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SC型间歇正压呼吸机,采用可控硅直流无级调速电路(见附图),主电路由整流管、可控硅管、直流伺服电机及控制电路组成。R_(23)和C_4与SCR并联后限制换向过电压,C_3和R_(22)为过电压保护阻容吸收装置,D_(13)是续流二极管。它的定子励磁线圈接在主电路可控硅和D_(14)～D_(17)整流管之间,以保证励磁线圈先于电枢电路之前接通电源,防止电机失励造成事故。控制电路采用由BG_1、BG_2、BG_3组成
SC type intermittent positive pressure breathing machine, using SCR DC stepless speed regulation circuit (see photo), the main circuit from the rectifier, SCR, DC servo motor and control circuit. R_ (23) and C_4 limit the commutation overvoltage in parallel with SCR. C_3 and R_ (22) are overvoltage protection RC reactors, and D_ (13) are freewheeling diodes. Its stator excitation coil connected between the main circuit thyristor and D_ (14) ~ D_ (17) rectifier to ensure that the excitation coil before the armature circuit connected to the power supply, to prevent motor failure caused by accident. The control circuit consists of BG_1, BG_2, BG_3