capital and operating costs reduction possibilities will be shown.
2. Understanding AC Motors
This presentation will provide discussion on motor theory as applied to fixed speed and variable speed operation. The presentation will discuss the different motors’ performance and features available to the user: This presentation will start at the generation of a magnetic field and how to control this field to provide useful work. The following characteristics will be individually discussed to show their impact on the overall performance of the motor. Some of these characteristics will differ with changes in line voltages, line frequencies or both.
3. Understanding VFDs
This presentation will discuss the topology of todays’ low voltage VFDs. The function of the Rectifier, Pre Charge Circuit, DC Bus Capacitors, Chopper Circuit and Inverter section will be discussed. Discuss when to select PWM Control (V/Hz) or Vector Control operating modes. Discuss the selection of the voltage and current ratings of the VFD and the individual components that make up the complete system to show how the reliability of the VFD is improved.
This presentation will also provide a short digital tour a motor plant to show the different manufacturing steps to the assembly of an Above NEMA Squirrel cage Motor.
Daily Summary and Seminar wrap up
4. Motor Performance
The operation performance of AC Motors on fixed speed starters, reduced voltage solid state starters and on VFDs will be reviewed. This presentation will outline the significant differences in overall performance that the motor produces while starting, stopping, braking and reversing direction for the different control methods. Several new torque and current speed motor curves will be presented to highlight changes and their effect into the distribution system. Discussion of welding of contacts in motor starters and fuse failure or Circuit Breaker tripping when starting high inrush motors.
The torque and current versus speed curve characteristics will be discussed.
5. NEMA Motor specification Part 30 and Part 31 differences
This presentation will discuss the differences between the Standard for Part 30 designed Motors and the Standard for Part 31 designed Motors.
We will also review the motor technical ratings for typical NEMA motors built to NEMA Part 30 and 31 designs including: HP, RPM, FL RPM, NL AMPS, FL EFF., FL TORQUE and the equivalent circuit impedances. Understanding how the Voltage and Frequency affect Motor Performance: We will show the relationship of changing of the voltage and frequency will impact the development of torque and the speed of the motor. We will also discuss the differences in the Torque/Current versus Speed curve for motor on a fixed speed application versus that for a VFD operation.
Temperature, Service Factor & Insulation Class: The above electrical design criteria is necessary to ensure the motor can provide a suitable operating life in a given application. Each of the above criteria can have significant detrimental impact on the motors’ life. An increase of 10 degree Celsius temperature rise in the motor will cause a 50% reduction in the motors’ insulation life.
6. Understanding VFDs
This presentation will discuss the topology of todays’ low voltage VFDs used with PWM or Vector Control schemes. The function of the Rectifier, Pre Charge Circuit, DC Bus Capacitors, Chopper Circuit and Inverter section will be discussed. Discuss when to select PWM Control (V/Hz) or Vector Control operating modes. Discuss the selection of the voltage and current ratings of the VFD and the individual components that make up the complete system to show how the reliability of the VFD is improved. The student will learn how to select the VFD models from various Manufacturers that will be more reliable and have longer Mean Time Between Failures (MTBF).
7. Power Quality and Up Stream Issues
This presentation will look at the line side issues that a VFD may have on the power system. All the following issues will be discussed along with the recommended solution(s) for each issue:
8. Motor and Cable Down-Stream Issues
This presentation will look at the load side issues that a VFD may have in the motor circuit. All the following issues will be discussed along with the recommended solution(s) for each issue:
The effect of current flowing through the bearings and bearing housing will cause the inner and outer raceways to pit. Over time the pitting will continue to increase the depth of the groves and the bearing will eventually be damaged. The causes and remedies for bearing current issues will be discussed.
Why shielded VFD cables are recommended by the VFD manufacturers.
Radio Frequency and Electro Magnetic interference:
How they are produced and steps to mitigate the transmission of these unwanted noise signals. These high frequencies exhibit special characteristics that may cause undesirable effects in the industrial distribution and communication systems.
VFD and Motor Selection Examples:
This part of the presentation will look at a few applications where the operating performance characteristics for continuous and intermittent speed and torque ranges are provided. The student will be able to select the best combination of motor and VFD based on meeting or exceeding the specified criteria. The student will see the cost impact of their selection for the Motor and VFD to the cost of other possible acceptable selections.
Programming and Testing:
The most common 50-70 VFD setting parameters will presented. We will provide a parameter list for several different VFD manufacturers. The testing of the VFD packaged system is a very important procedure that makes the whole System complete. This verifies the controls and power wiring function as specified. A good testing program enables the VFD to be installed and commissioned on site without any issues. The proposed testing and commissioning procedures will be discussed.
Review of VFD Specification:
A generic non manufacturer biased VFD specification is provided to specify the minimum systems components to provide a for a reliable VFD package.
Daily Summary and Seminar wrap up
All students attending this presentation will receive electronic copy of the 9 Presentations plus several papers and booklets discussing the course and related material. A detailed VFD specification and Data Sheets will also be included to ensure future drive purchases provide reliable trouble free installations.
SPECIAL NOTE: Along with the above seminar material:
Each student will receive a detailed VFD specification and Check list to use to ensure that all the above issues are addressed.
The student will also receive an electronic copy of the Basics of AC Drives and the Basics of AC Motors. These two books are more than 100 pages, providing valuable information for the student for future reference.
Start: 8:00 a.m.
Coffee Break: 10:00 a.m.
Lunch: 12:00 noon
Restart: 1:15 p.m.
Finish: 4:30 p.m.