| 摘要 |
PURPOSE:To discriminate the position and the degree of defect of insulation to the ground of a DC motor without disconnecting the DC motor from a power source, by connecting one end of a detecting resistance to a contact element or a detecting lead connected to a commutator segment of the DC motor and extracting a voltage across both ends of the detecting resistance as a detection signal, and calculating values of insulation to the ground of the power source side and the armature side. CONSTITUTION:One end of a detecting resistance Rd is connected to a contact 18A, which is brought into contact with one rectifier segment of a DC motor 14 freely slidably, through a lead wire 52, and the other end is grounded. The input of an amplifier 54 is connected to the contact-side end of the detecting resistance Rd so that a voltage Vd across both ends of the detecting resistance Rd is detected and amplified, and the output of the amplifier 54 is inputted to a signal processing device 56. A recording meter and printer 58 is connected to the signal processing device 56. A P-side bus insulation leak resistance Rp, N-side bus insulation leak resistance Rn, and an armature internal grounding resistance rg are set for the DC motor 14 to which the diagnostic circuit of insulation to the ground is connected in this manner, and the Kirchhoff's second law is applied to each closed circuit, and the circuit is diagnosed in accordance with the waveform of the detected voltage Vd. |
