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Power supply for diaphragm pump

Discussion in 'Electronic Projects Design/Ideas/Reviews' started by ADWSystems, Aug 24, 2017.

  1. ADWSystems

    ADWSystems Member

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  2. GromTag

    GromTag Active Member

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    A potential would be the 1K adjuster/ trimmer setting next to the positive out from the power supply itself. What would be the voltage out of the power supply when powered with no load attached?
     
  3. GromTag

    GromTag Active Member

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    Just out of concept,
    On the 12V 20A model in the listing showed a switch on the power supply side, the 120V outlet or the 220V outlet.

    If the supply is switched to 220 and plugged into an 120 avg volt outlet, the output can state 12V DC on the output but not have any realistic current available under use IF that happens to be the case.

    If the output states close to or at 12V and the trimmer is calibrated to provide this with the input switch correctly set and the power supply still defunct, then the supply would be more towards problematic.

    ------------------------
    : This is not likely :
    Other thoughts are, if the supply would be showing close to 12V on its output and the input switch at the correct setting, for example a 120V outlet and input switch set to 120V, if the output would be loaded down by a resistor, 100R for example, or a 12V DC bulb, and the output drops a considerable amount then very unlikely but possible, the input voltage switch could be backwards, had a few DELL Lite on PSU's back prior to 2004 wired in incorrectly on some replacement for faulty cap models. (thrown together).

    If that happens try the 220V input switch setting on the supply with an 120V only outlet and test again briefly.
    ------------------------

    (avoiding the pump use for the testing for the possibility of damage just in case the supply IS problematic)

    :Edit: ... Or the sticker does not properly represent the model accurately.
     
  4. dave

    Dave New Member

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  5. Pommie

    Pommie Well-Known Member Most Helpful Member

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    I've used these type of supplies without any problem. The regulation isn't great as they're meant to power LEDs but for your application they should be fine.

    Mike.
     
  6. ADWSystems

    ADWSystems Member

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    That is both what I was afraid someone would say and what I expected someone to say.
    For powering a pump, regulation is not really necessary. I just need power. I can only test the power supply to 2.4A. I don't have a small enough high wattage resistor to run the power supply harder. The next higher wattage item is the pump. When I connect the pump, as soon as I flip the switch the pump turns a few degrees and stops and the power supply shuts down. Then the supply recovers and shuts down. Then the power supply recovers and shuts down. In rush current problem? What can I do to get this power supply to drive the pump? Bank of capacitors? How big (how many uF)?
     
    Last edited: Aug 25, 2017
  7. jpanhalt

    jpanhalt Well-Known Member Most Helpful Member

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    I have tested a similar supplies and didn't have "properly" rated resistors. For testing purposes only, I put the resistors in a bucket of water to increase their wattage. Another option is use 12-volt lamps, as in automotive head lamps.

    In your case, are you sure the pump is OK? Test it off an automotive battery. If that works, then it seems the supply you have is simply inadequate.

    John
     
  8. GromTag

    GromTag Active Member

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    On edge of the supplies ability. A resistor inline with the pump to drop some current and then gauge the results by observation. The pumps supply total is 20A correct? usually this would mean the absolute limit, however a thought of what if the pump allows as with any direct or as close to drive as much current that an supply can feed.

    Also the pump if not realistically any problem, may have a continuous draw that exceeds the supplies limit at each start up attempt.

    A 100uF cap would show some kind of difference. The supply would be fine driving that up being the output switching stage is the weakest part of the drive as some start up slowly when main input power applied. The more thought into the further things can get sort of why was this not mentioned earlier... I just thought of it. Otherwise if it were an immediate start of the supply the 100uF would see near a few hundred amps at start as well as any load.
     
  9. GromTag

    GromTag Active Member

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    The supply at startup may not be able to get over the hill.. Or mountain.
     
  10. ADWSystems

    ADWSystems Member

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    Pssst. See post #1. When tested from an automotive car battery, the no load running current is just over 3 amps.

    100uF seems small for a pump that draws 3A no load, 6A typical, and 15A maximum (per the "datasheet").
     
