INTRODUCTION
Variable Frequency Drives (VFDs) are mechanical forms of variable speed drives, also known as adjustable speed drives. A VFD allows motor-based systems to adjust the speed at which the motor runs. That speed is based on how much power the mechanical systems need to meet the demand of the building. The demand of the system is also referred to as the “load” of the system. By varying the speed the motor is able to meet the needs of the load without using more energy than necessary.
Nearly all Variable Frequency Drives work on the basis of taking the existing AC supply, converting it to DC using a rectifier, and then converting it back to a variable frequency supply using an inverter. The inverter is the key part of this, so a variable frequency drive is sometimes simply called an inverter.
Currently, VFDs are being built into many new systems; however, they can also be added to some current systems through a retrofit. When looking to retrofit a system with a drive, consult a professional to match the drive with the existing system and motor. Making sure they are properly matched is very important in making sure you gain the highest efficiency possible.
WHO SHOULD ATTEND?
The technicians and maintenance staff will be able to perform correct maintenance procedures and troubleshooting of AC motors and VFDs. The Variable Frequency Drive training course is suitable to a wide range of professionals but will greatly benefit:
- Electrical engineers
- Maintenance technicians
- Management professionals
- Project engineers
PROGRAMME OBJECTIVES
- Understand the factors controlling speed of an induction motor
- Explain the construction and operation principles of VFD
- Determine the benefits of the VFD
- Understand the VFD technologies
- Explain the importance VFD maintenance
TRAINING METHODOLOGY
The goals of each participant are discussed to ensure their needs are fulfilled, as far as possible. Questions are encouraged throughout, particularly at the daily wrap up sessions. This provides opportunities for participants to discuss specific issues and, if possible, find appropriate solutions. Case studies are employed to highlight particular points and appropriate video materials used to illustrate particular conditions.
PROGRAMME SUMMARY
On completion of this EuroMaTech training course participants will be able to perform maintenance and troubleshooting of AC motors, VFD and soft starters. This will enable them to understand the operation of the components in the VFD and benefits
PROGRAM OUTLINE
Day 1: - FUNDAMENTALS OF THREE PHASE AC MOTORS, STARTERS AND FACTORS CONTROLLING SPEED
- Three-phase AC motors, types, construction, characteristics and applications
- Starting of induction motors and associated techniques and acceleration
- Speed control requirements of AC motors and load matching
- Soft starters characteristics
- Selection of AC motors for industrial applications and service factor
- Medium voltage motors and applications
Day 2: - CONSTRUCTION AND OPERATIONS OF VARIABLE FREQUENCY DRIVES
- Fundamental principles and understanding of VFDs
- Power semiconductors, diode, thyristor (SCR), IGBT, MOSFET, GTO and others.
- Voltage-source, current-source and pulse width modulated (PWM) inverters
- Benefits and applications of VFD
- Two-level PWM, regeneration and dynamic braking
- Medium voltage VFD
Day 3: - CHARACTERISTICS AND FUNCTIONALITIES OF PULSE WIDTH MODULATION
- The rectification process
- The DC bus process and functionalities
- The inverter types, process and functionalities
- Volts per hertz operation
- The Megadrive -Load commutated inverters
- PWM technology in Megadrive-LCI
Day 4: - TROUBLESHOOTING AND MAINTENANCE OF DRIVES
- Soft starters and selecting the correct VFD
- VFD analysers for converter failures, inverters and rectifiers
- Troubleshooting techniques and maintenance for VFD
- VFD parameter guidelines
- VFD parameter settings and settings
- VSD bearing failures and remedies
Day 5: - MAINTENANCE AND TESTING INSTRUMENTS FOR VFD
- Importance of maintenance
- Testing instruments and scopemeters for VFD
- Shaft ground rings
- Protection of inverters and electronic converters driving motors
- Case studies, selection and design
- Q&A and wrap up session
