BMW Sauber has concluded its investigation into the alarming incident in late July when one of its mechanics received an electric shock during testing at Jerez after touching a car fitted with a Kinetic Energy Recovery System (KERS).
The mechanic escaped with only minor grazing to his left hand and arm, but the incident prompted fresh concern over the safety of the KERS devices after Red Bull Racing had already suffered a fire scare at its factory triggered by a battery failure.
After what it described as "an extremely far-reaching" inquiry BMW has revealed details of what caused its incident.
"The mechanic suffered an electric shock after touching the sidepod and steering wheel of the car," said Markus Duesmann, head of the team's powertrain department.
"There was a high-frequency AC voltage between these contact points, the cause of which has been traced back to the KERS control unit and a sporadic capacitive coupling from the high-voltage network to the 12-volt network.
"The voltage ran through the wiring of the 12-volt network to the steering wheel and through the carbon chassis back to the control unit."
"However, the energy is sufficient to cause an extremely painful reaction.
"The driver was insulated against the car by his racing overalls and gloves and therefore not in any danger."
He added that the investigation had taken almost a month because, having been caused by a "sporadic error", the problem was hard to replicate.
"The capacitive coupling effect only occurs under certain conditions," he explained.
"Without the option of driving the KERS test car used in Jerez again, we had to reconstruct these conditions.
"We also had to develop a model to be installed between the steering wheel and sidepod which replicated the characteristics of the human body as an electric transfer element."
As a result of its investigation BMW has discovered other measures that could avert potential safety problems with the KERS devices - findings which it will share with all F1 teams at the next meeting of the Technical Working Group.
"In addition to the measures required to tackle the issue at hand, the extremely far-reaching analysis we conducted also gave rise to other recommendations which are of great value for the development of electric KERS systems," said Duesmann.
"Among the measures arrived at are changes in the design of the control unit to avoid capacitive coupling effects, extended monitoring functions for high frequencies and a conductive connection of the chassis components to avoid any electric potential.
"We have already handed over this safety analysis, complete with measures and recommendations, to the FIA, and will also make our findings available to the other teams at the next meeting of the Technical Working Group."
Duesmann said BMW will resume track testing of KERS-equipped cars once all the necessary safety modifications have been implemented.
"We expect this to be the case in the autumn," he said.
Source: ITV.com/f1
Log in to comment