Oops, sorry there gareth. I didn't mean by my choice of your quote there to imply offense taken. Quite the opposite. I was reassured that even someone far better versed in domestic level wiring might also misapprehend what is going on in my three prong 240 outlet.
Thank you for the contributions.
I am very reluctant to modify this welder in any way. It is almost beyond warranty so I'm not real concerned with that, but it's a very complicated machine. I have no concern about tapping into the power off the main switch however, if I can do it safely.
Obviously, I could dispense with all of this worry by simply putting a three prong 120vac cord out of the back of the cooler, use another outlet, and a switch on the panel. Aside from the fact that I might forget one day to turn it on - and then destroy my 100dollar tig cables - I'm just being very stubborn and 'perfectionist'.
If anyone can relate to this sort of perfectionism, I hope it's the members of DiyAudio. This is an auxilliary part of my welder. It will actually be fastened permanently to the bottom of the machine. I want it to turn on and off with the welder. I'll go to some pretty worrisom ends to accomplish this deed.
I could also put in the 120vac three prong cord/plug, use another outlet, and throw a 220vac coiled relay across the welders mains to switch the cooler on. This is practical, but not nearly as elegant (perfectionist) as I'd like.
The transformer is the way to go.
Everything comes down to compromises.
I have a lightweight compact 120/12 SMPS rated to two amps.
I have a motor that requires 120v.
I have a little Franzus travel 'adapter' rated to 1600 watts that could serve the motor well enough but is not recommended for "electronic" devices (such as a computer, or my smps I might assume).
Soooo.... I can try to find a 500watt stacked core transformer but so far eight pounds is the smallest I've seen (1/3 the weight of this entire project).
Or.. I can use a stacked core 120/12 transformer which is only twice the size and weight of the smps and capable of 1.5amps.
..then, perhaps, I can xform the 240 to 120 using the very lightweight and compact travel 'adapter' and chuck the smps for the stacked core little boat anchor for 120 to 12vdc.
..which now allows me to .... 240vac to 1600watt 240/120 travel adapter to 2.5amp 120vac fan motor and 120vac/12vdc stacked core xformer (which powers two muffin fans and some panel meters) Hmmmmm.
Dammit.
All this while I was laboring toward simply hooking up this cooler to the ground and one leg of the 120. Obviousy I'm glad I did more research. I'd still be way ahead of the game if I could discover some compact means of xforming 240 to 120 to power the motor and the SMPS. I'm gonna have to rearrange space to replace the smps with the stacked core.
Thank you for the contributions.
I am very reluctant to modify this welder in any way. It is almost beyond warranty so I'm not real concerned with that, but it's a very complicated machine. I have no concern about tapping into the power off the main switch however, if I can do it safely.
Obviously, I could dispense with all of this worry by simply putting a three prong 120vac cord out of the back of the cooler, use another outlet, and a switch on the panel. Aside from the fact that I might forget one day to turn it on - and then destroy my 100dollar tig cables - I'm just being very stubborn and 'perfectionist'.
If anyone can relate to this sort of perfectionism, I hope it's the members of DiyAudio. This is an auxilliary part of my welder. It will actually be fastened permanently to the bottom of the machine. I want it to turn on and off with the welder. I'll go to some pretty worrisom ends to accomplish this deed.
I could also put in the 120vac three prong cord/plug, use another outlet, and throw a 220vac coiled relay across the welders mains to switch the cooler on. This is practical, but not nearly as elegant (perfectionist) as I'd like.
The transformer is the way to go.
Everything comes down to compromises.
I have a lightweight compact 120/12 SMPS rated to two amps.
I have a motor that requires 120v.
I have a little Franzus travel 'adapter' rated to 1600 watts that could serve the motor well enough but is not recommended for "electronic" devices (such as a computer, or my smps I might assume).
Soooo.... I can try to find a 500watt stacked core transformer but so far eight pounds is the smallest I've seen (1/3 the weight of this entire project).
Or.. I can use a stacked core 120/12 transformer which is only twice the size and weight of the smps and capable of 1.5amps.
