In the rewinding and uprate of a 40 MVA (uprate to 46 MVA), 13.8 kV, 3-phase, 60 hz, one circuit, wave winding, hydro generator, the mean length turn has increased to achieve bar end arm and cross over clearances of 1/2". This resulted that the overhang portion of the bars (winding) was elongated by about 6 inches at the turbine end and 5 inches at the connection end.
The Contractor wanted to move the air baffles away from the winding by the same distance to keep the existing striking distance.
The question is what is the minimum striking distance between the winding and the airbaffles for an 8 kV (Line to Ground) machine?
Is there a formula to claculate the minimum and a safe striking distance at different voltages and is there a Stnadard or a Guideline to follow for deciding this distance?
Thank you for your input and for sharing your expertise.
The Contractor wanted to move the air baffles away from the winding by the same distance to keep the existing striking distance.
The question is what is the minimum striking distance between the winding and the airbaffles for an 8 kV (Line to Ground) machine?
Is there a formula to claculate the minimum and a safe striking distance at different voltages and is there a Stnadard or a Guideline to follow for deciding this distance?
Thank you for your input and for sharing your expertise.