Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems.

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Default Incomprehensible industrial schematic

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 passives.

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 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!

Thanks,
--
DaveC

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Default Incomprehensible industrial schematic

On Mon, 8 Dec 2008 23:22:17 -0800, DaveC wrote:

:This is a partial wiring diagram for an early 80's (West) German guillotine
aper 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 passives.
:
: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 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!
:
:Thanks,

Not even LM Ericsson x-bar schematics use such nondescript symbols, and their
symbols took some getting used to back in the 60's.

I'm afraid you are going to have to trace out the wiring while comparing it with
the schematic and that way you should be able to work out what each of the
nondescript items with the triangle symbols are. My guess is that they indicate
some sort of active semiconductor function block. There may be additional
schematics detailing what is in each block but if that were so then one would
expect to see some identifier number written inside each block but I don't see
this information either.

Good luck!
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Default Incomprehensible industrial schematic

DaveC wrote in message
obal.net...
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 passives.

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

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!

Thanks,
--
DaveC

This is an invalid return address
Please reply in the news group



repost to
de.sci.electronics
perhaps


--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/



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Default Incomprehensible industrial schematic

DaveC wrote:
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 passives.

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 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!

Thanks,


Try de.sci.ing.elektrotechnik perhaps

--
Jeff



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Default Incomprehensible industrial schematic


"DaveC" skrev i meddelelsen
obal.net...

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 passives.


Hmm. The box-with-a-triangle symbol looks like a logic gate to me.


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
use a
voltage derived directly from the 3-phase input to drive the
electromagnetic
clutch. Why use a switched voltage, I cannot understand.


Probably some safety loop required/mandatory wherever the machine was first
sold; the cutter will not operate when certain hatches wired with door
swithces are open e.t.c. Machines are often customised - even the same
machine from the same manufacturer can be somewhat different. If they are
picked up used or at bancrupcy auctions - as I like to do - it will show.


Is the triangle within a square symbol some sort of odd representation of
a
transistor? And the "arrow thing" that feeds them? Ideas?


I really think they are logic gates, it looks a bit like the way Siemens
would draw them. The box-with-triangle-at-top looks like some kind of limit
switch, probably pneumatic.

The individual gates may well be implemented with a bunch of discrete
components, including transistors!

Guess you have to dig out the ole meter and walk the wiring in the terminal
blocks* - ohh those were the times ;-)



*Often the wiring is wrong too - yet the unit still worked thousands of
hours with the fault. This should not worry you unduly. Muahahahaha ;-)


Help!

Thanks,
--
DaveC

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Default Incomprehensible industrial schematic

In the US, a triangle is usually a symbol for a gain stage -- most-often an
op amp. But it can also be a driver, which is likely what the triangles you
think might be transistors are.

But... I've never seen a schematic like this. Whoever drew it seems to be
using one symbol to represent different devices.

I would trace everything out, starting from the side of the transformer on
the "flat" side of the triangle. As you find parts that match the schematic
symbols, you might be able to start unscrambling the symbols' meanings.


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Default Incomprehensible industrial schematic

repost to
de.sci.electronics


Thanks.
--
DaveC

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Default Incomprehensible industrial schematic

DaveC wrote:
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 passives.

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?


Looks like the transformer must run switch-mode. The clutch is 42V while
the rest of the circuit is 24V - may be why a transformer is used.

I don't see any connection that can get to ground on the transformer
primary. Everything looks like it goes to 24+. Could be the
"Transistors?" mount on, and connect to, a grounded surface - not shown.
(That would give the "Transistors?" 4 leads.). "??" is the switch-mode
drive? Would think it also would need a ground - maybe not shown?

Where parts are about all identified it seems strange the blocks with
triangles and "??" have no identification at all.


I can say from experience that other machines of this same manufacturer use a
voltage derived directly from the 3-phase input to drive the electromagnetic
clutch. Why use a switched voltage, I cannot understand.


The manufacturer may want all of the control to be low voltage?


Is the triangle within a square symbol some sort of odd representation of a
transistor? And the "arrow thing" that feeds them? Ideas?


