Electric Motors Fact Sheet

7/30/2019 Electric Motors Fact Sheet

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Energy Saving Fact Sheet | Motors


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Motors are cheap to repair, so having them rewound and

reconditioned is often the automatic choice whenever they

break. But consider:

The true cost (in most cases). A rewound motor is

usually less energy-efficient than a new one. Although

the cost of a rewind will be lower than buying a new

motor, the increased running costs will quickly wipe out

your initial saving.

Dont skimp. A rewound motor could cost you more long

term in breakdowns and lower reliability. Factor this into

your purchase decision.

Get advice. Ask your motor supplier to calculate the

energy you would save by buying a new motor compared

to repairing an old one.

Fitting the right drives now can save up to 50% in energy.

Its that simple.

Think efficient. Always specify high-efficiency motors

(HEMs). They rarely cost more but use 3-5% less energy

and qualify for 100% tax relief under the Enhanced

Capital Allowance scheme.

Plan ahead. Create a motor management plan for buying

and repairing motors. A structured approach will reduce

downtime and cause less disruption to your operation

when motors do fail.

Not too big. Many motors are hugely over-sized for the

machines they power. Check the equipment and buy a

motor that matches the load requirements, plus a small

margin of error.

Energy Saving Fact Sheet | Motors

Power your way to greater energy savingsMotors are everywhere in industry and business. Since they power almost everything, from

pumps and fans to compressors, theyre serious energy users. But of course, they offer major

scope for energy saving which is where this practical fact sheet can help. It will enable you

to identify areas where you can save money, and make your business more efficient, too.

Energy wasting hot spots

Want to know where you can save energy? Theres no better

place to start than motors and drives, as these account for

over two-thirds of power used in industry. For many more

helpful hints, simply call the Carbon Trust on 0800 085 2005.

Breakdown of electricity use across industry

fact:A motor runn

ing for 11 hours a day

(4,000 hoursa year) at a t

ypical

commercial or industrial s

ite costs

ten times more in electric

ity than

its capital cost.

Repair, rewind or replace

Lighting

Motors

and drives

Other

Buying and installing


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What you should know about motor efficiencyMost motors operate using AC (alternating current) induction they use electricity

to generate magnetic fields that turn the motor. Some energy is lost within the motor

through friction and magnetic losses, so no motor is 100% efficient. On the other hand,

new higher-efficiency motors can be more than 90% efficient.

Hidden costs

The cost of an electric motor can be very deceptive;

in particular, the annual energy cost to run the motor

can be up to ten times its purchase cost. Running costs

of a fully-loaded motor can range from 1,000 a year

for a 2.2 kW motor to 18,000 a year for a 37 kW one.

Small differences, big savings

When you consider running costs and efficiencies together,

its clear that buying the most efficient motors and ensuring

that they are properly maintained can save a large amount

of money. For example, a 10 kW motor operating at 87%

efficiency could cost 75 more per year to run than one

that is just 5% more efficient. Over the motors lifetime,

the less efficient motor would cost 1,500 more than the

higher-efficiency model.

Common sense and forward thinking can help you save

thousands of pounds in energy a year.

Maintain well. Motors work hard and become less

efficient over time through wear and tear. Check your

drive systems and alignment regularly to extend their

useful life.

Automate it. Think about automated process control

systems to manage motor speeds. This can save up to

15% of a process running-cost.

Switch off. Always the cheapest way to save energy

turn motors off when theyre not in use, provided this

is in line with the machine manufacturers guidelines.

Many motors are connected to machinery with gears, pulleys

or belts but this can be wasteful. Here are some solutions:

Go direct. Energy can be wasted when it is transmitted

through a drivetrain. If possible, choose directly-

connected motors running at the right speed this is

much more efficient.

Maximise efficiency. Ensure that drivetrains operate

as effectively as possible by checking and maintaining

regularly belt tension and gear lubrication.

Line them up. Check the alignment of gears and other

linkages. Youll avoid the loss of hundreds of pounds over

the lifetime of the motor. Even a small misalignment will

reduce system efficiency by several percent costing

you money.

Day-to-day operation Drivetrains


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Look at every motorLike many businesses, you probably have motors that are part of the furniture;

they are tucked away in all kinds of places and their operation is no longer

noticed. However, you can make significant energy and cost savings by examining

each motor system and how it is used; the diagram below will help you identify

the various options.

