BMW Sauber F1 Team - Interview on KERS
21-08-2008 Press Release
Interview with Markus Duesmann, Head of Powertrain BMW Sauber F1 Team
Munich/Hinwil, 21.8.2008. The BMW Sauber F1 Team have now concluded
their investigations into the KERS incident at Jerez in late July.
Markus Duesmann, Head of Powertrain, gives us more details.
What exactly happened in Jerez?
Markus Duesmann, Head of Powertrain: “The mechanic suffered an
electric shock after touching the sidepod and steering wheel of the
car. 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.”
Note on capacitive coupling: this refers to an inadvertent
transfer of electric voltage between two transfer media by inductive or
capacitive coupling.
Was there a serious danger to the mechanic and the driver?
Duesmann: “No, as only a small amount of energy can be transferred
through this capacitive coupling effect. 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.”
Why did the investigation take so long?
Duesmann: “It was not possible initially to reproduce the
capacitive coupling effect in the car, as the problem was caused by a
sporadic error in the control unit. Due to the extremely high frequency
of the voltage in the steering wheel, the safety mechanisms and data
recordings did not pick up on the error. In the absence of data, all
the theoretical possibilities had to be systematically investigated and
analysed in tests. Furthermore, the capacitive coupling effect only
occurs under certain conditions. 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.”
What measures are now being taken to solve the problem?
Duesmann: “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. 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.”
What will happen with these findings now?
Duesmann: “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.”
When will the next track test for KERS take place?
Duesmann: “We will resume the testing programme once all the
necessary amendments to the safety concept have been implemented. We
expect this to be the case in the autumn.”
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