This document summarizes a presentation on variable frequency drives (VFDs). VFDs vary the speed of 3-phase AC motors by converting AC power to DC and then converting it back to variable voltage/frequency AC. They allow constant and variable torque motor loads to operate at variable speeds. Applications include pumps, fans, compressors. Selecting a VFD depends on the motor's current, kW rating, type of machine/application, and required functionality/controls. Rockwell Automation offers their PowerFlex line of VFDs in compact, standard, and premium models for applications from small to large horsepower. The presentation reviews VFD components, operations, applications in industries, and key selection factors.

1. Tomorrow’s Automation, Today
A Symposium on Virtualization For the Process &
Manufacturing Industries

2. TR03B Variable Frequency Drives
Omar Javed – Manager Sales Oct. 20, 2015 |
15:00 PM – 15:30 PM

3. Variable Frequency
Drives
Agenda
This session explains very brief overview
of Variable Frequency Drives; general
introduction followed by industrial
examples, applicable industries and
operations to be focused.
What is VFD?
What are the concerns?
Solutions

4. What is VFD
Electrical/electronic piece
of equipment that varies
the speed of a 3 phase AC
motor.
Also Called:
VSD [ Variable Speed Drive]
ASD [Adjustable Speed Drive]
AFD [Adjustable frequency drive]
4

5. Basic VFD Operations
Convert AC power to DC power.
Filter DC power.
Invert DC power to variable voltage and variable
frequency AC power
5

6. VFD Block Diagram

7. Motor Load Groups: Constant Torque Load
100
Horsepower
Demanded
by the Load %
Speed %
100
Torque
Demanded by
the Load %
Speed % 100 100
7

8. Constant Torque “CT” Applications
Positive Displacement Pumps
Reciprocating Compressors
Rotary Compressors
8

9. Variable Torque Load
Torque
Demanded
by the Load %
Speed % 100
100
Horsepower
Demanded
by the Load %
Speed %
100
100
9

10. Variable Torque “VT” Applications
Centrifugal Fans
Centrifugal Pumps
Centrifugal Blower
10

11. Affinity Law
𝐵𝐻𝑃1
𝐵𝐻𝑃2
=
𝑁1
𝑁2
3
BHP = Brake Horsepower
N = Speed
Example
N1 = 3,550 N2 = (3,550 x .9) = 3,195
BHP1 = 3.53
BHP2 = [3.53 x (3,195/3,550)3 ] = [3.53 x (.9 x .9 x .9)] = (3.53 x .729)
= 2.574
11

12. Speed Reduction by 10% Achieve
savings up to 30 %
12

13. Output or Cable Device
Termination
AC Drive
Input Filter**
Line Reactor
Input fusing & circuit
breakers
ACSupplySource
AC Motor
13

14. Normal Duty or
Heavy Duty
If a normal duty overload characteristic
is chosen, an oversize motor allows up
to 110% torque performance for up to 1
min. in both CT and VT.
This function is used mainly for pumps
and fans, since these applications do not
require an overload torque.
If a heavy duty overload characteristic is
chosen, a rated motor with the
frequency converter obtains up to 160%
torque for 1 min. in both CT and VT
14

15. What do You Need to
Know to Select a
Drive?
Current
rating (A)
of the
motor
kW rating
of the
motor
Type of
Machine
(Application)
IP Rating
• IP20 = Clean Switch
room, Switchboard
• IP54 = Dust/Damp
Wall Mount
• IP66 = Washdown
Functionality
• How is the drive
being controlled?
• I/O?
• Communications?.
Most
Important
Least
Important
15

16. What Rockwell Automation is Offering

17. PowerFlex Family of Low Voltage Drives
PowerFlex Drives meet worldwide standards out of-the-box, achieving EMC, global voltage and
safety requirements.
PowerFlex Compact Drives offer cost-effective motor control for machine-level and stand-
alone applications (PowerFlex 523, 525, 527, 40, 40P)
PowerFlex Standard Drives are designed for application flexibility and control system
integration (PowerFlex 400, 70, 700, 753)
PowerFlex Premium Drives are designed for advanced applications with tight control system
integration and extended Power Ranges (PowerFlex 700L, 700H, 700S, 755)
Power Flex MV Drives (7000 & 600) Designed for Medium Voltage Applications
17

18. Power
Performance
Compact
Standard
Premium
PowerFlex Family of Low Voltage Drives
18

19. PowerFlex
750 Series
AC Drives
PowerFlex 755
Premium Integration
AC Drive
PowerFlex 753
General Purpose
AC Drive
Panel Mount Drives
0.75 to 250 kW @ 400V
1.0 to 350 Hp @ 480 V
.5 to 300 Hp @ 600V
5.5 to 250 kW @ 690V
Panel Mount Drives
0.75 to 250 kW @ 400V
1.0 to 350 Hp @ 480V
.5 to 350 Hp @ 600V
5.5 to 250 kW @ 690V
Floor Mount AC Drives
315to1400kW@400V
400to2000Hp@480V
250to1500Hp@600V
200to1500kW@690V
PowerFlex 750-Series AC Drives
Ratingsto250kW/350Hp Ratings to 1500 kW / 2000 Hp
19

20. PowerFlex MV (7000, 6000)
Rockwell’s 3rd generation MV Drive
Incorporates leading-edge technology, embedded
communications, and significant commonality across multiple
platforms, networks, operator interface programming and
hardware.
Designed for end users, solution providers and OEMs
Air-cooled and Liquid-cooled drives
Applications ranging up tov9000 horsepower (6340 kW).
20

21. Value Delivered
Faster Time
to Market
$ $$
Lower Total Cost of
Ownership
Improved Asset
Utilization
Enterprise Risk
Management

22. Timeline Review

23. Original Hardwired
System
Typically configured using:
 Two different software tools
 Two different cables or
converters
 Sometimes by two different
people
23

24. Early
Networks
Same as hardwired system
 Typically configured
using two different
software tools
 Two different cables or
converters
 Sometimes by two
different people
24

25. Use of Dual
Networks
Typically configured using
two different software tools
25

26. Integrated
Software Today
Single Software Tool
 Configure network i/o
connection to the drive
One time, in One place &
by One person
 Eliminates potential for
user error when
configuring network i/o
26

27. Success Story
Lalpir Power Plant & Nestle
4

28. Question & Answers
Thank You for Your Valuable Time

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