This document provides information on drives, force, torque, inertia, speed, work, power, electrical power, DC circuits, AC circuits, AC motors, AC drives, and their operation and components. It discusses the basics of force, torque, inertia and their relationships. It also explains speed, work, power, horsepower, electrical power in DC and AC circuits. The document then covers the construction, nameplate, and operation of 3-phase AC motors. It concludes by describing the basics and components of AC drives including PWM technology, IGBTs, vector control and their parameters and commissioning.

1. DRIVES
BASICS

2. FORCE
•FORCE is a PUSH or PULL.
•FORCE is caused by Electromagnetism,
gravity or a combination of physical means.
•Net force is a vector sum of all force.

3. TORQUE
•TORQUE = Force x Radius
•TORQUE is the product of Force & Radius, its
measured in lb-feet

4. INERTIA
• The law of Inertia states that an object will
tend to remain in its current state of rest or
motion unless acted upon by an external force.
• example:
A soccer ball remains at rest until a player
applies a force by kicking it or the ball will remain in
motion until another force, such as friction or goal
net, stops it.

5. SPEED
• An Object in motion travels a distance in a
given time.
• Speed is the ratio of the distance traveled
and the time it takes to travel the distance.
Speed= Distance
time
• Speed of Rotating Object: Speed of rotating
object is generally given in Revolution Per Minute.
eg. Motor Speed, Speed of Car Wheel etc.
• Acceleration & Deceleration: Change in Speed
from lower to higher is called Acceleration & from
higher to lower is called Deceleration.

6. WORK & POWER
• WORK: Whenever a force of any kind cause
motion, work is accomplished. Work is generally
expressed in foot-pounds and is defined by the
product of the net force F & the distance d moved.
W = F*d
• POWER: Power is the rate of doing work.
POWER = FORCE * DISTANCE
TIME
= WORK
TIME
• Horsepower: Power is expressed in Foot-pounds
per seconds, but normally is expressed in
Horsepower (HP). This unit is defined by James
Watts.
HP =T * RPM
5250

7. ELECTRICAL POWER
• In Electrical circuit, Voltage applied to
conductor will cause electron to flow. Voltage
is the force and electron flow is the motion.
The rate at which work is done is
called POWER and is represented
by the symbol “P”. Power is
measured in WATTS represented by
the symbol “W”.
Here Electron flow is the Motion &
Voltage is the force.

8. POWER IN DC CIRCUIT
Power consumed in a resistor depends on the
amount of current that passes through the resistor
for a given voltage.
Power= Voltage * Current
P= V * I
P= 12 V * 2 A
P= 24 W
example:

9. POWER IN AC CIRCUIT
Power in an AC circuit is the Vector sum of True
Power & Reactive Power.
Power= Voltage * Current * Cos Ø
Where Power Factor (CosØ) is the ratio of true power to
apparent power.
P = V*I*Cos Ø
For single phase:
P = √3*V*I*Cos Ø
For three phase:

10. Relation between HP & kW
• Equipment mfg in Europe is generally rated
in kW & mfg in US is rated in HP.
• HP can be converted into kW with:
kW = 0.746 * HP
HP = 1.341 * kW
• kW can be converted into HP with:

11. An AC Motor
A motor is a device which uses Electrical Energy to
produce Motion.
Motors may be parts of Fan or Pump or may be
connected to other equipment such as Conveyors,
Winders & Mixers etc…….
• Stator: Electromagnetic Stator windings are mounted in a
housing. Power connections are brought out to be attached to
a three-phase power supply.
• Rotor: A rotor which consist of a laminated, cylindrical iron
core with slots for receiving the conductors. The most common
type of rotor has cast-aluminum conductors and short-
circuiting end rings. Rotors are mounted on a shaft and
supported by bearings.
• On self cooled motors a Fan is mounted on the shaft to force
cooling air over the motor.

12. AC Motor and its name plate

13. AC Motor construction

14. AC Motor name plate

15. Operation of 3 Phase
Rotating Magnetic field
•An ac motor "squirrel cage" rotates when the moving
magnetic field induces a current in the shorted
conductors.
•The speed at which the ac motor magnetic field
rotates is the synchronous speed of the ac motor and
is determined by the number of poles in the stator and
the frequency of the power supply:
where ns = synchronous speed,
f = frequency, and
p = the number of poles.
ns = 120f/p

16. Torque
• Torque is directly proportional to Voltage & Current &
invert proportional to Frequency.
T = k Ø Iw T = Torque
F = Supply Frequency
Ø = Flux
Iw = Working Current
T  Ø Iw
T  V/F Iw
• Increasing in Frequency without increasing Voltage will
cause increasing in Speed & decreasing in motor torque
or decreasing in Frequency will cause decreasing in
Speed & increasing in Motor Torque.