My dipsiht news provider apparently no longer allows crossposting. Not
knowing which newsgroup the OP watches this is posted on all 3
newsgroups. Sorry.
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Default Incomprehensible industrial schematic

On Mon, 8 Dec 2008 23:22:17 -0800, DaveC put
finger to keyboard and composed:

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 passives.

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?


Maybe this particular clutch requires a higher frequency than 50Hz or
60Hz ???

I can say from experience that other machines of this same manufacturer 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?


I'd say it's probably an NPN transistor (plus associated components
?). I suspect that the rectangular block immediately above the two
chopper transistors (?) is probably an oscillator or multivibrator.

Having said that, I can't follow the current path. It appears to flow
into the transformer's centre tap and then out via either end of the
primary winding. It must then flow through the "transistors" into the
"oscillator" because the side paths are blocked by reverse biased
diodes. But the remaining terminal for the oscillator is also blocked
by diodes ...

It seems to me that your circuit is some kind of hybrid block diagram.

Help!

Thanks,



- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.
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Default Incomprehensible industrial schematic


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

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

Help!

Thanks,
--
DaveC

This is an invalid return address
Please reply in the news group


I believe you will find "the arrow thing" will be an astable multivibrator.

I suspect the following stage are time delay relays modules. Note they are
controlled by 24 VDC yet they are controlling AC... after all, you need AC
to run a transformer.






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Default Incomprehensible industrial schematic

On Wed, 10 Dec 2008 11:41:45 +1100, Franc Zabkar
put finger to keyboard and composed:

Having said that, I can't follow the current path. It appears to flow
into the transformer's centre tap and then out via either end of the
primary winding. It must then flow through the "transistors" into the
"oscillator" because the side paths are blocked by reverse biased
diodes. But the remaining terminal for the oscillator is also blocked
by diodes ...


Sorry, I didn't read bud's post properly. It appears that he has
already come to the same conclusion.

- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.
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Default Incomprehensible industrial schematic

On Tue, 9 Dec 2008 08:24:37 -0800, DaveC wrote:

: repost to
: de.sci.electronics
:
:Thanks.


Your query seems to have the contibutors on de.sci.ing.elektrotechnik just as
baffled as the rest of us here Dave....
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Default Incomprehensible industrial schematic

The transformer feeds a block with a triangle symbol, so my hypothesis
is that this represents "rectifier" and it's a full-wave bridge,
especially as it says 42V= (42VDC) underneath. The block on the left
with three inputs at the top could be a three-phase rectifier, and the
small blocks with three terminals could be silicon controlled
rectifiers. Your mystery block must be something which flips into one
of two positions.

Dave W
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Default Incomprehensible industrial schematic



DaveC wrote:

This is a partial wiring diagram for an early 80's (West) German guillotine
paper cutter:


That's a perfectly normal Euro standard symbol for a transformer.

The thing with an arrow it feeds is obviously a bridge rectifier which makes me
wonder if the arrow symbol thingies with 3 connections might be SCRs.

But the rest is extremely odd.

The ?? might be a panel mounted SPCO switch.

And yes, the clutch is in black because it's inductive.

Graham

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Default Incomprehensible industrial schematic

DaveC wrote:
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 passives.

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 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?


The rectangle with double-headed arrow *might* be a center-tapped
inductor/choke. If the two items underneath it that you marked
'transistors?' are actually SCR's, then a center-tapped inductor could be
used to commutate them. When one fires, the sudden rush of current through
that half of the inductor produces enough induction to stop/reverse the
current through the other side and commutate (shut-off) the other SCR. In a
slightly different form this sort of circuit used to be used in power
inverters.

So the two SCR's would pulse each end of the center-tapped primary of the
transformer. But I'm not sure of the rest since it looks like +24V is
feeding the choke/SCR and the center-tap of the transformer primary is also
+24V. Where does match-mark 'A' go off to?

daestrom



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Default Incomprehensible industrial schematic

Where does match-mark 'A' go off to?

To the coil of yet another logic relay (d71). It energizes the relay coil.
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