Five questions

For each motor on your premises, ask the following:

1. Can the motor be switched off?

2. How can motor efficiency be improved?

3. Is the motor correctly sized?

4. Can the speed of the motor be reduced?

5. How can good maintenance improve efficiency?

The results will enable you to make all kinds

of operational improvements.

The Carbon Trust 0800 085 2005 www.thecarbontrust.co.uk/energy

One of the best ways to save energy with motors

is to fit variable-speed drives (VSDs) to units that

need to operate at a range of speeds.

Quick, slow, save. It can be wasteful to drive every

motor at the maximum speed all the time. VSDs

enable the motor to be driven at different speeds in

order to match the load required by the equipment

or application. This is important because lowering

the speed of a motor by just 20% can save up to

50% in energy.

More cost-effective. Many types of motor-driven

equipment are now available with built-in VSDs.

These include air conditioning units, pumps and

fans. Buying equipment that incorporates a VSDis usually cheaper than acquiring the equipment

and the VSD separately.

Variable speed drives

Ask whether the system

is doing a useful job

Reduce

system

losses

Select the

driven

machinery

for best

efficiency

Select the

motor for best

efficiency

Reduce

transmission

lossesSlow it

down

Switch

it off

This diagram shows a system in which a motor

drives a pump to recycle liquid from process

to a feed reservoir

Improved control. As well as slashing energy bills,

VSDs offer a wide range of speed, torque and power,

and give improved process control. That means

added flexibility and quality across your plant.

Distributed power. Installing VSDs can prove even

more attractive when you realise that a single drive

is often able to control several motors at once.


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Start saving energy today

Allocate responsibility to a member of staff or small team who can drive

forward energy saving measures, such as:

1. Power down. The cheapest way to save energy from motors is to make sure

that they are turned off when not in use!2. Go slow. Fit variable speed drives (VSDs) wherever possible to match motor

speed to the load.

3. Use forward thinking. Write a basic motor management plan to ensure a

structured approach to the purchase and repair of your companys motors.

4. Look at the real costs. Make purchase decisions based on operating costs,

not on initial cost. The annual cost of running motor can be ten times its

purchase cost.

5. Get your hands dirty. Motors work hard and lose efficiency through wear

and tear. Good maintenance saves money.

Call the Carbon Trust for a copy ofHow to select a variable speed drive ourstep-by-step guide to energy saving. We can also give you further energy saving

advice for your business.

The Carbon Trust 0800 085 2005 www.thecarbontrust.co.uk/energy

More ways to save

Take action!

ECA and Energy-Efficiency Loans

If youre considering installing a new motor orcomponents, buy from the approved Energy Technology

List (at www.eca.gov.uk). This details products that meet

certain energy efficiency criteria. You may also qualify

for a valuable Enhanced Capital Allowance and an

interest-free loan from the Carbon Trust. Call 0800 085 2005

for more information.


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The Carbon Trust is funded by the Department for Environment, Food and Rural Affairs, the Scottish Executive,the Welsh Assembly Government and Invest Northern Ireland.

Whilst we have taken reasonable steps to ensure that the information contained within this leaflet is correct,

we give no warranty and make no representation as to its accuracy and we accept no liability for any errors

or omissions and neither does the Government.

The Carbon Trust is a company limited by guarantee. Registered in England and Wales Number 4190230.

Registered at: 8th Floor, 3 Clements Inn, London WC2A 2AZ.

Queens Printer and Controller of HMSO, March 2006

The Carbon Trust helps businesses and public

sector organisations cut their energy costs to

combat climate change through the provision

of free, professional advice and assistance.

Want to find out more?

You can obtain these energy saving guides at

www.thecarbontrust.co.uk/energy or by calling the

Carbon Trust on 0800 085 2005.

GIL056 Energy savings from motor management policies

GIL152 How to select a variable speed drive

Weve got many more tips on motors and drives that will

help you save energy and money. So give the Carbon Trust

a call today.

GIL128 v2

The Carbon Trust 0800 085 2005

www.thecarbontrust.co.uk/energy

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Electric Motors Fact Sheet