| 摘要 |
PURPOSE:To prevent the thermal breaddown of a transistor by adding a temperature limiting loop for reducing the supplying current to a motor coil when the temperature of the transistor is detected and is the prescribed value or higher. CONSTITUTION:Drive transistors 5-7 are connected to a plurality of moter coils 2-4, a signal from a position detector 8 of a rotor 1 and a signal from a current detector 4 are applied to a distributor 9 to control a current corresponding to a command signal from a command signal generator 10 having a speed detector 23, and to control the voltage by a voltage converter 13 and an operation detector 12. A temperature detector 11 containing a temperature detecting transistor 66 disposed intimately with drive transistors 5-7 is provided, the output of the detector 10 is corrected by the output, thereby controlling the supplied current to the coils 2-4. Accordingly, the temperature rise of the transistors 5- 7 are suppressed to improve the reliability. |
