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TYPES OF LOAD

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CONSTANT TORQUE LOAD :

PERCENT SPEED

NOTE:- A CONSTANT TORQUE LOAD IS NOT NECESSARILY 100% LOAD

TORQUE100

50

50 100

PE

RC

EN

T T

OR

QU

E A

ND

H

OR

SE

PO

WE

R

TYPES OF LOAD

80

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automation4meConveyorsCompressorsRoot BlowersPositive Displacement Pumps

TYPES OF LOAD

CONSTANT TORQUE LOAD :

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VARIABLE TORQUE LOAD :

TYPES OF LOAD

0

20

40

60

80

100

10 20 30 40 50 60 70 80 90 100

SPEED IN %

TO

RQ

UE

& P

OW

ER

IN

%

TORQUE

POWER

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VARIABLE TORQUE LOAD ( Torque Varies as Square of Speed)

TYPES OF LOAD

Centrifugal PumpsCentrifugal Fans 5

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TORQUE100

50

50 100PERCENT SPEED

150 200

TORQUE

HORSE POWER

PE

RC

EN

T T

OR

QU

E A

ND

H

OR

SE

PO

WE

R

CONSTANT HORSEPOWER LOAD :

TYPES OF LOAD

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CONSTANT HORSEPOWER LOAD :

TYPES OF LOAD

• Lathe

• Grinders

• Winders

• Coilers

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ENERGY SAVING APPLICATIONS

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Key Applications Areas – The Energy Guzzlers

• Fans– AHU– Ventilation / Fresh Air – Exhaust– Cooling Tower Fans– ID / FD Fans

• Pumps– Process Water– Pressure booster pumps

• Compressors– Reciprocating, Screw,

Centrifugal

Energy Savings

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Air flow control of fan

Outlet side damper Inlet side

damper

FAN APPLICATION

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Comparison of motor power for fan drive system

100

050 100

Airflow or motor speed (%)

Shaft or power consumption

Energy saving

Inverter control

Shaft power for speed control

Damper control

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Flow Control-Affinity Laws

• Flow Speed

• Pressure / Head Speed 2

• Power Speed 3

Benefits of Flow Control…Benefits of Flow Control… 12

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Fundamentals- Traditional

Flow control is achieved by riding the pump or the fan curve…Flow control is achieved by riding the pump or the fan curve…

ThrottleThrottle

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Flow control is achieved by riding the System Curve…Flow control is achieved by riding the System Curve…

Fundamentals- Evolution

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PR

ES

SU

RE

VOLUME

THROTTLE CONTROL

B

A

O

F

E

D

C SPEED CONTROL

ENERGY SAVING

= SHADED REGION

= AREA (OEAD) - AREA (OFCD)

PRINCIPLE - ENERGY SAVING BY SPEED CONTROL OF PUMPS

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The energy saving effect to the pump type

00.5 1.0

Flow rate Q (P.U.)

Head H (P.U.)

Axial pump

As shown in the figure, the sharper the pump characteristic is i.e., the bigger the comparative speed is, the bigger the 1st energy saving effect becomes.

1.0

2.0

Energy-saving effect

mixed flow pump

Centrifugal pump

System resistance

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PRINCIPLE - ENERGY SAVING BY SPEED CONTROL

As Per Affinity LawsAs Per Affinity Laws

Flow (%)Flow (%) HP (%)HP (%)

RequiredRequired

100100 100100

7575 4242

5050 12.512.5 17

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Compressor

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Compressors• Operates in a load/ unload cycle.

Time

Load

100%

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Conventional compressor system work between two set pressures, resulting in pressure generated being higher than the pressure required in the system.

TIME

PR

ESS

UR

EP

OW

ER

110PSI

90PSIMINIMUM SYSTEM

PRESSURE REQUIRED

20 PSI

100% FULL LOAD POWER DURING LOAD CYCLE

20-30% OF FULL LOAD POWER DURING UNLOAD CYCLE

LOAD UNLOAD

TIME

100PSI

Compressor–Load/Unload Control

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Energy consumption as high as 20-30% of full load power during unload period.

Pressure in the system is much more than the minimum system pressure required, resulting in extra power consumption and wear and tear of the mechanical system.

20PSI extra pressure in the system, results in 10% extra power consumption.

DOL or star/delta starting sequence on a motor creates a power surge in electrical system.

Disadvantages of Traditional Compressor:

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Typical Schematic

AC MOTOR AIR COMPRESSOR

AIR

RECEIVERVARIABLE

SPEEDAC DRIVE 4-20 mA/ 0-10V PRESSURE FEEDBACK SIGNAL

3 Ph./ 415V Supply

ToPlant

PRESSURETRANSMITTER

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Variable pressure setting possible.

Accurate pressure control.

No unload cycle, thus reducing power consumption typically by 20 to 30% of full load power.

Soft start with inverter control, power to the motor is increased progressively, avoiding peak power demand in the electrical system.

Advantages with Inverter Control:

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