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AC to DC power converter? Answered

I'm looking for an AC to DC power converter.  It needs to be 110V input and i need at least 30 Amps of output.  Output voltage is not as crucial but at least 50V would be ideal.  I need either a product i can purchase or instructions on how to build.  Im not an electrical guru by any means so purchasing a product would be better.  I am aware that this is going to be costly.  It does not have to look nice.  I will be wiring it directly into a unit and will have my own casing.  Can anyone help?

Discussions

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steveastrouk

2 years ago

That's a BIG DC supply, 1.2kW. You can buy 48V as a standard output, but 30A is not going to be cheap. Alternatively, you MIGHT look at a DC inverter welder from the likes of Harbor Freight, which will probably push out around 48V, though I think you'll have to be careful the supply is continuously rated, or you will have to add some cooling.

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aeudysteveastrouk

Answer 2 years ago

As of right now we are using a welder. I am trying to down size for convenience. How expensive do you think I will be looking at? It will not be running continuously. Only for about 30 seconds at a time with several minutes in between for cool down.

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steveastroukaeudy

Answer 2 years ago

How big is the welder you have ? The HF one is about 12 x 6 x 6 inches, from memory. Unfortunately your profile doesn't say where you are in the world to offer better advice on suitable equipment.

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aeudysteveastrouk

Answer 2 years ago

I am in Texas. That's not too big. Expensive?

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steveastroukaeudy

Answer 2 years ago

The one I used to have, and which would have suited the project is sadly obsolete. This is very close though

http://www.eastwood.com/arc-80-with-tig-torch.html

And at reduced output amps, you can probably get 100% duty cycle.

But take a look at "48V 1.2kW DC supplies", like the link below - A bit of searching might get just what you need.

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aeudysteveastrouk

Answer 2 years ago

How difficult do you think it would be for me to do away with the outer shell and mount it into a different housing?

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steveastroukaeudy

Answer 2 years ago

Not too hard at all, but some more project information, and we might find you a better option. As you have already added you need "as smooth as possible", I would suggest an off the shelf power supply

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aeudysteveastrouk

Answer 2 years ago

Can you recommend a power supply? Ive had trouble finding one with enough output.

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iceng

2 years ago

Starting with a primer on a TR (Transformer Rectifier) power supply

You will probably have to click the pic to see the entire image.

The 110 vac transformer lowers the voltage to 48 vac and the DC-Bridge also called a full wave Rectifier produces a pulsating DC output with surprise 68 volts peaks TOP.

If you add an 100 volt capacitor of 1000 uF the ripple is reduced MIDDLE.

If you add an 100 volt capacitor of 10,000 uF 80v capacitor the output is all DC BOTTOM.

Next lets see where to get the parts

Later game for me now...

RippleRECTIFIED.jpg
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icengiceng

Answer 2 years ago

Do you need smooth DC current or will pulsating current do ?

I am fascinated, if it is no secret, what do you search for in the drilling ground ?

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aeudyiceng

Answer 2 years ago

The current needs to be as smooth as possible. The current is used by a probe in the drill bit. The probe measures the intensity of the current going through the wires on top of the ground to triangulate the exact location of the probe in the ground. An intensity of at least 30 amps is required, which for the build I am working on that would be sufficient for the probe to pick up the signal.

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icengaeudy

Answer 2 years ago

Smooth is a problem for size, cost and complexity. You however have a positive feature in timing 30s ON and 120s off.

That is using 30A x 1/2min = 15Amin

Simply put four or five 12v batteries in series to get your smooth voltage and current, then use a high current SCR in a power version of a lamp dimmer to recharge the batteries off the mains for the 2 minutes off duration and disconnect the main before probing the ground. No transformer is needed just a power inductor that is easy to make. Batteries are only 50% efficient so you need to return a current of 15Amin x 2 => 30Amin / 2min = 15 amps for two minutes.

...................................................................

You could also put ten 12v batteries in series with an inductor charging them from a bridge across the main line at 7.5A for 2 min and then parallel five with five for the 30s and recharge as ten again.

If some of this is interesting let me know and ill explain how to make a power inductor real low cost.

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aeudyiceng

Answer 2 years ago

The only problem with that is the size. Im looking for somthing around 18"x8"x4" or smaller.

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icengaeudy

Answer 2 years ago

Then you must use high frequency 400 cps and above with real regulators.

Aircraft use 400 Hz because the transformers are 60/400 smaller and lighter.

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aeudyiceng

Answer 2 years ago

That sounds expensive. I'm trying to keep it under about $600 if possible.

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aeudyiceng

Answer 2 years ago

I am not very familiar with any of the things you mentioned. How difficult would it be for me to do this myself? I understand the concept of what your saying but will I be able to do it with little knowledge of the system?

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Downunder35m

2 years ago

If someone is sdking for such power levels but has no clue about it, there is only one advise I cn give:
Get professional help from a local sparky before you burn your house down.

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aeudyDownunder35m

Answer 2 years ago

I wont be using it in home. It will be used for directional drilling. As of right now we are using a welder to charge a wire coil for tracking purposes. It will only be used for short periods of time. About 30 seconds at a time with several minutes in between to cool down.

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Downunder35maeudy

Answer 2 years ago

Well, you could have mentioned that ;)
If it is for tracking only, did you consider using shorter pulses?
I mean instead of 30 sec full, a lot of bursts in the miliisec range.
Adapting for this would mean you could use a quite simple strobe circuit or even an electric fence generator - of course it would need quite a big step down transformer (ferrite core) to get from the HV to a low voltage impulse with insane amp levels.
To increase the output power for the pulse you simply add more capacitors into the charging stage.

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aeudyDownunder35m

Answer 2 years ago

would it take much space? I'm trying to down size from a welder. Also the positive and negative leads have to separate so that a forward and reverse current can be ran through the wires. Other types of tracking tools can run off of alternating currents on 1 wire but the one that i am using has to be a complete circuit that can be reversed.

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Downunder35maeudy

Answer 2 years ago

Space is relative, the fence generators are often not much bigger than a cigarette box, the ones with the battery inside bigger of course.
Output transformer can be about the same size, so again quite small.
Question remains if your setup will work with short pulses instead of a constant feed?
If not I suggest to try one of the other solutions offered.
An electronic welder would be the next smallest thing and pricewise still atttractive.

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steveastrouk

2 years ago

https://www.allhdd.com/?subcats=Y&pcode_from_q=Y&pshort=N&pfull=N&pname=N&pkeywords=N&search_performed=Y&src=ggl&q=437573-B21&dispatch=products.search&gclid=Cj0KEQiAoby1BRDA-fPXtITt3f0BEiQAPCkqQZKEYDEm6DbMQi7r-nZ3Vpd_IEeTSpvzHVomNetn2bcaApfn8P8HAQ