| 摘要 |
PURPOSE:To detect overheat state at all times and to realize effective cooling by providing means for detecting the voltage of a resistor, means for detecting overheat based on thus detected voltage, and a fan being driven by an overheat signal. CONSTITUTION:When a vehicle is traveling, a voltage sensor 56 detects the voltage Er across a resistor 35 continuously and thus detected voltage Er is fed to an overheat detecting circuit 46 where it is compared with a set voltage EH. Under a condition where an electric brake is repeated with a high brake torque TB, a battery 33 is sufficiently charged and a semiconductor switch circuit 34 feeds much current to the resistor 35 which thereby consumes power positively thus ensuring a high brake torque TB. When the voltage Er exceeds the set voltage EH due to a high current, an overheat signal is fed to a motor 12 which then rotary drives a fan 13 thus cooling the resistor 35. |
