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SPARKS
ELECTRICAL NEWS
SEPTEMBER 2016
DISTRIBUTION BOARDS, SWITCHES,
SOCKETS AND PROTECTION
16
AFRICA’S LARGEST PLUG AND SOCKET
MANUFACTURER
UNDER ONE ROOF
THREE-POLE SF6 CONTRACTOR
TO THE
SOUTHERN AFRICAN MARKET
COMPONENT,
equipment and system engineering special-
ist, Powermite’s range of electrical products manufactured
locally by Ampco and Proof Engineering, are now combined
under one roof in a new state-of-the-art manufacturing fa-
cility, enhancing products and service delivery.
“Pooling the talents and resources across both busi-
nesses has created the largest plug and socket manufac-
turer under one roof in Africa,” says Powermite marketing
director, Donovan Marks.
The range of electrical products, hazardous lighting
products and components from Proof Engineering and
Ampco, part of Powermite, a Hudaco Group company, are
used on mobile generators, pumps and welding machines
marine, industrial and general engineering applications as
well as on mining machinery operating in underground
and opencast mining such as continuous miners, shuttle
cars, pumps, tunnel borers and transformers.
As a leading industrial plugs and sockets manufacturer
for over 30 years, Ampco produces products renowned
for their quality, reliability and safety. The unique inter-
locking design prevents the end-user from removing the
plug under load while the application of LM 6 reduces
the possibility of corrosion and extends product lifecycle.
Proof Engineering produces plugs and sockets as well
as tunnel couplers and adaptors for underground and
open cast applications, couplers for draglines and more
recent additions, couplers and adaptors for overhead line
skids.
Manufactured from non-theft material which con-
sists of a combination of zinc, copper and aluminium,
the unique ProAlloy coupler is 33% lighter than its brass
counterpart and most importantly, holds no resale value.
“The subsequent reduction in theft risk lowers the poten-
tial for unplanned downtime and subsequent production
losses,” explains Marks.
Proof Engineering through Azolite, recently introduced
a range of energy saving LED lighting solutions for haz-
ardous tunnelling and underground mining applications.
The new Azolite LED fluorescent lights have been fitted
with an emergency back-up LED and a small charger
which will continue to provide light for up to 12 hours.
The range also includes a non-hazardous blue LED light
which has the capability of shining through heavy dust,
making it ideal for applications such as underground res-
cue bays.
Enquiries: +27 11 271 0000
SCOPE,
represented in South Africa by Instrotech Test & Measurement, has introduced
its next generation of iconic Scot series circuit breaker time interval meters in all new
super-light avatars, based on cutting-edge microcontroller and embedded technology.
Scot incorporates some state-of-the-art hardware and smart software features making
it a must-have tool for testing and maintenance engineers for quick assessment of the
operational health of circuit breakers.
It’s a compact, lightweight and reliable instrument used for measurement of
operation times of all types of HV and EHV circuit breakers under live switchyard
conditions.
Users can choose from two models: Scot M3K+ and Scot MXP+ depending on type
of testing to be done on circuit breakers.
Scot M3K+ measures and displays ‘close’, ‘open’, and C-O times of main contacts
of three-poles connected end-to-end, simultaneously; and is ideally suitable for CBs
with single break per pole.
Scot MXP+ measures, displays and prints ‘close’, ‘open’ and C-O times of two main
plus two PIR contacts per pole, three poles simultaneously, ensuring measurement of
six main plus six PIR contacts simultaneously; and is ideally suitable for CBs having
PIR contacts and multiple breaks per pole.
Measurement
Proper functioning of CBs is of vital importance to ensure safety and availability of power
network. These are expected to operate reliably and within specified time limits in order
to isolate the faults and save expensive equipment from stress or damage. In order to
be assured of such consistent performance of CBs, periodical timing measurements are
carried out.
Scot is connected to give command to CB for ‘close’, ‘open’ or ‘close-open’ opera-
tion and timings in milliseconds are directly obtained for main as well as PIR * con-
tacts (Scot MXP+). The non-simultaneity of operation of poles as well as contacts*
can be verified.
Special features
• Radical new design makes Scot the lightest CB time interval meter available.
• High sampling frequency of up to 10 KHz offers high timing resolution of 0.1 mS.
• Mains as well as rechargeable Li-ion battery operated. In-built battery monitor and
cut-off circuit for protection against battery deep discharge.
