The document provides information on AC drives from CG Drives, including their advantages, basic principles of operation, operating modes, braking types, and models. It discusses constant torque and variable torque loads, open loop V/F and vector control modes, closed loop vector control using feedback, and dynamic, DC injection, and regenerative braking methods. It also introduces the CG Drive-SK and CG Drive-SG product lines, specifying their features, connections, dimensions, and optional additions.

1. CG Drives

2. General Theory

3. Advantages of AC Drive
 Precise Control & Regulation of motor speed / torque
 Energy saving particularly for Fans & pumps
 Effective non-destructive braking
 Longer motor life
 Prevention of high in-rush starting current in motor
 Protections

4. What is a Drive ?
 Its is an electronic device which will control accurately
the output of an electric motor in response to a
controlling input.
 An AC Drive generates a variable voltage/frequency
output from a fixed frequency supply
 Have inbuilt protection in case of failure of itself or the
motor it controls
 To protect against motor overload, the Drive will limit the
continuous current into the motor, but provide additional
overload current for a finite time

5. What is a Drive ?
 The motor output will be totally variable within the
performance of the drive and motor.
 Drives can be called:-
• Inverters,
• VSD’s (Variable Speed Drives)
• VFD’s (Variable Frequency Drives)
• ASD’s (Adjustable Speed Drives)
• AFD’s (Adjustable Frequency Drives)
• Motor controllers
 Although these products have different names, the
hardware used is very similar (Input stage / DC Link /
Output stage), only the Drives internal software
(fimware) algorithm is different.

6. AC Drive Working Principle
N = (120 X f ) / P
T µ F X I
F µ V / f
P = (T X N) / 9550

7. Basic Principles of
Modes of operations
Frequency
Voltage
415V
fb
Constant Torque
Constant Power
(Field Weakening )
Torque
Torque
Boost

8. Types of Load

9. Types of Load
Frequency
Voltage
415V
fb
Constant Torque
Constant Power
(Field Weakening )
Torque
Torque
Boost

10. Types of Load
• Constant Torque load
– These loads can be conveyors, lifts or hoisting
applications
– Torque demand is constant
– Power demand is proportional to speed
– Load can be ‘Stiffer’ on starting (Stiction Torque) &
require greater starting torque than shown in the
diagram (conveyors).
Speed (w )
Torque
Power

11. Types of Load
Variable Torque load
– These loads are usually centrifugal fans
and pumps.
– Torque demand is proportional to the
square of the speed.
– Power demand is proportional to the
cube of the speed.
– Inverters used are usually in open loop
control due to small
torque requirement as speed low.
Torque (M) = k.w2
Power (P) = k.w3
Power
Torque
Speed ( w )

12. Types of Load
• Constant Horse Power Load
– These loads can be Winder & reelers, Wire-drawers & Web-feed printing
machines & Machine tool applications.
– Torque demand is proportional to the inverse of speed.
– Power demand is constant.
– Load largest at or close to zero speed,
requires that the drive has Very good starting
torque and linear Speed/Torque
characteristics (DC drives have been the main
control method for this type of application).
Torque
Speed (w )
Power

13. Application Load Breakaway Application Load Breakaway
Torque Torque
Agitators Machines
Liquid VT Moderates Boring CT Moderates
Slurry VT Moderates Botting CT Moderates
Blowers Milling CHP Moderates
Centrifugal VT Low Mills
positive displacement CT Low Rolling CT Moderates
Calenders CT Low Rubbers CT Moderates
Card machines CT Moderates Mixers
Centrifuges CT Moderates Chemical CT High
chippers CT Dough CT High
Compressors Slurry CT High
Axial centrifugal VT Low Plows- conveyor CT Moderates
Reciprocating CT Moderates Presses
Rotary CT Moderates Printing CT Moderates
Conveyors Punch CT Moderates
Belt CT Moderates Pullers-car CT Moderates
SCREW CT High Pumps
Shaker CT Moderates Centrifugal VT Low
Cranes Positive displacement CT Moderates
Bridge CT Moderates Slurry CT High
Trolly CT Moderates Roll Benders CT Moderates
Hoist CT Moderates Sanders CT Low
Crushers CT High Saws CT Moderates
Drill Presses CHP Moderates Shears CT Low
Elevators CT Moderates Tension Drives CHP Moderates
Extruders CT Moderates Tool Machines CHP Moderates
Fans- centrifugal VT Low Trademills CT Low
Frames - spinning CHP Low Winders CHP Moderates
Grinders CHP Moderates
Kilns CT High
Looms CT Moderates
Lathes CHP Moderates
VT= Varable Torque
CT= Constat Torque
CHP= Constant Horse Power
High = Greater than 150% Torque
Moderate = Between and including 100% to 150% torque
Low = Less than 100% Torque