17. Basics of AC Drives
• Siemens Midimaster, Micromaster Vector, Master Drives
are comes with PWM technology for more Sinusoidal
current output to control frequency and voltage
supplied to an AC motor.
• PWM drives are more
efficient and typically
provide higher level of
performance.
• A basic PWM drive
consist of a Converter,
DC link, Control logic
and an Inverter.

18. Basics of AC Drives
• The Converter section consist of a fixed diode bridge
rectifier which converts the 3-phaset power supply to a
DC Voltage.
• The L1 choke and C1 capacitors are used as a filter and
smooth the converted DC Voltage.
• The rectified DC Value
is approx. 1.35 times
the line-2-line value of
the supply voltage.

19. Basics of AC Drives
• Output voltage and frequency to the motor are
controlled by the control logic and inverter section.
• The inverter section
consist of six switching
devices.
• Various devices can be
used such as Thyristor,
bipolar transistor,
MOSFETs and IGBTs.
IGBTs

20. IGBT
• IGBTs = Insulated Gate Bipolar Transistor.
 Advantages:
o Provide a high switching speed for
PWM inverter operation.
o Are capable of switching ON & OFF
several thousands times a second.
o Can turn on in less than 400
nanoseconds.
o Can turn off in less than 500
nanoseconds.
o Low switching losses.
o High Input Impedance.

21. PWM Technology
• PWM = Pulse Width Modulation
• In this the positive & negative halves of quasi-square
output are chopped. By chopping we don’t get a
sinusoidal voltage at the output but we can make the
current to motor is sinusoidal.
600 v dc
Shorter ON duration, Lower Voltage
600 v dc
Longer ON duration, Higher Voltage
Output
Voltage
Output
Frequency

23. Power Configuration

24. S1
S1
RECTIFIER CIRCUIT
INVERTER CIRCUIT
C1
PRECHARGING
RESISTOR
3 PHASE
INPUT
3 PHASE
OUTPUT
C1= CAPACITOR
S1= MAIN CONTACTOR
Precharging Circuit
•To reduce the capacitive inrush current at starting,
Precharging resistors are used
• Size and rating of these resistors are4 depend upon KW
rating of the drive.
• S1 contacts are initialize when 80% of the dc link
voltage has built up.

25. RFG
Speed
Controller
Current
Controller
Gating
Unit
Speed
Setpoint M
T
Ramp
Function
Generator
Speed
Controller
• Speed Controller: Speed controller compares Speed Setpoint & Actual
Value, if this two quantities deviate, it applies corresponding current
setpoint to Current Controller.
The P gain of the speed controller can be adapted
as a function of actual speed, actual current, setpoint /actual value
deviation or winding diameter.
To achieve a better dynamic response in the speed
control loop, a feed-forward control function can be applied. For this
purpose, a torque setpoint quantity can be added after the speed controller
as a function of friction or drive moment of inertia.
Actual
Speed
Value
• Actual Speed Value: Analog Tachometer
Pulse Encoder
Drive Software – Speed Control

26. Current
Limitatio
n
• Current Limitation: The Purpose of the current limitation set after the
torque limit is to protect the CONVERTER & MOTOR.
• Features: Independent setting of Positive & Negative Current Limit.
Separate current limit setting for Shut down & Fast stop.
Free input current limit by means of connector eg. via AI or USS
Speed dependent current limit.
RFG
Speed
Controller
Current
Controller
Gating
Unit
Speed
Setpoint M
CT
Current
Controller
•Current Controller: Current Controller is a PI Controller with mutually
independent P Gain & reset time settings. It can be set pure P controller or I
controller.
•The Current controller output transfers the firing angle to the gating unit.
Gating
Unit
•The Gating unit generates gate pulses for the Power section thyristors in
synchronism with line voltage. The Gating pulses position timing is determined by
the output values of the current controllers.
Drive Software – Current Control

27. Parameters are the intervention points for adapting operating functions to an
application and settings of Motor data for which drive is being used.
The various parameters are differentiated according to their function as follows:
♦ Setting parameters (can be read and written)
♦ Visualization parameters (can only be read).
PARAMETERS
SPEED SETPOINTS
Analog Values (0-10V DC, 0-20mA, 4-20mA)
Integrated Motorized Potentiometer
Fixed Set points
Communications like RS-485, Profibus, Profinet, Modbus, CanBus.

