Creating 240v from two 120v outlets

GooeyGus · Feb 24, 2009

Just for the record, this outlet will NOT be for powering a 3-phase laser, I wouldn't want to risk the cathode voltage sagging and turning the cathode into butter.

I was really wanting to run my HGM5 on this outlet (240v, 35A, singe phase) but I'll probably just build a 25ft extension cord to run from the dryer outlet. I dont plan on really trying this, I just wanted to see how 'possible' it was, in case I ever needed to run something that required 240v but a small load. I wouldn't try to pull 35A out of two 120v outlets

Benm · Feb 25, 2009

240V/35A is a whole lot of power... do you even get that for a dryer?

For smaller load just transforming 120 to 240 on the spot is probably feasible - those 'moving transformers' arent that expensive.

potatorage · Feb 25, 2009

I think the dryers here use less than 30 amps-- the outlets are rated for 30 amps

DTMF · Feb 25, 2009

http://en.wikipedia.org/wiki/National_Electrical_Code_(US)

CRFultz · Feb 25, 2009

GooeyGus said:
Just for the record, this outlet will NOT be for powering a 3-phase laser, I wouldn't want to risk the cathode voltage sagging and turning the cathode into butter.

I was really wanting to run my HGM5 on this outlet (240v, 35A, singe phase) but I'll probably just build a 25ft extension cord to run from the dryer outlet. I dont plan on really trying this, I just wanted to see how 'possible' it was, in case I ever needed to run something that required 240v but a small load. I wouldn't try to pull 35A out of two 120v outlets

Dryer circuits are indeed rated for 30 amps, Electric stove/oven circuits are usually 50 amps. For a 240 35amp you would have to move up to a new Nema plug rated for such (such as a welding receptacle). Normal store bought Extension cords are not capable of that much load. A number 8 run in BX to the breaker box is advisable if your service can handle it.

For a small load (up to 2000va) I would use a power conditioner. I use a Escort Micro power Conditioner from Topaz. (Square D).

It will take a 120 and give you 240. I only use it for clean power at 120. Changing the connections will give you 240 single phase

GooeyGus · Feb 28, 2009

Yeah I just bought a shit ton of cable (20ft) so I can run the laser from my room. I just need to wire on the plug and I should be good to go... I'll post some pics in the multimedia section. ~3W single phase laser = awesome. The cable I got is rated for 300v, it's braided so it's not super stiff, and is 10 gauge wire. Well, the cable contains three 10 gauge wires, but you know what I mean. I wanted to get 8 gauge but they didn't have any so I settled for this.... I'm sure it will be fine.

Cyparagon · Feb 28, 2009

Yes it will. mine only heats up a little bit and I'm running a 1HP motor from the same cord.

Is it true your HGM only goes up to 20A?

GooeyGus · Feb 28, 2009

I'm not really sure how high it goes but I know it does more than 20a haha. It blows my 30a breaker at around 26A tube current.... As far as I know it should I up past 30... I'm not sure what the designed limit of the psu is... Isn't it around 35A?

wolfblue · Mar 3, 2009

Those two outlets are not like two batteries to be wired series. They are like one battery. You try this two extension cords thing and bad things will happen. Like dead short for the one battery in the wall.

You would never have both legs or phase's in the same room. Get a step-up Xformer

DTMF · Mar 3, 2009

GooeyGus said:
I'm not really sure how high it goes but I know it does more than 20a haha. It blows my 30a breaker at around 26A tube current.... As far as I know it should I up past 30... I'm not sure what the designed limit of the psu is... Isn't it around 35A?

cool good to see you got it all wired up "safely" . you may be able to change out the breaker on that outlet for 1 rated for higher amp's . woot main's power fun

http://www.drillspot.com/products/286992/Square_D_-Your_One_Source-_QO240CP_40A_DP_Circuit_Breaker

rkcstr · Mar 3, 2009

Heh, all that power reminds me of the audio setup I have at my mom's basement... about 5500W worth of power amps running some big speakers.... I run it all off two outlets, but I'm pretty sure that combined the 4 amplifiers have the potential to draw >25A on each circuit! Probably close to 60A for both circuits combined at full power... the 12ga extension cords get warm

It's kinda funny because a couple times already I've been home for break and playing my Xbox on the speakers (Fallout 3, you FEEL each shot and explosions scare the crap out of you and everyone in the house! ;D), and then my mom turns on her bathroom light on the floor above and POOF, there goes the breaker, haha.

Cyparagon · Mar 3, 2009

wolfblue said:
You try this two extension cords thing and bad things will happen

Only if you don't know what you're doing, and you obviously don't.

wolfblue · Mar 8, 2009

So Cyparagon has both legs in the same room. I don't. It all comes from the same 15A breaker. I'll be in the laundry room or garage to run a argon. Cyparagon can tell I that don't know what I'm talking about. But I just wish to caution others that like me , don't know what they are doing. I'm one of the reasons they put the breaker in the box.

MarioMaster · Mar 8, 2009

Yes for anyone that doesn't know what they're doing, trying something like this would indeed be a bad idea. BUT - You can wire it so some outlets are wired with L1 and some are wired with L2. This way you only need a hot connection from two outlets to obtain a 240v differential. This way is also fool proof (so long as you use polarized plugs) as if you were to plug into two outlets of the same line connection, you'd just get nothing.

No explosions with this method

Eplosions come from trying to connect hot to neutral - the only way this will NOT cause an explosion is if you have an isolation transformer.

Also - step up transformers to run an argon laser are a bad idea. Even the smallest argon lasers draw over a thousand watts, gooey's laser draws over 6000 and there are still larger argons to be had.

wolfblue · Mar 8, 2009

So then if you do get 240v with two polarized cords. And then inadvertently plug then in the wrong plugs, nothing bad happens ?

Cyparagon · Mar 8, 2009

Aside from the appliance not working, correct.

wolfblue said:
So Cyparagon has both legs in the same room. I don't.

No they're generally not in the same room. But that's what extension cords are for.

MarioMaster said:
Eplosions come from trying to connect hot to neutral - the only way this will NOT cause an explosion is if you have an isolation transformer.

Or a circuit breaker.

MarioMaster said:
Also - step up transformers to run an argon laser are a bad idea. Even the smallest argon lasers draw over a thousand watts

So you need a large transformer. Why is a large transformer a bad idea?

Creating 240v from two 120v outlets

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