| 摘要 |
<p>PURPOSE:To avoid the generation of excessive braking torque due to the increased regenerative current by a method wherein the field current flowing in the field winding is restrained when the armature current reaches the specified level. CONSTITUTION:When the output voltage Vout of the regenerative current detection circuit 15 inputting the output signal Vin of the current transformer 14 is zero, the deviation signal between the field current directive signal and the field current from the field current directive circuits 8 or 9 is input into the chopper 4 after the specifid signal processing by means of the amplifier 11 and the phase shifter 12. When the regenerative current exceeds the specified value, the output voltage Vout is output from the regenerative current detection circuit 15. The regenerative current is reduced by the decrease of the field current, as the field current directive signal is reduced by the decrease of the said output voltage Vout. Through these procedures, the excessive braking torque is prevented from generating to avoid the resultant shock.</p> |
