Diode on vibe pump to quiet it down?

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JavaJive
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Joined: 12 years ago

#1: Post by JavaJive »

Hi...

Many years ago, a very experienced tech from Italy told me that
"putting a diode on a vibrating pump" will quiet it significantly.
He said he did that on my machine during a warranty repair.

Does anybody know if there's any truth to this?
If so, what does "put a diode ON the pump" mean?
IE: where.... across the terminals?

How would this work?

Thanks in advance....
I'd like to put this to rest in my mind once and for all...

Greg

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allon
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Joined: 13 years ago

#2: Post by allon »

You take a 3A rectifier diode (or whatever you can find that'll take the current) and put it in series with one of the leads to the pump.

See wiring diagram on bottom right of page 1:
http://www.fluidotech.it/Contents/Docum ... series.pdf

Fluid-o-tech pumps require a diode.
It is possible that a diode is hidden inside the connector for the pump.

If you mess up and add a diode when there is already a diode in the circuit, then either it will be the same polarity as the other diode and nothing bad happens (nothing extra - you still get the benefit, if a diode is required, but the second diode will do nothing additional) or it will be the opposite polarity, in which case all current to the pump will be blocked and the pump won't run.

I'm not sure if putting a diode on an ulka pump will have any benefits or detriments.
LMWDP #331

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yakster
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#3: Post by yakster »

You lose a bit of voltage, .3 - .7 V typically, with each diode in the conducted direction so adding a second diode would drop the voltage to the pump some more. How that would affect the pump, it would depend on the voltage rating of the pump.

I've seen external USB battery sources use an LED (light emitting diode) with 4 x 1.5 V batteries to drop the voltage (and indicate the battery is on) from 6 V to 5.3 V, close enough to 5 V to do the job.
-Chris

LMWDP # 272

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allon
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#4: Post by allon »

I wasn't gonna get into the forward voltage drop - pretty negligible and probably a non-issue, but yeah, you don't want to keep stacking them...

A fair point.
LMWDP #331

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erics
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#5: Post by erics »

The Ulka pump already has a built-in diode - item 3 below:



This was an educational autopsy of a dead coil.
Skål,

Eric S.
http://users.rcn.com/erics/
E-mail: erics at rcn dot com

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JavaJive (original poster)
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Joined: 12 years ago

#6: Post by JavaJive (original poster) »

Wow!
What an incredibly thorough set of replies!
I don't think there's much to say on the topic.
Thanks much guys!

At least now I know where to look to see if there is one.
Seems doubtful though, given whats been said above and the fact that there's
already one on the pump in question.
That tech did say he installed one FWIW.. and it DID seem noticably quieter
when I got it back.... hence my curiosity.
Of course that could be due to other factors I suppose.....

I wonder if a slight voltage drop.. say .5V could be desirable in some cases..
like to function as a sort of OPV on machines with non-adjustable OPVs...
Perhaps even a tad quieter?

What is it about a diode that makes it quieter?
How does that work?

Thanks so much again..
Greg