BMW I01 Product Information page 28

I01￿High-voltage￿Components
3.￿Electric￿Motor
The￿electrical￿machine￿is￿designed￿for￿a￿large￿temperature￿range.￿The￿coolant￿can￿reach￿a￿temperature
of￿up￿to￿70 °C￿at￿the￿input￿(supply).￿And￿although￿the￿electrical￿machine￿demonstrates￿less￿losses
during￿energy￿conversion￿than￿a￿combustion￿engine,￿its￿housing￿can￿absorb￿a￿temperature￿of￿up￿to
100 °C.
Danger￿of￿injury:￿The￿housing￿of￿the￿electrical￿machine￿can￿absorb￿temperatures￿of￿up￿to￿100 °C
during￿operation.￿A￿sufficiently￿long￿time￿must￿be￿waited￿for￿cooling￿if￿work￿is￿to￿be￿performed,￿for
example￿the￿removal￿of￿the￿drive￿unit.
Sensors
In￿order￿to￿avoid￿damage￿to￿the￿components￿due￿to￿the￿high￿temperature,￿there￿are￿two￿temperature
sensors￿in￿the￿electrical￿machine￿of￿the￿I01.￿Both￿temperature￿sensors￿are￿located￿in￿the￿coils
of￿the￿stator.￿The￿temperature￿of￿the￿rotor￿is￿not￿measured￿directly,￿but￿can￿be￿determined￿from
the￿measured￿values￿of￿the￿temperature￿sensors￿in￿the￿stator.￿The￿two￿temperature￿sensors￿are
temperature-dependent￿resistors￿of￿type￿NTC.￿Their￿signals￿are￿read￿in￿and￿evaluated￿analogically￿by
the￿electrical￿machine￿electronics.
So￿that￿the￿voltages￿for￿the￿coils￿in￿the￿stator￿can￿be￿correctly￿calculated￿and￿generated￿by￿the
electrical￿machine￿electronics￿in￿terms￿of￿amplitude￿and￿phase￿layer,￿the￿precise￿angle￿setting￿of￿the
rotor￿must￿be￿known.￿This￿is￿why￿there￿is￿a￿rotor￿position￿sensor￿at￿the￿end￿of￿the￿drive￿shaft,￿which￿is
turned￿away￿from￿the￿transmission.
Electrical￿connections￿of￿the￿electrical￿machine
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