D
Close but no cigar..... i think?Я понятия не имею!
50 plus years of a early hard mould plastic plunger eventually wears it away, its possible to probably do a makeshift repair but as its fuctio is braking related its best to replace for sake of £50 ....Electrically still sound.Nice bit of traditional Soviet technology there Dark, what actually failed on it? Most of their industrial stuff seems to go on almost for ever.
Signal amp
Bingo! Not wild guesses at all... It's a magnetic amplifier. The core is magnetised to half its saturation level by a winding carrying DC. The speed pot sends DC through another winding, the feedback circuit sends DC through a third with opposite polarity, so the steady flux level represents the difference between the two. The degree of saturation controls the power transfer from the AC energising circuit to the rectifier, which produces a DC output to excite the servo-generator, which in turn controls the main generator field and hence the output fed to the spindle motor. 7 hp of stabilised speed control without a thyristor or transistor in sight.
Lucien
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DW, ever come across Square D pneumatic timers? Depending how you put them together they were either delay on or delay off.