| 摘要 |
PROBLEM TO BE SOLVED: To reduce the cost of parts for a space heater, and simplify a circuit structure by forming a braking resistor into a heater for keeping an inverter warm while it is inoperative. SOLUTION: An inverter 1a is provided with a series circuit consisting of a breaking resistor 21 for consuming regenerative power outputted by an electric motor at the time of regenerative braking, and a transistor 7 (switching element), and a braking part 18a (switching control means) which controls an inverter 10 and the transistor 7 by PWM switching and on/off controls contactors 4, 15. A rectifier 2, the inverter 10, a reactor 3, a contact 4, a capacitor 9, a charging resistor 5, the transistor 7, and a control part 8a are stored into a casing 12a. The casing 12a is kept warm by a braking resistor 21 serving as a space heater. |
