Air Pump

Discussion in 'Electronics Repair' started by Steve87, Jan 12, 2018 at 4:46 PM.

  1. Steve87

    Steve87

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    Hi All, hope someone here might be able to help?

    I have an air pump which has stopped working, all the wiring seems okay so I think it is the variable voltage controller.
    I can't seem to get a replacement anywhere, can't even get in touch with the manufacturer.
    I show a couple of photos so may be you might be able to suggest a remedy.
    Thanks for looking. Case.jpg R3.jpg
     
    Steve87, Jan 12, 2018 at 4:46 PM
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  2. Steve87

    hevans1944 Hop - AC8NS

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    Visit this link and tell us if the item on that page is what you have (ACO-9630 Air Pump). If so, send an e-mail inquiry to info@hailea.com (address at bottom of the linked page) and ask if the company will either sell you another pump, or another motor speed controller, or maybe both, mated and integrated together, so you can enjoy "Continuous operation and long service life" as it says on their web page.

    Methinks if you paid more the £1.0 (including shipping and handling) for this pump, you wuz ripped off royally.
     
    hevans1944, Jan 12, 2018 at 5:29 PM
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  3. Steve87

    Steve87

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    Thanks for the reply, have sent emails to this address but no reply, been trying for ages. Cost when I bought it was £30 approx. Is a very good pump, when working.
     
    Steve87, Jan 12, 2018 at 6:36 PM
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  4. Steve87

    73's de Edd

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    Sir Steve 87 . . . .

    Go 2 inches out from the PCB and cut 1 of the the brown wire PAIR, go 2 inches further down and cut the other wire . . .so that the cuts then will be staggered on re splicing -soldering and taping.

    With a soldering and heat shrink tubing being the most preferred.

    Get a Drop light-table-Torchierre or desk lamp and use a 40-60 watt incandescent lamp in it and test by turning on and leaving on.

    Connect the lamps plug blade connectors to the PAIRED two brown wires closest to the PCB .
    Power up the unit and see if the adjustment pot varies the lamp brightness.

    If no brite adjustment shows the, " Q1" TO-92 triac is probably bad.

    If it adjusts lamp brightness, the air pump motor must be bad.
    Re splice the brown wires and re insulate..



    73's de Edd
    .....
     
    Last edited: Jan 12, 2018 at 7:20 PM
    73's de Edd, Jan 12, 2018 at 7:02 PM
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  5. Steve87

    hevans1944 Hop - AC8NS

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    So maybe you got a good deal on the pump, but just bad luck on the motor controller. All is not lost if you can verify that the pump motor still works.

    Maybe you can purchase a PWM controller from one of the many Asian sources available on eBay. What to get would depend on what kind of motor the air pump uses. That will require some experimentation on your part. I doubt very much that the motor uses anywhere near the 110/220 VAC, 50/60 Hz specified as the input voltage. It is probably a permanent-magnet, brushed, DC motor that would run fine on anywhere from 2 V DC to maybe as much as 24 V DC.

    So, I would open it up, find the motor wires, disconnect them from the faulty speed control, and start connecting the motor wires to dry-cells, connected series, until I found a voltage that ran the motor at whatever maximum pumping speed you wanted or needed. Pay attention to polarity and make sure the motor rotates in a direction that results in pumping. Then order the appropriate PWM controller after measuring the motor voltage and motor current at the maximum pumping speed.

    If you have any electronics skills (this IS a hobbyist forum) you can make your own PWM controller... probably not as cheap as you can buy one from Asia, but a lot more fun, and a learning experience to boot. I would suggest using a step-down transformer to get into the right ballpark for the DC motor supply, just for safety reasons. It is dangerous to mess around with mains power applied to low-voltage circuits without a transformer to isolate and limit the current available to the maximum necessary for circuit operation.

