I have a “Perfect Air” air mattress that I put on my futon for when Guests stay over. I lost the plug to the electric air pump.
I do, however, have a universal AC adapter that can be set to + or - polarity and anywhere from 1.5 to 12V DC output.
Any guesses what settings I should use? Is there any way to figure this out? Will I burn down my house if I use the wrong setting?
The documentation gives me no hints (it does tell me that it is an “AP-107 Rechargeable 110- 120 Volt pump with AC adapter 5 Ni-CAD battery”). I have already called the company, and the lady said that the “person who knows all about this type of thing isn’t in today.”
Unless you can find the exact voltage and minimum current specification, I highly recommend you wait for the technical person at the manufacturer. Connecting the wrong voltage can damage the pump or the power supply, and if the supply cannot provide enough current, you could start a fire from overloading the adaptor.
It’s probably 12 volts, though, since these things are designed to be taken camping and whatnot, so it needs to be able to be powered by a vehicle. Of course you also need to know the polarity and the current requirements. I’d guess a couple amps at least. I’d still wait.
Usually the power requirements will be either on a lable or molded into the body of the device near the power socket. It should list its power requirements as something like: DC in 12V, 800 mA.
Also, when using a universal adapter make sure it’s rated for a higher amperage than the device needs. So if the pump draws 800mA, use an adpater rated for 1000mA or higher.
The pump may have a polarity indication near the place where the adaptor plugs in. If you can get the polarity right, you may succeed by starting at the lowest available voltage and working your way up until it seems to be pumping as it should. (This assumes your universal AC adaptor will handle the current draw.)
If the device can be powered by 5 Ni-Cd batteries, this implies about 6 volts.
OTOH, you may save yourself some trouble by waiting until “the person who knows all about this type of thing” returns.
Update. Well, my inlaws are now in town. I plugged the thing in for about 6 hours at 12 V. (It says not to run it while plugged in). It worked fine. <shrug>.
And the pump itself has absolutely no indication of what power it needs – I checked thoroughly.
Echoing AcidKid, if you can find the mattress in a store, open up a new box and see if the power block has the specifications listed on it. (eg: Output 6 Volts DC 350mA). Write them down and match your universal adapter to them. The notation for polarity is usually an open ring with a dot inside. If the polarity is indicated, there will be a + or - pointed at the dot in the center depending on if the “tip” is +positive or -negative.
Also, though many universal adapters come with virtually no instructions, check for any warnings on driving inductive loads (like a pump motor). These adapters are ofter remarkably cheap. The high current adapter that came with it may have a component like a kickback diode or a beefier ‘back end’ to accomodate the motor.
Or it might need them, but not have them. You’d be amazed how common open-circuit or dropped voltage power supply failures are, especially on devices intended for infrequent use. Wall-warts are a common place to shave pennies. Devices often work, albeit less well, as it fails (it only has to outlast the warranty), and consumers don’t hold power supply failures against the product as much as they do other failures [unless word gets out that the problem is widespread)