Electricity + Control May 2016

DRIVES, MOTORS + SWITCHGEAR

ROUND UP

Aluminium three-phase 380V and 525V motors for industrial applications The main benefit of the Bauer range of aluminium electric motors is that it is far more lightweight than its cast-iron equiva- lents due to the aluminium casing and end shield, Lewis Hiepner, product manager: electric motors at BI, comments. manufacturing process use a vacuum pres- sure impregnation system in the insulation. The motors are also IP55 weather-proof, meaning that they can withstand normal weather conditions, provided that the cable termination to the terminal box is carried out correctly.The Bauer range is also water, dust and even vermin proof.

The ac brake type is specifically for instant stopping when the power is switched off. Applications include bottling plants where accuracy in the stopping position is critical. Dc brakes, on the other hand, are slower in reaction time. This is due to the brake’s power going through a rectifier in order to convert ac to dc, with a resultant delay.Typi- cal applications include overhead cranes, where stopping accuracy is not as critical. All Bauer motors conform to the relevant IEC standards, as well as being designed for S1 duty.This means that the motors can run continuously for 24 hours under normal load conditions. Another feature is the Class F insulation, with a ‘B’ temperature rise (80°C plus a maximum ambient tempera- ture of 40°C, giving a total of 120°C). The

“This MS range of aluminium three- phase 380 V and 525 V motors has been supplied successfully to the South African market for the past decade,” Hiepner points out. A main feature is the multi-mount de- sign, with the added benefit of being able to change the feet on-site.This gives the cus- tomer the option of having the terminal box on the top or on the left or right hand side, depending on the specific requirements. In addition, Bauer motors can be fitted with an external brake of either an ac or dc type. Drives for Masama wellfields Rockwell Automation recently supplied medium voltage drives and soft starter motors for Masama wellfields – located about 80 km northeast of Gaborone in Botswana. The hardware was in- stalled in February 2015 and commissioned in June, with the wellfields commencing operation in September 2015.The completion of theMasama wellfieldsmeans an additional 20Ml/day will sup- plement the existing 60 Ml/day supply of water that is delivered through the North South Carrier 1 pipeline. It represents a significant milestone in the country’s ability to attain long-termwater security. The RockwellAutomation scope of the project was mainly as product vendor, and related equipment design and commissioning. The company sup- plied two PowerFlex 6000MV ac drives (1 150 kW, 6,6 kV) that will automate the pump system that transfers water from holding tanks to the North South Carrier 1 pipeline. Ducting for the drives was engineered-to-order tomaximise airflowover the drives to deal effectively with the heat. Allen- Bradley SMC Flex Soft Starterswere also supplied, one for each of the 32 boreholes.The soft starters will play an integral role both in providing motor protection and in optimising the energy consump- tion of the wellfields. Rockwell Automation has been involved in previous phases of the 360-km North South Carrier pipeline.The PowerFlex 6000 supplements the Rockwell Automation MV drive range, providing a cost-effective, fit-for-purpose drive for new and retrofit centrifugal fan and pump applications rated up to 10 kV.

Enquiries: Gugulethu Nkutha. Tel. +27 (0) 11 899 0000 or email gugulethu@bearings.co.za

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