11/18/2023 0 Comments 12 volt car battery ac or dcIf high pressure is available, but the pipe is very small, there will not be many gallons per minute and the work done by a waterwheel won't be very much. The amperage, or current, is similar to water flow in gallons per minute. The voltage is similar to water pressure. If higher current is used, the voltage will be lower.įor those who don't work much with electricity, it might be useful to think of a water analogy. If less current is being used, the voltage (and motor speed) might be considerably higher. The rating on the power supply is a certain voltage at a certain current draw. The lower the voltage, the lower the speed of a DC motor. The reason the drill doesn't have much power is that the voltage from the power supply goes down as the current use goes up. Higher current will supply higher torque. You also might find still filings sticking to it. Usually, if the equipment has a permanent magnet motor, the magnets are visible or the side of the motor will attract a screwdriver tip or a nail. If this is the case, AC will just make the drill buzz rather uselessly at 60 hz. However, some portable equipment has permanent magnet motors, so the field does not change polarity during the AC cycles, but the armature does. They have electromagnetic field windings, so the field polarity changes with the armature polarity, thus keeping the motor going in the same direction during the AC polarity change. Most cordless drills and other items do have motors that work on AC and DC. (Traded it, really, for smarter chargers and more powerful batteries.) It's premade for this mode of operation! Somewhere along the line, interchangeable batteries did away with the on-tool charging jack, and we lost the ability. It's funny, I have an ancient 7.2v Black & Decker drill, with a built-in battery and a jack on the bottom for the wallwart. There was a long thread about exactly this subject over at toolmonger some months ago. You should consider adding some batteries or capacitors to supply the motor's momentary demands for power, which could be replenished during idle time. That's why a 1200mA wallwart has such a tough time here. So even if the 1400mAh battery pack would run the drill for a solid hour, there were still some moments in there when it was supplying well over 1400mA of current. Spinning freely, they draw almost nothing. ![]() (Not really, look up "Peukert's effect", but rough numbers will do for now.) Electric motors draw lots of current when they start, or when they're pushing against a load. Are there better ways to do this? Absolutely : )Ī note about transformer sizing: The battery rated at 1400mAh will theoretically put out 1400mA for 1 hour, or 700mA for 2 hours, or 2800mA for half an hour, etc. Nothing fancy, not a lot of pre-planning to get in the way of getting something finished. You may notice a theme here-this is a cheep fix with what I had on hand. I may end up finding a bigger transformer, or trying it on AC current-but not untill I don't need this one any longer. That and i don't know how much I can pump threw the motor before it burns out. I don't feel comfortable enough with electronics to risk the parts. Too expensive to go out and get some just to play with. Thus, no battery shell to reload : ) Q Use a Zener transorb/5 f. While trying to find out which cells in the battery were live and which were dead, I lost the parts. If it was a good brand name on the other hand. Brand new unit would be about $20 and be ready 'out of the box.' A new set of batteries and a charger for them would not be worth the time or money. The wall wart was free at another garage sale. ![]() The drill was $5 (with case, extra drill and 2 battery packs) and worked for a while. ![]() In the spirt of Instuctables, I'm adding some of the sugestions for improvement and why I didn't do things that way in the first place. Turn an old battery powered drill into a wall power unit.
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