| 摘要 |
<p>PURPOSE:To enable arc-extinguishing of an SCR free from the effect of the inductance of resistances by arranging a diode parallel with a resistance of a commutation closed circuit comprising the SCR and the resistance when using a chopper containing a generation brake control. CONSTITUTION:A closed circuit is made up of a DC motor 1, a main SCR2 and a reactor 6. A series circuit comprising an SCR3 and a resistance 8 is connected in parallel to a series circuit of the SCR2 and the reactor 6. In addition, a diode 12 is connected in parallel to the resistance 8 in such a manner as to be reverse in the characteristic to the SCR3. This eliminates effects of inductance of the resistance 8 enabling quick arc-extinguishing of the SCR3. Besides, the arc-extinguishing of the SCR3 can be done without increased the capacity of a condenser 7 for commutation and without use of the resistance 8 smaller in the inductance.</p> |