14. • AC Inverter drive Block Diagram
3 Phase
Supply M
Input
Bridge
DC
Bus
Output
Bridge
The incoming 3ph
supply (fixed
frequency 220v/415v)
is rectified to a DC
voltage by the diode
bridge arrangement
The DC Link smooths the
rectified voltage, decouples
the input& output stages and
provides an energy
reservoir.
The Output stage(inverter
Stage) converts the DC Link
voltage to a variable
frequency AC supply which
generates the AC current in
the Motor

15. » AC Inverter power circuit
M
3ph Input supply Output Voltage
U
V
W
Motor current
220v/415v 3ph
voltage supply
(50~60Hz)
Input Bridge DC Link Output Stage
Diode Bridge DC Link IGBT Output Stage
The DC Link Inductance (used on units >4kW only)
smooths the rectified DC voltage, limits inrush current and
limits fault current
Inrush circuit. Resistor limits initial current flow (DC Link
capacitors S/C at power-up), Relay bypasses resistor during
normal operation.
IGBT (Insulated Gate Bipolar Transistor). A switch used
in groups to convert the DC voltage to a variable frequency
output voltage (controlled via microprocessor using PWM
methodology)
600~800vDC
0~220 / 415v
variable F
output

16. Inverter Theory
• Pulse Width Modulation (PWM)

17. AC Drive
Operating modes

18. Operating modes
Drive Operating modes
 Open Loop Mode
• Fixed Boost Mode (Constant V/F mode)
• Quadratic V/F
 Open Loop Vector Mode
 Closed Loop vector Mode

19. V/F Mode

20. Operating modes
Open Loop mode
 For use with standard AC induction motors without a feedback
device.
 The drive applies power to the motor at frequencies varied by
the user.
 The motor speed is a result of the output frequency of the
drive and slip due to mechanical load.
 The drive can improve the speed control of the motor by
applying slip compensation.
 The performance at low speed depends on whether V/F mode
or open loop vector mode is selected.
 Can control Squirrel cage, Wound rotor and Linear Induction
motors

21. Operating modes
Open Loop - Constant V/F
 A versatile control mode for single or multi -motor control
 The voltage applied to the machine is proportional to the frequency
 At low frequencies a fixed boost is added to compensate for the voltage drop due to
the machines resistance (Boost voltage 0 ~25% of maximum motor voltage).
 The drive output frequency is defined by the selected frequency reference (up to a
maximum of 1500Hz).
 The drive includes slip compensation so that speed can be held constant with
varying load
 Can be used with other types of motors or variable frequency supply applications
 If the machine load current exceeds the drive limit, the frequency is modified to
reduce the load.

22. Operating modes
Open Loop - Constant V/F
100% Rated F
2
Output voltage
100% Motor
Rated Voltage
Motor Rated Voltage
2
Boost Voltage (%)
Output frequency
100% Motor Rated F

23. Operating modes
Open Loop – Quadratic V/F
 A control mode for single motors operating fans or pumps with
Quadratic load characteristics
 The voltage applied to the motor is directly proportional to the
square of the frequency applied to the motor.
 At low frequencies a fixed boost is added to compensate for the voltage
drop due to the machines resistance (Boost voltage 0 ~25% of maximum
motor voltage).
 The drive output frequency is defined by the selected frequency reference
(up to a maximum of 1500Hz).
 The drive includes slip compensation so that speed can be held constant
with varying load
 This operating mode is not suitable if a high starting torque is required.

24. Operating modes
Open Loop – Quadratic V/F
100% Motor
Rated Voltage (V)
Boost Voltage (%)
Output frequency
100% Motor Rated F (Hz)

25. Speed Torque characteristic V F AC Drive

26. Open Loop Vector mode

27. Operating modes
Open Loop Vector mode
 This is the default operating mode in Open loop
 The voltage applied to the machine is proportional to the frequency
 At low frequencies (below half motor rated frequency), stator resistance compensation is
applied to give optimum starting torque, the information for this is provided via an auto-tune of
the motor characteristics.
 An auto-tune function can be carried via the drive to calculate the stator resistance and
voltage offset value for the motor equivalent circuit.
 An Autotune can also be carried out to accurately calculate the motor power factor.
 Typically, 100% load Torque is available down 1Hz from a 50Hz motor.
 Differing modes of operation compensate for resistance changes due to temperature changes.

28. Operating modes
Open Loop Vector mode
 This is the default operating mode in Open loop
 The Information provided is used to control the motor flux to
provide optimum Torque.
 Slip compensation can also be applied via parameter settings in the
Drive.

