Strange schematic [Englisch]

09/12/2008 - 16:57 von DaveC | Report spam
This is a partial wiring diagram for an early 80's (West) German guillotine
paper cutter:

<http://freefilehosting.net/show/42l0i>

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,
DaveC
me@bogusdomain.net
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#1 j
09/12/2008 - 17:58 | Warnen spam
DaveC wrote:

Is the triangle within a square symbol some sort of odd
representation of a transistor?



It's the block diagram symbol for an amplifier. So presumably, your
transistors somehow go there.

And the "arrow thing" that feeds them? Ideas?



No idea on that one. Some kind of "alternating switch" or such, the
entire circuit looks like a voltage inverter, so maybe it is
switch-driven by some kind of mechanical feedback to keep it in synch?
cheers, J"org .-.-. --... ...-- -.. . DL8DTL

http://www.sax.de/~joerg/ NIC: JW11-RIPE
Never trust an operating system you don't have sources for. ;-)

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