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Friday, July 19, 2013

PowerPoint Presentation On VARIABLE SPEED DRIVES

PPT On VARIABLE SPEED DRIVES
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VARIABLE SPEED DRIVES Presentation Transcript:
1.VARIABLE SPEED DRIVES

2. WHAT IS VARIABLE SPEED DRIVES?
A variable speed drive (VSD), also known as a frequency converter, adjustable speed drive or inverter, is an electronic device that controls the characteristics of a motor’s electrical supply. Therefore, it is able to control the speed and torque of a motor, achieving a better match with the process requirements of the machine it is driving. So in applications where variable control is desirable, slowing down a motor with a VSD does reduce energy use substantially.

3.WHY VARIABLE SPEED DRIVES ?
Save energy and improve efficiency
Process controllability
Reduced mechanical wear and shock
Improved power factor
Coordination of motion on various shafts
Easy interfacing with automation systems

4.BENEFITS OF VARIABLE SPEED DRIVES
 In addition to energy savings and better process control, VFDs can provide other benefits:  A VFD may be used for control of process temperature, pressure or flow without use  of a separate controller. Suitable sensors and electronics are used to interface driven equipment with VFD. Maintenance costs can be lowered, since lower operating speeds result in longer life for bearings and motors. Eliminating throttling valves and dampers also does away with maintaining these devices and all associated controls. A soft starter for motor is no longer required. Controlled ramp-up speed in a liquid system can eliminate water hammer problems.  Ability of a VFD to limit torque to a user-selected level can protect driven equipment  that cannot tolerate excessive torque.

5.Type of Drives
Mechanical variable speed drives
Hydraulic variable speed drives
Electrical variable speed drives

6. Mechanical variable speed drives
Belt and chain drives with adjustable diameter sheaves Metallic friction dr
ives

7.Hydraulic variable speed drives
Hydrodynamic types

Hydrostatic types

8.Electrical variable speed drives
DC Motor Drives Eddy Current Motor Drives AC Motor Drives

9. The workhorse of industry is
           the “ELECTRIC MOTOR”
All of the machines mentioned earlier in the industries commonly driven by electric motors. It can be said that the electric motor is the workhorse of industrial processes. Now in this  we will take a closer look at electrical motors - especially the squirrel cage AC motor with ac drives(VFD) , which is the most common motor used in industrial processes.

10.CONTROL PRINCIPAL OF VARIABLE SPEED DRIVES
A VSD works by converting the incoming electrical supply of fixed frequency into a variable frequency output. This variation in frequency allows the drive to control the way in which the motor operates — a low frequency for a slow speed, and a higher frequency for a faster speed. The output can also be changed to enable the motor to generate more or less torque as required. So, the motor and drive combination might be used for turning a large load at fairly slow speeds, or turning a lighter load at high speeds, maximising efficiency.

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