..then, perhaps, I can xform the 240 to 120 using the very lightweight and compact travel 'adapter' and chuck the smps for the stacked core little boat anchor for 120 to 12vdc.
..which now allows me to .... 240vac to 1600watt 240/120 travel adapter to 2.5amp 120vac fan motor and 120vac/12vdc stacked core xformer (which powers two muffin fans and some panel meters) Hmmmmm.
Dammit.
All this while I was laboring toward simply hooking up this cooler to the ground and one leg of the 120. Obviousy I'm glad I did more research. I'd still be way ahead of the game if I could discover some compact means of xforming 240 to 120 to power the motor and the SMPS. I'm gonna have to rearrange space to replace the smps with the stacked core.
some info on 3wire/4wire house wiring in the USA
http://en.allexperts.com/q/Electrical-Wiring-Home-1734/220-Outlet-Dryer.htm
http://en.allexperts.com/q/Electrical-Wiring-Home-1734/220-Outlet-Dryer.htm
jb74 thanks for that. I probably already read it. I spent an entire evening chasing down these q&a on the web. The old appliances weren't necessarily (electrically anyway) more dangerous from what I can gather than the new 'up to code' variety. They either did not have 120vac components within them, or they had internal xformers to run the 120vac components, much the same way as I've been told to run mine. In any case, they did not use the ground to complete the current - leaving it to serve for safetys sake. The new code offers an easier means for manufacturers to meet safety requirements. If you have 120vac components within the unit, you no longer need an internal transformer in the product. Now you can borrow off one of the legs and use the neutral wire while still keeping a dedicated ground running back to the box.
I felt pretty stupid having to ask these questions around various electricians, heating and cooling guys, and others in the past week, but I'm now astonished (and not a little horrified) at how poorly understood all of this is among tradesmen. Simply put, this just should not be a head scratcher for people working around it as professionals.
I felt pretty stupid having to ask these questions around various electricians, heating and cooling guys, and others in the past week, but I'm now astonished (and not a little horrified) at how poorly understood all of this is among tradesmen. Simply put, this just should not be a head scratcher for people working around it as professionals.
Bluebeard -
A relative of mine moved into a newly built house recently. Very soon
We were into solving the riddle of the 3 prong dryer plug and the new 4 slot connector.
Thanks to that amazing (& relatively) new tool - the internet, I was soon
looking for and even finding an answer. (I'm not an electrician)
The way things work, I suppose it's not too surprising that even some
electricians would not be up to date on this - unless they were working
in new home construction.
A relative of mine moved into a newly built house recently. Very soon
We were into solving the riddle of the 3 prong dryer plug and the new 4 slot connector.
Thanks to that amazing (& relatively) new tool - the internet, I was soon
looking for and even finding an answer. (I'm not an electrician)
The way things work, I suppose it's not too surprising that even some
electricians would not be up to date on this - unless they were working
in new home construction.
bluebeard said:
The intro of the following article seems to talk about what you want.
http://electronicdesign.com/Articles/Index.cfm?AD=1&ArticleID=7490
Here's the printer-friendly version:
http://electronicdesign.com/Articles/Print.cfm?ArticleID=7490
how about powering the cooler from a separate regular 120V outlet, then wiring in a control relay to turn the cooler on and off that gets its relay coil energized from the 240V from the welder when you switch it on. this has the disadvantage of needing two separate cords (one for the welder and one for the cooler), but it eliminates the need for the laminated brick (lol) and ensures that the cooler will always be on when the welder is.
Hi bluebeard,
Please read again what I have posted. What you want to achieve is fairly simple.
Even though over here in the UK we wire things differently (we do not use 120Vac except for constuction sites), I have had this problem looked at by others and they agree with me.
If you really want to go down the transformer (2:1) or Switch mode route then that is fine. Bringing a new neutral from your distribution board is far simpler (and cheaper)!
You can then use the triple-pole switch to fire the three hots at the same time whilst leaving the neutral and earths unswitched. This could be your 'local' switching.
Also I have also mentioned previously you could use relays or better still a contactor to switch the hots. The benefits of either of these two methods is that you could have 'remote-control' and even 'remote-disconnection' if needed.
