screen printing > General Screen Printing

quick electrical question

(1/2) > >>

Sbrem:
On our old trusty MHM Synchro S, we are replacing a transformer which sends 24vdc to the display. The old unit and the replacement looks world's apart, but we have it figured out, mostly. On the original, the + and - output terminals have 2 wires each going to the display. The folks at SPSI told us to use an 8 amp fuse on the positive side. On the old unit, the 2 positive wires were joined together, on the positive terminal, same with the negative. On the replacement unit, there are 2 terminals for positive and 2 terminals for negative. Finally, the actual question, do we need to fuse both positives? Or can we join them together with a single fuse?
Second question, which I should know, but I'm not 100% sure; there are 3 lines going into the old transformer input, the ground, and a black, and blue. I think black is the N and the blue is the L, but I'd love someone who know better to confirm it. For some reason, we aren't getting the replies we need from folks we're dealing with, I'm sure they're busy. Thanks, all.

Steve

On second thought, I think that fuse goes on input to the transformer, the little red box is a fuse holder

Sbrem:
first picture, the new unit

Sbrem:
2nd picture, old unit

3Deep:
Don't have any answers for you, but I know what your going through, had to replace a panel in our flash unit which cause us to reset the whole press main head what a pain.  Would really be nice to replace the part with the same part that came off plug and play, but as the press gets older the more unlikely are you going to find the exact part.

ebscreen:
Hi Steve. We have sameish press, (this particular electrical portion has a few revisions...)
if you need pics of anything let me know.

>>On the old unit, the 2 positive wires were joined together, on the positive terminal, same with the negative.
>>On the replacement unit, there are 2 terminals for positive and 2 terminals for negative.

You can use both terminals or one, doesn't matter, they are physically bonded.


>>Finally, the actual question, do we need to fuse both positives?
Current for both needs to pass through an appropriate fuse. If they were originally connected to the output of one 8 amp
fuse that is what I would do. It's a little odd (you typically want one fuse per circuit) but don't rock the boat.

MeanWell are pretty decent power supplies and usually have over-current protection as well. They'll shutoff automatically until
power cycled. Also, they are adjustable within a small range. That white potentiometer to the right is the adjustment, and it's
probably not a bad idea to check the output (under load/fully connected) at 24v with a multimeter between the V+ and V- terminals.


>>I think black is the N and the blue is the L
Likely correct, you can carefully check with a multimeter between black/blue and ground. Line will have voltage.
It's not particularly important in this regard though, the power supply will operate either way.




Lastly, how did you condemn the transformer/power supply?
Transformers themselves are pretty low on the electrical component failure chart.
The rest of the smoothing circuitry can be suspect though (those big caps in first pic)


On our sameish press we had the craziest gremlin involving the same component.
Machine would be operating fine and then contactor would start buzzing/random lights flickering.
Changed contactor didn't help. Checked incoming voltage and it was fluctuating wildly while operating, started tracing back
to panel. Before tearing conduit down I watched closely in the machine panel and noticed arcing.
Hot wire into 24v transformer had come loose (or had always been?) and was wreaking havoc.
Just a data point.

Lastly lastly S-Type manual is attached. MHM was really good about including schematiks.

Navigation

[0] Message Index

[#] Next page