28. Communication with PLC

29. Stopping Methods
• There are three ways to stop any motor with Siemens make drives.
1. OFF1- CONTROLLED STOP
2. OFF2- UNCONTROLLED STOP
3. OFF3- FORCED STOP
• OFF 1 – in this method, drive will stop in accordance with ramp down time of the
drive. So the ramp down time must be set accordingly to avoid dc link over voltage
fault.
• OFF 2 – in this method, Drive will disable the output pulses and immediately the
output goes to zero, so the motor will stop according to the moment of inertia.
• OFF 3 –This is controlled stop with E-stop. In this method, motor will stop in
accordance with OFF3 ramp down time of the drive. Generally, OFF 3 ramp down
time is less than the OFF 1 ramp down time.

30. Braking Methods
•DC Braking: DC current is impressed in the stator winding
which results in a significant braking torque for an
Induction motor.
The magnitude, duration and frequency at which braking
starts can be set for the braking current and braking torque
by parameters.
DC Braking specially used for
•Centrifuges,
•Saws,
•Grinding Machines,
•Conveyor belts etc…

31. Braking Methods
•DYNAMIC Braking: When the motor is in the regenerative
mode, the energy from the motor is fed back into the DC
link of the drive converter via the inverter. This means
that the DC link voltage increases and when the maximum
threshold is reached, the drive is shutdown with Over
Voltage fault. This shutdown can be avoided by using
Dynamic braking.

32. 3 Ph I/P
650 V DC
Braking Methods
•REGENRATIVE Braking: When the motor is in the
regenerative mode, the energy from the motor is fed back
into the DC link of the drive converter via the inverter &
these voltages are converted into AC voltage via
Regenerative unit & these voltages are connected to 3 ph
I/P via Autotransformer.

33. Line Chokes
Output Chokes
Braking Resistors
Filters

34. Open Loop V/f control (Linear)

35. Open Loop V/f control (Parabolic)

36. Operating type “Vector”, V/Hz Control
M
RFG
N set
V/Hz
voltage
frequency
U
Current Limit
Slip
Compensation
I * R
Compensation
Actual Current Value Sensing
I max
-I act IxR slip
-
+
f
-
+
+
+
+
+

37. Speed
Controller
N set
set
Field
Current
Controller
P
K
M
U set
Phi
Coordinate
Transformati
on
I uvw
Torque Current
Controller
Field Current
Controller
-N set
set
-
-Iact,q
Iset,q
Iset,q
-Iact,q
Operating type “Vector”, Encoder based
Vector Control
G

38. Closed-loop vector control with encoder is required for
Very high accuracy of the speed
Very dynamic applications
Torque control of a control range from Zero Speed to Rated Speed
Encoder
An encoder, also called a shaft encoder, is an electro-
mechanical device that converts the angular position or motion of a
shaft or axle to an analog or digital code.

40.  Centrifugal Pump
 Volts/Hz
 Fan
 Volts/Hz
 Positive Displacement Pump
 Vector
 Extruder
 Vector or Vector with Encoder
 Crane - Hoist
 Vector with Encoder
 Crane - Bridge
 Vector or Vector with Encoder
 Crane - Trolley
 Volts/Hz or Vector

41.  Winder - Payoff Stand
 Vector with Feedback
 Winder - Rear Drum
 Vector with Feedback
 Winder - Front Drum
 Vector with Feedback
 Winder - Slitter
 Volts/Hz
 Wind-up Roll
 Volts/Hz
 Shafted Printing Press
 Vector or Vector with Encoder
 Stamping Press
 Vector with Encoder

42.  Conveyors
 Volts/Hz or Vector or Vector with Feedback
 Wire Drawing Machinery
 Vector with Feedback
 Ball Mills, Kilns
 Vector or Vector with Feedback
 Plywood
 Vector with Encoder
 Lathe
 Vector with Encoder
 Synchronizing to the AC Line
 Vector with Encoder
 Speed Mode / Torque Mode Transfer
 Vector with Encoder

43. Sinamics
G120
Drives

44. Benefits of VFD
• Variable Speed
• Motor Protection
• Energy Saving
Additional Benefits of VFD
• Process parameters like temperature, pressure or flow without
use of a separate controller.
• 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.

45. Commissioning
 FACTORY DEFAULT:
P0003 = 3
P970 = 1
PARAMETER ACCESS
3 = Expert Level
START PARAMETER RESET
0 = Parameter Reset
1 = No Parameter Reset
P0010 = 30
Commissioning Menu
30 = Setting of default parameters

46. P0003 = 3
 MOTOR DATA:
P0010 = 1
PARAMETER ACCESS
3 = Expert Level
Commissioning Menu
1 = Setting of Motor parameters
P0010 = 0
P0304 = _______
P0305 = _______
P0307 = _______
P0310 = _______
P0311 = ________
Motor Voltage
Motor Current
Motor Power
Motor Frequency
Motor RPM
Commissioning Menu
0 = Return to operation Mode