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在震前地声与电磁波的观测研究中,为节省经费及外汇,常用普通盒式磁带录音机代替昂贵的磁带记录器担任信息记录.盒式录音机无论是高、中档机还是普及型机,也不论是单声道的还是立体声的,均采用世界统一走带速度,即4.75厘米/秒(1(1/8)时/秒),如能增加一个带速为2.375厘米/秒(15/16时/秒)的低速档.则每盘磁带的录放时间可增加一倍.此外,可用常速,对低速录制的磁带进行快速转录,使复制时间缩短一半,这不仅可以节省磁带,而且给使用带来很多方便.下面介绍一种录音机的减速装置.工作原理盒式录音机的走带驱动电机均采用永磁直流电动机.我们知道,永磁直流电动机的转矩M取决于供给电枢的电流
In the study of acoustical and electromagnetic waves before the earthquake, in order to save money and foreign exchange, it is common to use ordinary cassette tape recorders instead of expensive tape recorders for information recording. The cassette recorders, whether high, midrange or pervasive, Is mono or stereo, are using the world’s unified transport speed, which is 4.75 cm / s (1 (1/8) h / s), such as adding a belt speed of 2.375 cm / s (15/16 / S), then the recording and playback time of each tape can be doubled.Furthermore, the ability to quickly record low-speed recorded tapes at constant speed and reduce the duplication time by half can not only save the tape, To a lot of convenience. Here’s a decelerator recorder. Working principle Cassette tape drive motors are used permanent magnet DC motor.We know that the permanent magnet DC motor torque M depends on the current supply to the armature