  11. Pommie

    Pommie Well-Known Member Most Helpful Member

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    As suggested above a series resistor should limit the inrush (stall) current. Start with something like 0.5Ω and see how that works - you might be able to tweek the output voltage to around 13V to make the run voltage correct.

    Mike.
     
  12. GromTag

    GromTag Active Member

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    Forgot a zero in there somewhere. From a projects box here, a 360 actuator motor operating at 12V 6A nominal shows some start up drop with an 3300uF (3.3mF) Ruby - a y goes there not an i) cap with a supply that can only offer 4 Amp, tho it's a transformer based supply. Close figures based on supply recovery and ability to sustain the pumps switch in if it's to be externally switched on and off with the supply operating and stable.

    :Edit: a Denso metal geared 360 type that can break fingers... what a warning sticker left on it.
     
    Last edited: Aug 25, 2017
  13. ADWSystems

    ADWSystems Member

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    I have the adjuster dialed all the way up (12.75V, it goes further down than up :(). I'm not sure I have a 0.5 ohm resistor more than 1/4W. What would work for testing? If successful, How large of a 0.5 ohm resistor for the final solution? P=I^2*R=15^2*0.5=112.5W (min)?

    If successful with the current limiting, I could also use relays to switch the startup relay out of the circuit. I'll figure out how to cross that river if and when I get to it.

    GromTag, what are you trying to say? The only part I can follow is the use of a 4A transformer based power supply.
     
    Last edited: Aug 25, 2017
  14. GromTag

    GromTag Active Member

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    Been on night watch here, burnt out I am :oops:

    100uF capacitor was not correct, meant to say as a exampled 1000uF starter cap instead. The 4A transformer supply I mentioned was an example of a power supply for an 360 geared motor that I have that rates nominal 6 Amps, the start up was rated at a best 8Amp start up.

    The Capacitor on my exampled supply is stated 3300 uF at 50V, thus with this I mentioned the motor starting and with only a small noticeable drop in rotation (no load) The cap quite well handled the start up for the 4Amp transformer supply to sustain the motor when switched on with the transformer plugged in and operating.

    So. a 2200uF to 3300uF capacitor should produce some improved results. in the range of 100 milliohm to 2 Ohms ESR should work adequate, would not have to be low ESR unless the cap is expected to stall the brunt of an unexpected heavy load on the pump, like a stall/jam.
     
  15. ADWSystems

    ADWSystems Member

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    I tried a single 4700uF capacitor and then pair of 4700uF capacitors in parallel. No luck. The lowest high wattage resistor I could make is 5 ohms. I put that in series with the pump, alone, with the 4700uF cap, and the pair of 4700uF caps. No luck on any of the 6 combinations. I do not know what it will take to start and run this pump from a power supply.
     
  16. Pommie

    Pommie Well-Known Member Most Helpful Member

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    There is something very wrong with your power supply. A 5Ω resistor alone would only draw a little over 2A!! I'm assuming you had the resistor in series with the pump and any capacitors in parallel,

    Mike.
     
  17. ADWSystems

    ADWSystems Member

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    PS -> Cap -> Resistor -> Switch -> Pump -> PS

    I have the switch down stream of the capacitors so they will charge. The pump has QC terminals, so it is easy to hook the pump to the switch.

    After reading the last post, I realize I need to clarify what didn't work. (my bad, sorry).

    With and without the capacitor(s) only (no current limiting resistor), the 'system acted the same. The pump started then stalled as the power supply dropped out (LED off, voltage dropped to 0V).

    When the 5 ohm resistor is added (with or without the capacitors, the power supply stays alive, but the pump does not react at all. The pump doesn't start, bump, hiccup. Nothing. The voltage drop across the 5 ohm resistor is about 1V (which gives about 200mA).
     
  18. GromTag

    GromTag Active Member

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    Inductive vs non.

    A 55R motor. If it is a 12V pump. Correct polarity under drive from the supply is not being sustained from the supply when driving something inductive. A car battery can supply the current greater than a switching supply in more than many cases, inductive or not.

    Been using some supplies here and I found the results you have mentioned repeatedly with "isolated" output type supplies to re redundant with these similar issues. the supply powers on, then shuts down over and over.