• In built real time clock, memory and printer*. Test time stamping on each record ena-
bles time references for future use.
• PC downloading and analysis including ‘trend analysis’ possible with CData Scot soft-
ware supplied with kit.
• Create CB identification data (CB Library) on PC and upload to instrument. Save the
test results in respective CB folder in kit. Download the same to PC in similar folder
structure.
• Instrument debug options like contact status check, command check, memory check,
printer check*, PC downloading check are provided.
• Simple operation. Tests can be conducted even by technicians.
• Supplied with rugged test lead set, suitable for testing EHV CBs.
• Enclosed in a rugged IP67 hard moulded case.
* These features are available only in Scot MXP+.
Benefits
• Understand the non-simultaneity of pole and break operation.
• Battery operation enables measurement in absence of ac supply, especially useful on
under-construction sites.
• Proven reliability in EHV switchyard environment.
• Suits utilities, OEMs, test labs as well as testing and commissioning companies.
Enquiries: +27 10 595 1831
New generation
circuit breakers
time internal meters
S
chneider Electric has introduced its Rollarc three-
pole indoor contactor, which uses sulphur hexafluor-
ide (SF6) gas for insulation and circuit-breaking, to
the southern African market. The Rollarc is available in two
versions; the Rollarc R400 comes complete with magnetic
holding, while the R400D is accompanied by mechanical
latching.
According to Brighton Mwarehwa, technical manager
at Schneider Electric South Africa, the circuit-breaking of
the Rollarc unit is based on the rotating arc principle. “The
basic version is made up of three pole units installed in
the same insulating enclosure. The part of the enclosure
containing the active parts of the poles is filled with SF6
gas at a gauge pressure of 2.5 bars,” he explains.
Mwarehwa points out that the main advantages of the
Rollarc contactors include a modern and tested circuit-
breaking technique featuring SF6 safety, no maintenance
for the MV active parts, high mechanical and electrical
endurance, low switching surges without additional de-
vices, insensitivity to the environment and that gas pres-
sure may be continuously monitored. The Rollarc range
is ideal for the protection and control of medium voltage
motors, capacitor banks, power transformers, resistors
and general switching.
“The unit is also insensitive to external conditions and
provides a complete gas-insulated system. It is a her-
metically sealed enclosure, filled with SF6 gas, housing
the essential parts. Rollarc is suited to most environ-
ments, including polluted environments such as mines,
cement works, and more,” adds Mwarehwa.
Both the Rollarc R400 and R400D contactors are
available in three versions:
• The basic version: contactor alone, without the cradle;
• The fixed version: the contactor with the control auxilia-
ries is mounted on a fixed cradle; and
• The withdrawable version: the contactor with the control
auxiliaries is mounted on a withdrawable cradle.
“Fixed and withdrawable versions may be equipped with
fuses when the system short-circuit current is greater than
the contactor short circuit rating. The common fuses used in
the Rollarc contactors are of the indoor Fusarc CF type with
strikers that actuate the contactor opening mechanism,”
says Mwarehwa.
The Rollarc rotating arc contactor has the following
benefits:
• Long life:
This results from high product reliability, very
low wear of the active parts which require no mainte-
nance, and the excellent sealing of the enclosure, elimi-
nating the need for subsequent filling.
• Mechanical endurance:
The operating energy is reduced
because the current to be interrupted, directly creates arc
rotation. The Rollarc contactor can do up to 300 000
operations in R400 version and 100 000 operations in
R400D version.
• Electrical endurance:
The long life of the Rollarc is due to
the negligible degeneration of the gas and to low wear of
the contacts. The energy dissipated in the arc is low due
to the intrinsic properties of the gas, the short length of
the arc, and the very short arcing time.
“Wear of the arcing contacts can be checked without open-
ing the poles. The unit is capable of breaking normal load
currents and short circuit currents up to its rating, even in
the case of frequent operation. In the case of higher short
circuit currents, the Rollarc contactor can be used in fuse-
contactor assembly enabling the contactor to deliver much
more,” continues Mwarehwa. “The intrinsic properties of the
gas and the soft break resulting from the technology in use,
mean that switching surges are very low. When used for
motor control, the unit is free from multiple prestrike and
restrike phenomena.”
In addition, in the unlikely event of an accidental drop
in the pressure of the SF6 gas in the Rollarc unit, there
is an option for a pressure switch for alarm indications
and control.
Enquiries: +27 (0) 11 254 6400