DRIVES, MOTORS + SWITCHGEAR
ROUND UP
Marthinusen & Coutts
, South African based repairer of rotating electrical equipment and a
division of Actom, has successfully installed four mill motors at a copper mine in North-West
Zambia. The massive electric motors, with diameters of 40 and 28 feet respectively, and with
each stator quadrant weighing approximately100 tons, are the largest M&C has helped install
to date and probably the largest in Africa. Marthinusen & Coutts’ scope of work comprised the
installation of stator quadrant windings on the four mill motors, which were manufactured by
Siemens, Germany. The motors are Gearless Mill Drives (GMDs), also known as wrap-around
motors, and include two 26 MW Ball mill motors and two 28 MW SAG mill motors.
Among the challenges on this project were the remote location of the mine, approximately
400 km north-east of Kitwe, and working during a heavy rainy season while trying to meet an
incredibly tight deadline.
Marthinusen & Coutts was able, at short notice, to mobilise a team of highly skilled techni-
cians to undertake the winding of the 16 quadrant joints on the motors. Each joint on the motor
has seven large (uninsulated overhang) ‘flexible’ coils, which are used to help contend with the
connecting of the stator coils at the quadrant interfaces, while the balance of the coils are normal
resin-rich set diamond type coils, each weighing 44 kg.
A 20 foot container, equipped with the correct tooling and test instruments, was dispatched
to the site. Each SAG mill motor was completed in less than 25 days, while the ball mill motors
were completed in less than 23 days.
“We’re well versed in carrying out site work in remote locations on theAfrican continent,” Rich-
ard Botton, Marthinusen & Coutts divisional chief executive officer, says. “We fully understand the
various work practices and cultures of the local people and we’re able to draw on a well-established
network to deal with complicated cross border protocols. Marthinusen & Coutts owns and man-
ages a fully functional
service shop in Kitwe
with technicians on call
to support our custom-
ers in the region.
Enquiries:
Richard Botton.Tel.
011 607 1700 or email
The KD and KE models from
NewElec
are comprehensive low voltage electronic motor protec-
tion relays designed for conveyor, compressor, crusher, fan and pump motor protection. The
relays boast a wide range of user-selectable protection features and redefine basic protection
and motor management expectations at an affordable price. The powerful, low voltage three-
phase relays provide protection for overloads with user-selectable thermal curves, load loss with
a user-selectable measurement method and intelligent
short circuit trip levels, dependent on power-factor
measurement. The KD relay facilitates certain control
panel mounted settings while the paramatisation of the
KE is fully software driven. KD and KE relays provide
programmable starts per hour and permissible consecu-
tive starts, 2 000 event records and 60 last fault events
with complete details relating to current and voltage
values.The relays also provide software based real time
recording capabilities.
Enquiries: Luc Dutrieux.Tel. 012 327 1729
or email
Installation of stator coil connections on mill
motors in Africa
3
in
1
LV motor protection relays
