soft start uk guide to energy saving new

April 2010

Energy Saving in Automation & ControlEnergy Saving in Automation & Control

INTRODUCTION TO Softstart UK

Softstart UK is an Industrial Automation supplier and system builder. Having a warehouse with VFD’s to 75KW and Soft Starters to 400KW available ex-stock.We have a training facility in Great Yarmouth with an extensive stock level of automation products including PLC’s, HMI’s, Power Supplies, AC Servo, and Power Quality products..

April 2010


HOW MUCH HAS YOUR ENERGY COSTS

INCREASED IN THE LAST 12 MONTHS?

All AC motors cost money £££ example: (A 22kW fan running continuously 24hrs a day, 365 days a year costs on average £7,708)

AC Motors are responsible for 70% of UK Industries energy bills.

The Climate Change Levy applies an additional 15% surcharge to all heavy and light industrial consumers.

On average 70% of industrial fan, pump and consumer applications would benefit by using a modern AC Variable Speed Drive both through process and energy saving benefits.

Payback can be as little as 3-4 months on some fan and pump applications.

April 2010


INTRODUCTION TO VARIABLE SPEED DRIVES

What is a VSD

Where to use VSDs

Example application for VSDs

April 2010



Poles 50Hz 60Hz

2 3000 3600

4 1500 1800

6 1000 1200

8 750 900

RPM =120 x f (Hz)

Poles

April 2010


Pressure

Temperature

Variable SpeedDrive

Motor Protection

Communications


The Intelligent Motor

April 2010


Energy saving ability PID Control with sleep modes Built in 10K step PLC Multi-pump control Improved process control Near-DC performance without the maintenance Good power factor Built-in soft-start Built-in energy optimising Controllable via a BMS or PLC


The Benefits

April 2010


Flow proportional to the speed

Pressure proportional to the speed squared

Power proportional to the speed cubed


Fan Affinity Laws

April 2010



Cube Law Characteristic

Speed (%)

Inpu

t Pow

er (%

)100

0

80

60

40

20

010 20 30 40 50 60 70 80 90 100

April 2010



Power Consumption & Power Saved

Percent Flow

Pow

er

50 100 150

Fixed speedpower input

0

Power saved

Power inputto drive

Power lossin pump,motor andVSD

Useful powerto producesystem flow

April 2010


Flow Rate (%)

Inpu

t Pow

er (%

)

10

10 20 30 40 50 60 70 80 90 100

2030405060708090

100110120130140

DamperInlet Guide Vanes

Disc Throttle

Ideal Fan Control

Variable PitchAxial FanPWM Inverter


Fan Power Requirements with different methods

April 2010


Look for: . . .

Centrifugal Fans and Pumps

Systems with a low static head

Compressors


Saving Energy with VSD’s

April 2010


A VSD controls the speed of the motor to match the load imposed on it under varying process and environmental conditions. As power consumption is proportional to the cube of the motor speed, significant savings can be achieved. Although several industrial applications can benefit from inverter control, the most significant savings can be made with centrifugal loads such as fans and pumps.

Typical Saving Calculations;

Motor running costs £ Cost of Electricity to run the motor for 1 year.

Motor power kW Power rating of motor.

Run Hours Number of hours run for 1 year assumed to be 1 x 365 x 24 = 8760 hrs.

Cost of electricity Assumed to be 4p/unit. One unit equals 1kWhr

Energy Saving factor Fans and Pumps operate on a cube law principle the energy saved reduces bythe cube of the speed reduction therefore a motor running at 50% speed will use0.5 x 0.5 x 0.5 of the power ie: 0.125 or only consume 12.5% of the normal power.

Savings Savings are the difference between the normal running costs and the runningcosts with an inverter.

Pay Back The number of months taken to pay for the cost of an inverter and installation.

VARIABLE SPEED / ENERGY SAVING

April 2010


Formula;

Motor Running Costs = Motor Power x Saving Factor x Hours Run x Electricity Costs

Savings = Normal Running Costs – Inverter driven running costs

Pay Back in months = (Cost of Inverter ÷ Savings per annum) x 12

Example;

45kW Centrifugal Pump running continuously. Calculate normal running costs and cost when driven by an inverter at 90% for 8 hours a day and 50% for the remaining part of the day.

DOL Motor running costs = 45 x 1 x 8760 x 0.04 = £15768 per annum

Inverter running costs = (45 x 0.729 x 2920 x 0.04) + (45 x 0.125 x 5840 x 0.04) = £5156 per annum

Savings = £15768 - £5156 = £10612 per annum

Typical cost of 45kW Inverter = £2795

Pay Back = (£2795 ÷ £10612) x 12 = 3.16 months


April 2010



Some newer technology Inverters provide additional energy saving features which provide further savings.

The graph below shows detail of the automatic energy saving function available from the Hyundai N300EFrequency Inverter. This function insures that the motor operates at minimum current in response to the torque required by the load.

April 2010


www.eca.gov.uk


April 2010


INTRODUCTION TO SOFT STARTERS

What is a Soft Starter

Where to use Soft Starters

Example application for Soft Starters

April 2010


AC Input SupplyFixed Supply FrequencyUK = 50HzSingle Phase 240VThree Phase 415V

Soft Starter Thyristor OutputVarying Voltage

Motor Fixed SpeedRamped StartRamped Stop


April 2010


Digital Control

Soft StarterMotor

Protection

Communications


The Intelligent Motor

April 2010



The Benefits

Advantages: Solid state - no moving parts, less maintenance Reduced starting current & mechanical shock Smooth, step less acceleration & deceleration Closed current loop starting Easy adjustments for all applications Comprehensive motor protection package Special features: “Pump Control”, Soft stop, Slow speed with electronic reversing. Uninterrupted operation of unmanned installations such as irrigators, flood pumps, remote pump stations is aided by the LV-DS soft starter’s Auto-Reset function.

April 2010



The Benefits

Some advanced digital soft starters provide additional features such as;Emergency Run ModeEmergency Run Mode

•In the case of fire, equipment such as ventilation fans in high rise buildings can be required to run at all costs.

•Activation of the LV-DS’s Emergency Run mode initiates a start and deactivates all protections, enabling the motor to run as long as possible despite the deteriorating environment.

April 2010


Look for : . . .

Centrifugal Fans and Pumps Compressors Generator Supply Low Capacity Supply Application requiring reduced mechanical shock


Where to use Soft Starters

soft start uk guide to energy saving new

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