Application Guide

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INTRODUCTION
VFD Types
The following list gives mechanical, electrical and hydraulic VFD examples (many have a considerable mechanical content
needing regular maintenance):
1. Mechanical Drives.
a. Adjustable sheave belt drive.
b. Clutch.
c. Traction drive.
2. Electrical Drives.
a. Eddy—current clutch.
b. DC (rotating and solid state).
c. Solid state Vac.
d. Multi-speed motors.
3. Fluid drives.
Many of these can be replaced with a standard induction motor and a general purpose PWM VFD to provide a more reliable
and cost effective solution to the VFD requirement. Using a VFD often provides energy conservation benefits and
improvements in the accuracy of control as a bonus. Many opportunities for obtaining substantial savings are missed even
though advice is available from numerous sources, including Government, professional bodies, consultants and equipment
suppliers. The reasons for this include:
— Lack of awareness and/or skepticism regarding latest technologies.
— Overall financial and operational benefits are often not fully appreciated.
— Energy saving projects too often take second place to other production related expenditure.
— Lowest
first cost
takes precedence over
life cycle
cost (that is, initial cost plus running and maintenance costs).
Why Buy a VFD
Mechanical, electrical, and fluid power adjustable speed drives are available that offer some of the aforementioned benefits.
None combine all of the advantages of a VFD:
1. Variable speed and flow capability with standard induction motor.
a. Improved process control.
b. Energy savings.
2. Reduced voltage starting characteristics.
a. Soft start/smooth acceleration.
b. Reduces power supply problems in the facility.
c. Reduces motor heating and stress.
3. Used with standard AC induction motor.
Where are VFD Applications
Industry segments are important, because many applications are industry specific. Some
classic
VFD applications for various
industries are provided below:
1. HVAC, fans and pumps.
2. Food Processing: agitators, mixers, conveyors for food transport, packaging and bottling, preparation machines (slicers,
dicers, choppers), extruders, fans and pumps.
3. Petrochemicals: deep well pumps, oil field recovery, local distribution pumps, fans and pumps.
4. Mining and Metals: reheat furnaces, cooling beds, run in/out tables, fans and pumps.
5. Pulp and Paper/Forest Producers: washers, kilns, slitters, deckers, chippers, saws, sanders, peelers, de-barkers, fans
and pumps, vacuum removal systems.
6. Machine Tool: replace spindle drives, grinders, saws, lathes, tool positioning drives, balancing machines, fans and
pumps.
7. Transportation: material handling conveyors, cranes and hoists, small vehicle drives, fans and pumps.
8. Any machine or process that can be improved by varying speed or flow is a candidate for a VFD.