    If motor insulation is adequate, you can theoretically use PWM at the line voltage (after rectification) to control motor speed, selecting a maximum duty-cycle for the PWM wave form that does not overpower the motor. This is a risky and dangerous approach in my opinion. You can easily "let the smoke out" and ruin the motor by accidentally operating with too large a duty cycle. Also, it places a high voltage stress on the motor windings that may cause early failure if you are lucky, or immediate failure if you are not lucky. So, use a step-down transformer, rectify the secondary voltage to the proper DC voltage level, then use PWM with a 0 to 100% variable duty cycle to drive the motor.

    Edit: Of course all the above depends on (1) your pump uses a brushed DC motor and (2) the motor is still operational and only the controller is bad. If you do the test Edd suggested, that will determine whether the controller is bad or not. Let us know what you find out and we can proceed from there...
     
    Last edited: Jan 12, 2018 at 7:08 PM
    hevans1944, Jan 12, 2018 at 7:03 PM
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  6. Steve87

    Alec_t

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    What markings are on the semiconductor device (the black three-legged component)?
     
    Alec_t, Jan 12, 2018 at 7:03 PM
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  7. Steve87

    Steve87

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    Thanks for your information heavens 1944..

    Alec the closest I can get to the text is....MAC/07A6/M922
     
    Steve87, Jan 12, 2018 at 8:18 PM
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  8. Steve87

    Alec_t

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    Ok. Looks like the semiconductor is a 0.6A 400V sensitive gate triac. If it's fried, a suitable replacement (perhaps with a higher current rating) should be easily obtainable.
     
    Alec_t, Jan 12, 2018 at 8:37 PM
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  9. Steve87

    duke37

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    I would guess that, with a triac, it is a series wound (universal) motor. Measure the voltage going to the motor with an AC volt meter.

    A C106D is the classic sensitive gate triac and much more robust.
     
    duke37, Jan 12, 2018 at 9:10 PM
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  10. Steve87

    Minder

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    There is now 230vdc motors used in these type of appliances, they use a triac in series with a bridge, with the motor on the bridge output.
    If you have access to the motor leads and short them together and detect any resistance when spinning the shaft, then it points to a P.M. DC motor.
    M.
     
    Minder, Jan 12, 2018 at 9:50 PM
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    hevans1944 likes this.
  11. Steve87

    Alec_t

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    Re post #8, I've just noticed that Google gave me info for the MAC9706. Could the component marking be that?
     
    Alec_t, Jan 12, 2018 at 11:38 PM
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  12. Steve87

    hevans1944 Hop - AC8NS

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    I wasn't aware of this technology, probably an off-shoot of using rare-earth permanent magnets for the stator magnetic flux. I wonder how long it will take for this to appear in things like corded hand drills and the like? Or has that already happened and I just haven't noticed? (I am getting older, ya know...)

    At first I thought "electrical resistance? with the motor wires shorted together?" Then I realized that you meant mechanical resistance, an opposition to rotary motion of the shaft because the DC motor was behaving as a DC generator driving a short-circuited load. This "test" works with any PM DC motor having decent bearings and a strong stator magnetic field. It is interesting to observe the facial expressions of laymen who first try to (easily) spin the shaft of a largish PM DC motor with the armature circuit disconnected, and then again (not so easily) with the armature shorted.

    Thanks, @Minder for that little factoid. In view of the speed control circuit's simplicity. it probably IS a universal-wound AC/DC motor. Either way, if the motor is still good, a cheap Asian PWM controller should get @Steve87 back in business.
     
    hevans1944, Jan 13, 2018 at 4:13 AM
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  13. Steve87

    Minder

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    Yes, you can also do it with a BLDC to determine the pole count, i.e. short the three stator winding connections and rotate 1 revolution and count the 'bumps'.
    Most of the 555 PWM controllers from the Far East do not go that high in voltage and also require a DC supply, the ones I have checked out at least.
    The DC PM. motors are appearing in Kitchen appliances now.
    M.
     
    Minder, Jan 13, 2018 at 4:29 AM
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  14. Steve87

    Steve87

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    Yes could well be.
     
    Steve87, Jan 13, 2018 at 9:09 AM
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  15. Steve87

    Steve87

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    Thanks for all your help, will be off to Maplins today to see what they have.
     
    Steve87, Jan 13, 2018 at 9:12 AM
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