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# Can i convert from DC to AC? Answered

My dad wants me to make an olive shaker comb work from 230VAC. Is that possible with something like a transformer? Ours runs at 12 to 33v, 500W and 4Ah. Is it possible for me to make a transformer box thingy that can power the machine from the home power grid?

-Miguel Conceição

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## 12 Replies

Toga_Dan (author)2017-01-29

how much distance from tree to outlet?

Jack A Lopez (author)2016-11-14

come in all sizes, although I think the power converter you need for your electric shaker rake probably needs to be kind of beefy. It will probably be bigger, heavier, more expensive, than the little black wall-wart, that comes with a mobile phone.

I mean if your shaker can actually draw 500 watts, at 33 volts, that is a current draw of around 15 amperes, since (33 V)*(15 A) = 495 W

How much power does it draw at 12 volts? Who knows, right? Probably a lot less. Maybe 100 W? (12 V)*(8 A) = 96 W

How much power does it draw at 24 volts? A similar question to ponder.

And more importantly, how much electrical power, in watts, do you actually need to shake the olives loose?

I am guessing you want a DC supply, with output voltage approximately 12 to 36 volts, and capable of throwing currents of approximately 10 to 15 amperes.

There are a bunch of power adapters out there made to supply 12 volts, including uh, cars. I think the cigarette lighter socket in a typical car can supply what, like 10 A, 15 A? That might be something to try, if you have a car, or can borrow one.

Regarding 12 VDC supplies that plug into the mains, I recall the power supply for the Xbox(r) 360 was pretty beefy. It was 12 V, at like 14 A, or 16A, something like that.

Maybe if you stacked two of those XBox power bricks in series you could get 24V at 14A?

Or maybe you could find a used golf cart charger? I think 24 volts is a somewhat popular voltage for golf carts. Guessing one of those would be capable of supplying 10 or 20 A, or so.

It looks like this olive harvesting equipment, and new batteries for the same, these are quite expensive new, retail.

http://www.shopmancini.com/en/148-olive-harvest
http://www.evvvai.com/en/60-electric-rakes

Those links I found via Google(r), I don't know if those prices are typical, but if they are, this stuff seems godawful expensive.

Miguelc1 (author)2016-11-14

I have it currently running from our truck, the problem i that "soon" we will have more olive trees and the truck will no longer be able to go to those places. However we have a nice neighbor next to that field and he's kind enough to lend power and even help out. So I'm trying to use 230VAC to run the shaker, and something i forgot to mention is that the shaker has a cable with a "thing" (I don't really know the name of it) in one end that connects to the truck's battery and turns 12VDC to 33VDC.

iceng (author)2016-11-14

Plant your trees to a plan that lets a basket trailer to follow a shaker along double rows. And a simple hydraulic pump system works best as a tree shaker...

Downunder35m (author)2016-11-14

That means you either need a 12V or a 24V supply capable of giving you the amps you need to run the machine.
I don't know about the differences on these voltages but if 12V is sufficient for your needs then as said an ATX power supply should do it.
Another option, although a bit costly would be to use battery charger that is switchable between 12 and 24V.
Best the old and heavy style with a real transformer working in it.
They only provide a very bad DC, which is good for charging a battery but not so much for a motor.
To overcome this problem you can either add a battery or a big electrolytic capacitor between charger and motor connection.
This will smotth out the DC so the motor runs fine.

Downunder35m (author)2016-11-13

You need a power supply that is strong enough to supply the power you need.
If 12V is sufficient you could use an old ATX power supply salvaged from an old computer, more than enough info on the web how to add a switch to them to get them working without a computer.

steveastrouk (author)2016-11-13

OP says he needs AC to make something shake.

Downunder35m (author)2016-11-13

Hmmm, to me it sounded like it currently runs on batteries and he wants to run it from mains power...

steveastrouk (author)2016-11-14

Yeah, I can read it like that too this morning.

rickharris (author)2016-11-14

for Mains to DC

https://www.amazon.co.uk/s/ref=nb_sb_noss?url=sear...

Amazon search for 12 volt 5 amp power supply.

Otherwise as said your looking at an inverter but 12 volts at 5 amps is only 60 watts and their are many made for car use to convert 12 volts to mains again Amazon or ebay.

ideal_writer2 (author)2016-11-13

I think there are now potable DC to AC converter all around.The OP can purchase one, It will save you a lot of time

-max- (author)2016-11-13

If you want AC -> DC, then the old fashioned way to do it is to use a transformer (to get the desired voltage), followed by a bridge rectifier (to turn that AC into choppy DC), followed by a smoothing capacitor (to smooth out the choppy DC even with moderate load).

If you want DC -> AC, then you need an inverter, and given that you are asking a relatively simple question, I assume you don't know enough to build your own, so your best bet is to buy one. Modified Sine Wave inverters are cheap and generally efficient, but are also electrically noisy, containing many harmonics, which can cause additional power losses in semi-reactive loads. Pure-sine wave inverters are much more pricy, larger, heavier, more complicated internally, generally a little less efficient, but produce a realistic output voltage and are well suited for driving things like inductive loads.