Mechanical Technology January 2015

Mechanical Technology — January 2015

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Power transmission, bearings, bushes and seals

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project delivered by Southeast

Power Engineering of the UK

has seen a mini power station

installed on the River Thames

at Romney Weir to generate electricity

using environmentally friendly water-

driven Archimedes screw generators.

The completed design features two

WEG W22 Premium Efficiency IE3 gen-

erators being driven by the screws via

a gearbox to produce electricity, which

now powers Windsor Castle.

The WEG W22 units are ‘special’

products for this application in the

sense that they are generators based on

the WEG W22 motor. On starting the

rotation of the Archimedes screws, the

W22 draws electricity and is driven as a

motor. Then, once turning at a suitable

speed, the motor function changes over

to that of a generator and the rotation of

the screw is maintained by the water,

which drives the W22 as a generator

in order to produce electricity.

The scheme is the brainchild of

David Dechambeau, managing director

of Southeast Power Engineering, who

has overseen every step of the design

and installation process. “In order to

make this project sustainable, it was

essential that we select the most ef-

ficient equipment for the construction

of this power station. The design called

for a reliable generator with superior

efficiency ratings and, on balance, the

WEG W22 unit definitely fitted the crite-

ria and it was straightforward to install.”

The power station has been generat-

ing electricity since July 2013 and is in

the final stages of testing and commis-

sioning. It comprises two Archimedes

screws manufactured by Landustrie,

each weighing 40 tonnes, connected

to the WEG W22 IE3 class premium

efficiency generators, which can deliver

320 kW at peak flow, exceeding the

original design criteria.

The WEG W22 IE3 generators

were designed and manufactured in

Portugal at WEG’s dedicated European

Above:

A mini power station installed

on the River Thames at Romney Weir

produces ‘green’ electricity by means of

water-driven Archimedes screw genera-

tors based on two WEG W22 premium

efficiency IE3 generators.

Right:

The W22 units are ‘special’

products for this application in the sense

that they are generators based on a W22

motor. At 96% efficiency, they were a

critical part of the power transmission

design to ensure the six-year return on

investment target was met.

Two s p e c i a l l y d e s i g n e d

generators based on WEG W22

premium efficiency motors, are

being driven by Archimedes

screws to produce electricity for

Windsor Castle in the UK.

manufacturing site. They are rated at

185 kW each and produce electricity at

400 V, which is then fed via a 500 kVA

transformer to an underground line that

connects to Windsor Castle and to the

national grid.

Efficiency was a key target for this

application, as the installation has a

fixed return on investment (ROI) period.

At 96% efficiency, the WEG motor/

generators represented one of the best

investments Southeast Power could

make in the power transmission design

to ensure their six-year ROI target was

met. The installation has a minimum

guaranteed design life of 50 years while

Southeast Power has a 40-year tenancy

of the site, which means that reliability

and longevity were also very important

considerations. If the screws stop turn-

ing, there is a direct consequence in

terms of revenue.

“This was a very important project for

us, not only because we are supplying

the Royal Household, but also as an

initial stepping stone for a number of

similar projects. It is essential that we

install the most efficient and ecologically

sound power plant possible. The work

we are completing now will help to

deliver future projects using similar tech-

nology as demand for sustainable power

increases,” Dechambeau concludes.

WEG is represented in Africa by the

Zest WEG Group, a leading supplier of

electric motors, vibrator motors, vari-

able speeds drives, softstarters, trans-

formers MCCs, containerised substa-

tions, diesel generator sets, switchgear

and co-generation and energy solutions

as well as electrical/instrumentation

engineering and project management

services.

The Zest WEG Group operates a stra-

tegically positioned network of support

operations across Africa, which includes

eight branches in South Africa and

operations in Mozambique, Tanzania,

Zambia and Ghana, with distributors

in Botswana, Namibia, Zimbabwe,

Zambia, Kenya, the DRC, Nigeria,

Cameroon, Angola and Mauritania.

WEG W22 generators power Windsor Castle