29. Operating modes
Open Loop Vector mode
Motor
Power
Base Speed
1-2 Hz Motor Torque

30. Speed Torque Characteristic Open loop vector AC Drive

31. Closed Loop Vector mode

32. Operating modes
Closed Loop Vector mode
 This control mode is for AC induction motors with a feedback device.
 The drive controls the speed of the motor using the feedback device to ensure the
rotor speed is exactly as demanded.
 Motor flux is controlled to ensure that 100% Torque is available down too zero
speed.
 Speed/position feedback is used to convert the current feedback into a Magnetising
current (to control motor flux) and an Active component to control Motor Torque.
 The level of the torque producing current is defined by the speed controller using
the speed/position feedback to determine the actual motor speed.
 The Speed Loop and Current loop of the Drive have variable gain values to allow
for different load characteristics.

33. Operating modes
Closed Loop Vector mode
 This control mode is for AC induction motors with a feedback device.
 Inertia measurement of the Combined motor/load inertia can be
carried out to aid setting of speed loop PID gains.
 Current Loop gain values are calculated when an autotune function
is carried out .

34. Operating modes
100%
Closed Loop Vector mode
Motor
Power
Motor Speed
Base Speed
Motor Torque

35. Operating modes
Closed Loop Vector mode
I Loop
gains
Speed error
Speed
Loop gains
IFb
Position Fb
Speed Loop Output /
Current reference
Current error
Speed reference
E

36. AC Drives Braking

37. Types of Braking
- Dynamic Braking
- D.C. Injection Braking
- Regenerative Braking

38. Braking Principal
When braking occurs, the Regenerative energy from the
motor is returned to the DC Link of the drive (through diodes
in the output Bridge),the DC Link voltage rises and if left
unchecked will damage the drive, unless Over voltage
protection circuitry is utilised
Regenerating power
Motoring
power
U
Load
L1
L2
L3
VW
This Regen energy must be
dissipated, this is done via a
resistor placed across the DC
Link of the drive or by using an
Active front end on the drive
capable of inverting the DC
voltage back into the AC supply

39. • Dynamic Braking
• D.C. Braking
Monitor
+
-
M
I F/B
In circuit overload
protection device External Braking
Resistor Energy of Load

40. CG Drives

41. Crompton Greaves…
CG Drives
Benefits of Choosing AC Drives from CG…..
• Single Point Reference for both ,Motor & AC Drive
• Package Performance guaranteed by CG.
• Perfect Selection of Motor and Drives ,together.
• CG’s Technical team extensively tests CG Motors and CG Drives,together.
• CG Understands applications and package solution can be tailored
according to the need of your application.
Just tell us your application……
.…..And CG offers you Packaged solution !
………..And Standalone Drives too!

42. CG Drive-SK

43. Over View of CG Drive-SK

44. CG Drive - SK…
• Range
– Single Phase : 0.25 kW upto 0.75 kW
– Dual Phase : 1.1 kW upto 2.2 kW
– Three Phase : 0.37 kW upto 45 kW
• Input Voltage Supply : 200V and 400V class
• Main Features
– Sensorless Vector Drive
– Very Compact,Simple to use and Flexible range
– Dynamic Braking Built-in for entire range
– PLC functionality built-in with lot of Input/Outputs
– Built-in EMC Filter
– Communication Port (RS 485) as standard
Approvals - UL, CUL, CE, ISO14001, ISO9001:2000

45. The Model code description for the CG Drive-SK
CGK 4 3 XXXXX
Drive kilowatt rating: 00025 = 0.25kW
Number of input phases: 1 = 1phase,
3 = 3phase, D = 1 and 3phase
Drive voltage rating: 2 = 230V, 4 =
400V
Model: CG DRIVE-SK

46. Model Number wise ratings for entire range

47. CG Drive – SK…
Dimensions (Upto 4kW)
0.95-1.0kG 1.2-1.4kG 2.1kG

48. CG Drive – SK…
Dimensions (7.5kW to 45kW)
7 kG 15 kG
30 kG

49. CG Drive – SK…
Typical Connections & I/Os
Dynamic braking
transistor
as standard in-built
Digital I/P-5,
Digital O/P-1,
Analog I/P-2,
Analog O/P-1,
Relay O/P-1

50. CG Drive - SG

51. CG Drive - SG…
• Range
– Capacity: 5.5 to 200 kW…….extended upto 400 kW
– Three Phase
• Input Supply Voltage : 200 V and 400 V class
• Main Features
–136 % / 150 % Overload Capacity
–Flexibility of using same drive for 200 V / 400 V class
–Two Analog Outputs
–Dynamic Braking Built-in upto 55 kW(>55 kW optional)
–Can accept Direct DC Input
–DC Bus Sharing (Electronic Shaft )

