SCEM-P: Motor Driven Systems

In industrial plants and facilities, electric motors and motor driven systems are a part of everyday life. Engineers with job functional responsibilities for energy and facility management need a good understanding of how motor driven systems work. By gaining a good basic understanding of these integrated systems, engineers will be able to appreciate their potential and limitations.

Objectives

Topic 1: Concept of Power and Energy

• Calculation of energy savings
• Power factor correction
• Implementation at component or device level
• Implementation at system level
• Economic benefits
• Technical advantage/disadvantage comparison

Topic 2: Motors

• Operation and characteristics of electric motors
• Conventional DC Motors - shunt, series and compound
• AC Induction Motors – cage and wound rotor types
• Conventional synchronous motor
• PM synchronous motor
• Brushless DC Motor (BLDC, self synchronous motor)
• Motor efficiency
• Various losses in motors: copper , iron, core, stray, windage, hysteresis, eddy current losses
• Motor loading and efficiency
• High efficiency motors
• Speed control methods
• Variable applied voltage
• Variable armature current
• Variable motor field
• Variable frequency
• Combination of the above
• Selection and sizing of motors (including industry standards)

Topic 3: Drive Systems

• Power Electronic Converter and Inverter Switching Devices
• Main Components of VSD
• Types of VSD
• Voltage Source Inverter
• Current source inverter,
• PWM
• Key features of VSD
• Rectification
• Inverting
• Harmonic filtering
• Power factor correction
• Voltage level regulation / adjustment
• Energy reversal
• Selection, sizing and efficiency of VSD for variable torque load / constant torque load
• Application of converters for AC/ DC motor speed/torque control
• Application of converters for Permanent Magnet Synchronous (PMSM) speed/torque control

Topic 4: Driven Systems

• Types of transmission (belts, gears, coupling, chain, etc)
• Comparative features of transmission system
• Selection, Sizing and Efficiency of transmission system
• Typical Driven Systems- Pumps, Fans, Compressor, Hoist, Conveyor, etc
• Parallel and series pumping
• Losses in pumps, pump efficiency
• Fan losses and fan efficiency
• Affinity Laws – use affinity law to determine the min % of reduction in speed for a given % of reduction in quantity of delivery,
• Flow of regenerative energy
• Energy saving opportunities by applying variable speed to motors driving centrifugal pumps and fans and application of affinity laws
• Sizing of motors for variable torque load such as for centrifugal pumps, fans and compressors as well as for constant torque load
• Energy saving opportunities for linear load
• Geared/gearless elevator systems and escalators
• Counterbalance
• Case studies