Sparks Electrical News September 2016

DISTRIBUTION BOARDS, SWITCHES, SOCKETS AND PROTECTION

16

AFRICA’S LARGEST PLUG AND SOCKET MANUFACTURER UNDER ONE ROOF

New generation circuit breakers time internal meters

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, 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

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.

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.

Enquiries: +27 11 271 0000

THREE-POLE SF6 CONTRACTOR TO THE SOUTHERN AFRICAN MARKET

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.

• 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 (0) 11 254 6400

Enquiries: +27 10 595 1831

SPARKS ELECTRICAL NEWS

SEPTEMBER 2016