    The testing result of even using a diode and an exponent capacitor to allow the isolated supply to switch on a fan that was switching the CUI on and off. So by charge pulsing the diode driven capacitor on CUI supply start up attempts ( the fan used in test, TA450DC Nidec betaV at 1.40 Amp draw) with the just acquired CUI DC/DC, the CUI PYB15-Q48-S12-U has a limit of 1.2 Amp. The fan still caused the CUI to switch on/off repeatedly.

    True the Amp rating is being exceeded, tho not by far, it also does the same when I connect a 12V Lithium intelligent balance chip controlled IC battery, the CUI supply starts up then shuts down over and over even with the battery not fully discharged, the battery drained to 10V level to gain info if this CUI could charge the battery at any effort that flopped in the charging attempt. The battery has built in current limit charge of 850 mA charge limited over the avg 600 mA as it is an 6 cell 6 Amp battery pack.

    ...And yet I can run an automotive fog light H3 from the CUI, and other than heat from the DC/DC, the bulb glows quite adequately.
     
  19. GromTag

    GromTag Active Member

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    Well.. treat these things like hampster wheels, Loaded an 100mA green cased filament bulb across the CUI's output, light came on, then applied the fan, then startup/shutdowns, xempt this time at one of the start ups I pulled the bulb from the circuit as the fan was spooling (each power start attempt from the CUI the fan cranks hard before the auto shutdown so the current is there) right as the fan was spooling up, the bulb was removed, I now have an annoyingly loud and blaring fan, still running. Can also re apply the bulb without the supply shutting on/off again, heat generation from the CUI is a bit much.
     
  20. ADWSystems

    ADWSystems Member

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    I just tried something similar. No luck. I had the pump and resistors in series, turned on the pump (but it didn't actually start), then I jumped out the resistors. The power supply shutdown. I also placed the resistor in parallel to the motor, then removed it. No lick, the power supply continued to cycle. I believe the latter is as you described in post #18. Guess the question to you is, how long did the fan start to spool up before the power supply shutdown? I don't have a stopwatch but I would guess the pump runs for less than one second.

    The question remains, what will it take to run this pump from a power supply?
     
    Last edited: Aug 25, 2017
  21. GromTag

    GromTag Active Member

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    It's a large CPU cooling fan (model B35502-35), and at the term velocity 3600 rpm type fan, the cut out seemed right at max term, est 2800-3400 rpm, I need to find that on semi ADM1027 computer fan control IC. It's somewhere..

    Well that the current consumption of the pump whilst running from the battery was 3A, and the pump did operate from the battery and yet not an 20Amp supply, thoughts are that the pump being inductive can be the role in the problem thus far.

    However with the pump playing 3A off the battery and with only 1V drop from the supply with an 5R resistor... the supply with resistor state that the pump in that scenario would be near the 50R resistance whilst the battery at 3Amp then places the pump at around 4R resistance.

    What gauge wire is assembled to the pumps common returning to the supply? if the gauge is to small, the voltage value can climb back from an inductive source and produce ramps.

    --------------------
    My views on that are limited as when it happened in the past, I just changed the common to an larger wire with the thoughts of current flow and voltage statement, being these devises rely on voltage value to determine their playing field on output only to note the current when it's being exceeded to respond only then to shut down.

    Possible current drive, pump start, then sudden ramp back resulting in over voltage detection = shut down, directing back to your inrush current factor.

    That was with an XBOX 360 power supply with protection that could not start up my X2, 500 millifarad caps from a depleted stage without auto shutting down. Never resolved that, just switched to an PSU with an external dual P channel driver and an comparator that when the cell was depleted, the charge was driven though the 50R resisted P-channel FET, then when 8V was reached the other non resisted P-channel switched on to direct drive.
    --------------------

    It a plug pack (if available) with and rating over 1 Amp can drive the pump even slightly, then again that : problematic : supplies output is not up to the task. Even adding a diode in series to the pump and filter capacitor after the diode across the positive/negative terminals onto the pump would not stand much chance.

    :edit: added the reference to which supply I was referring to
     

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