Leading local repairer of rotating electrical equipment, Marthinusen & Coutts says its in-house ability to precision balance rotors to a high accuracy improves vibration levels, thereby increasing reliability while reducing customer maintenance costs. Marthinusen Coutts, a division of Actom, operates the third largest high speed dynamic balancing machine in sub-Saharan Africa. Mike Chamberlain, marketing executive at Marthinusen & Coutts, says the advanced machine is in constant use with local OEMs benefitting tremendously by having such access to an independent balancing service of this quality and capacity.

The 32 ton Schenck HM7 U/S balancing machine is located at Marthinusen & Coutts’ 9 500 m² high tech workshop in Cleveland, near Johannesburg. The HM7 U/S balancing machine is 9 000 mm long and has a measuring range between 100 and 5000 r.p.m.. It has a journal size of 400 mm and a swing of 2 400 mm. It is fitted with a CAB 920 H measuring instrument with a vector display. Its state-of-the-art technology makes changeovers to new rotor types quick and straightforward. “The machine facilitates the balancing of all larger high speed rotors dynamically at full operating speed and sometimes, depending on the design of the rotor and customer requirements, at 10% overspeed,” Chamberlain says.

All rotors are balanced in-house which speeds up the process and reduces costs with the service being available to external customers on a first come, first served basis. The machine is operated by one of the country’s top balancing machine experts in line with international best practice with industry standard balancing certificates being issued for each completed rotor. The largest rotor balanced at full speed to date was a 15 ton 4 pole rotor for a 28 MW compressor motor used by a leading local steel producer.

Marthinusen & Coutts provides this crucial service to the power generation industry balancing both high pressure and low pressure turbines. The division has also partially (low speed) balanced generator rotors up to 60MW where the rotors are subsequently trim balanced at full speed on site, once the rotor has been installed.

“It goes without saying that the service has obvious time and expense advantages for those making use of it,” Chamberlain concludes.