52. CG Drive - SG…
A Series of Intelligent Functions…
• Sensor less Vector Control
• Motor parameter self tuning
• Integrated Dynamic braking Up to 55kW(Optional > 55 kW)
• Highly configurable DC Braking
• Programmable Switching Frequency up to 16kHz
• Programmable & predefined V/f curves
• 4 independent programmable ramps (linear / S-Curve)
• Flying restart
• Mains loss detection with controlled stop
• Motor thermal protection
• PID Application block
• Programmable auto restart(No & duration between restart)
• Skip frequencies

53. The Model code description for the CG Drive-SG
CGG -
2 075 - K B X - 4
MAINS SUPPLY VOLTAGE
X = SOFTWARE STANDARD
B= INTEGRATED BRAKING
X= NOT INTEGRATED BRAKING
K= KEYPAD INCLUDED
DRIVE KW RATING
DRIVE MEHANICAL DIMENSION
DRIVE SERIES

54. CG Drive - SG…
I/Os
Equipped with a large
number of standard
I/Os…
• 3 Differential Analog I/Ps
• 8 Digital I/P
• 2 Analog O/Ps
• 4 Digital O/Ps

55. SG Drive – SG…
Dimensions & Mounting

56. CG Drive – SG…
A Comprehensive range of dedicated Options
Encoder feedback management
Digital Input Interface at 120VAC
Multilanguage Programming keypad
I/O Expansion
Data Storage Device
CANOpen/DeviceNet Interface
Profibus Interface

57. Selection of Inverter

58. Motor rated current
MACHINE NO. NADWN 30425 BT TOP FRAME NDW225S
KW(HP) 20(27) RPM 970 EFF(FL) 86 %
VOLT 415 A 37 DUTY S4 (60%)
IP 55 CONN. DIAG. 3MS HZ 50
REF FEAM3296 INS . CL. F AMB 45 C
GREASE MADE IN
INDIA
LITHIUM BASE 2 3 PHASE INDUCTION MOTOR REF . IS 329
Motor rated Voltage
(Pr08)
Rated full-load speed (Rpm)
(Pr07)
kW Output power
(Pr06)
Getting Started

59. Inputs to be taken from User…
while selecting the Inverter
 Types of load driven
 Load Requirements
1. Constant Torque
2. Variable Torque
3. Constant power
 Existing motor Name plate details
 Load speed Requirements .
 One,Two or Four Quadrants.
 Accuracy and response time.
 Control with speed sensor or sensorless control.
 Environmental consideration(Ambient temp,Humidity,Altitude)
 System interfacing requirement

60. Major Customers
Fans & Pumps
Applications

61. SL. No. Customer Rating QTY. Application Y.O.S
1 Durgapur Steel 160KW 3 Gas Booster Fan 2006
2 Veda Engg.
Pvt. Ltd. - Pune
75KW 6 CT Fan 2006
3 GMDC-Ahmedabad
200KW 1 ID Fan 2006
4 BILT-Chandrapur
250KW 2 Feed Pump 2007
5 BILT-Chandrapur
160KW 3 ID Fan 2007
6 BILT-Jaypure,
Orissa
90KW 2 Pump 2007
7 IFFCO-Paradip
Orissa
75KW,45K
W,37KW
2 each Pump 2007
6 BILT-Yamunanagar
250KW 1 ID Fan 2007
7 Trivista Steel &
Power Ltd.-
Karnataka
200KW 1 ID Fan 2008

62. Energy Saving CG Drives

63. SL. No. Application VFD
Rating
KW W/O
VFD
KW
With
VFD
KW
Saving
1 Fan 160KW 124KW 116KW 8KW
2 Blow Tank
Pumps
75KW 50KW 25KW 25KW
3 Pump 37KW 29KW 22KW 7KW
4 ID Fan 110KW 74KW 36KW 38KW
5 White Liquid
Supply Pumps
18.5KW 14KW 10.5KW 3.5KW
6 Ash Mixing
Pumps
37KW 32KW 20KW 12KW
Data provided by M/s BILT-Chandrapur

64. SL.
No.
Customer Rating QTY. Applicatio
n
Y.O.S
8 Wacker Metroarc
Chemicals Pvt. Ltd.
2.2KW to
90KW
>15 Pump 2006-09
9 Ruchira Paper Mills
Ltd.-Baddi(HP)
132KW,
45KW,37KW
1
each
ID/PA/SA
Fans
2008
10 Anvil Cables Ltd.-
Jamshedpur
110KW,45KW 1 Wire Drawing 2006
11 DSPL-Jajpur(Orissa) 75KW 2 DRI Kiln,
SAF
2009
12 Jindal India Ltd. 75KW 1 Fan 2009
14 Rupa & Company
Ltd.-Kolkata
45KW,37KW &
1.5KW
2
each
Boiler
Applications
2008
13 Presales Pvt. Ltd.
(OEM Boiler)-
Cuttack(Orissa)
0.75KW to
200KW
>30 Boiler
applications
2006-09