Johannesburg - The barring gear motor at unit one of the Kusile power station was switched on this week, Eskom said on Tuesday.
“This is a critical milestone following on the heels of the lubricating oil flush process that was achieved in September,” the parastatal said in a statement.
A barring gear motor is a gear mechanism which ensures a turbine does not bend once it is in position, Eskom spokesman Andrew Etzinger said.
The motor turns at 2400 revolutions per minute (rpm) through a reduction gearbox which in turn rotates the turbine at 16 rpm.
“This gives assurance that the whole rotor train is free to rotate,” Eskom said.
Alstom Power managing director Lee Dawes and Kusile's project director Abram Masango switched on the barring gear motor on Monday.
The Kusile coal-fired plant, which is being built near Emalahleni, Mpumalanga, is expected to add 4800MW to the electricity grid on completion in 2017. It has six 800MW units.
In October, Eskom said the power station's unit six would see first-power-to-grid in the second half of 2015.
It was initially scheduled to make its first contribution to the grid this year.
Unit six of the Medupi power station, Eskom's other coal-fired plant, received a pressure equipment regulation certificate from the labour department earlier this month.
Unit six of the new power station, which has faced numerous construction delays, is expected to be synchronised on December 24.
Synchronisation, or first power, involves the generator being electrically connected to the power grid, so that its power is aligned with all the other generators to deliver electricity into the grid.
It would take several months for the unit to reach full and stable power.
Sapa