This is a partial wiring diagram for an early 80's (West) German guillotine paper cutter:
The goal of this circuit is to energize an electromagnetic clutch coil (m27) that takes rotational energy from a flywheel to do a task (bring down the knife blade). This circuit is currently not working.
This machine has no ICs. There are some monolithic rectifier bridges and discrete transistors (the common symbol for which I cannot find *one* in the diagram), and plenty of passive components.
The transformer (m) primary center tap is connected to 24vdc. Do I interpret this correctly that the primary is run by a switched dc voltage? (This on a machine that runs on 3-phase 245vac.) Why?
I can say from experience that other machines of this same manufacturer (Polar) use a voltage derived directly from the 3-phase input to drive the electromagnetic clutch. Why use a switched voltage, I cannot understand.
Is the triangle within a square symbol some sort of odd representation of a transistor? And the "arrow thing" that feeds them? Ideas?
Help!
danke,