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A water pump provides
coolant circulation through the power inverter and AC motor. As a heat exchanger vehicle
stock radiator can be used, but so much de-heating capacity is not required - near 90%
efficient AC drive system generates far less heat than 23%...27% efficient internal
combustion engine. For the same reason it is hopeless to use cooling water to heat the
cabin or batteries in the EV - the water is barely warm to the touch when the system runs.
One type of automotive grade water pump is available - 12 VDC, magnetic drive type, which means the impeller is contained in totally enclosed chamber with no shaft link to the motor so there is no possibility for leak. Bosch pump uses BLDC motor. Magnetized impeller is driven by magnetic field of another cylindrical magnet attached to the motor shaft. Both magnets are separated by plastic wall. Rated for continuous duty to pump water or the standard cooling solution (ethylene glycol and water mixture) up to 100 °C. Despite small physical size (Bosch pump is about size of a fist) the water flow it puts out is impressive and certainly move enough water to keep both inverter and motor drawing maximum power well within their temp. spec (provided radiator area is large enough). Water inlet and outlet fittings are 19 mm (3/4") for clear plastic tube or rubber hose connection. Made in Germany by Robert Bosch AG Corp. One year warranty. |