Delending on what outlets you have available near the welder/cooler will define what extra (if any) cabling you need.
Gareth
PS..I kind of wish I was over there now as it sounds like an interesting little job.
Please read again what I have posted. What you want to achieve is fairly simple.
Even though over here in the UK we wire things differently (we do not use 120Vac except for constuction sites), I have had this problem looked at by others and they agree with me.
If you really want to go down the transformer (2:1) or Switch mode route then that is fine. Bringing a new neutral from your distribution board is far simpler (and cheaper)!
You can then use the triple-pole switch to fire the three hots at the same time whilst leaving the neutral and earths unswitched. This could be your 'local' switching.
Also I have also mentioned previously you could use relays or better still a contactor to switch the hots. The benefits of either of these two methods is that you could have 'remote-control' and even 'remote-disconnection' if needed.
Delending on what outlets you have available near the welder/cooler will define what extra (if any) cabling you need.
Gareth
PS..I kind of wish I was over there now as it sounds like an interesting little job.
gareth said:
where did the third hot come from? and rewiring the receptacle for 4 wire 240/120 outlet may or may not be so easy for him depending on how much access he has to the existing wiring. if its buried behind ceiling and drywall, adding a separate neutral could get complicated quick.
From my understanding you take in two hots @120Vac each to give 240V. So one hot would give 120Vac.
AS bluebeard needs 240V to the welder and 120V to the cooler, then using a triple-pole switch is the most convenient method to do this.
Why not use armoured flex ( type SY not armoured cable) properly glanded as it is a welder and is likely to get a rough time to bring in your supply? This is something that needs to be ascertained on the spot though as as you have said he may not have access due to drywalling/ceiling voids or whatever, but I wouldn't have thought he would be using this in his living room or kitchen. Again this aspect can only be ascertained on the spot.
Gareth
AS bluebeard needs 240V to the welder and 120V to the cooler, then using a triple-pole switch is the most convenient method to do this.
Why not use armoured flex ( type SY not armoured cable) properly glanded as it is a welder and is likely to get a rough time to bring in your supply? This is something that needs to be ascertained on the spot though as as you have said he may not have access due to drywalling/ceiling voids or whatever, but I wouldn't have thought he would be using this in his living room or kitchen. Again this aspect can only be ascertained on the spot.
Gareth
I must be misapprehending the presense of some elephant in the room. Albeit dangerous enough to be taken with the utmost seriousness, isn't household wiring pretty much electricity 101?
I just can't get a clear picture of how 120 and 120 equals 240 without actually using a 'neutral'. One person even referred (can't recall if it was here, but I don't think so) to them as +120vac and -120vac. Come again?
I called the 1-800 tech support number for the little Franzus 1600watt 240/120 "travel adapter" and was told that it should run the 2.5amp fan load ok if it is kept very well ventilated. No problem. It's in the path of two 100cfm muffin fans at all times.
I set it up on the bench and checked it before a trial. 65vac. Hmmm
I called back the tech and he said that of course I cannot use this device here in the U.S.. We get 240 from two 120 lines, he told me, and oveseas they use 240 on one and a neutral. That much I understand. But it turns out that these 'adapters' only see current on one prong/plug and then half it internally. Brilliant! What??
So is a european 240/120 step down transformer going to expect to see 240 on one main leg and a U.S. 240/120 transformer going to expect to see 120 on each leg?
Is there a 'wiring for idiots' explanation here somewhere?
I can't really go the new 4wire plug/cable to the welder. I'm reluctant to modify the machine in any way substantially. At this time it's still a bit like a new car in the driveway. I'm even tempted to throw a coat of paste wax on it occasionally. (but i won't) I probably wouldn't even wish to get inside of it to put a relay across the switch itself. Tapping off the switch was the most modification I was comfortable with.
I really do wish to have them energize both with a single switch however, so I'll probably put some sort of multi pole knife switch on the wall behind the welder that will serve two separate boxes - a grounded 120 and the 240 that's there for the welder now. The welder/cooler will still be bolted together, just have two cords (dammittohell). I'll have to check with the manufacturer to see if it's ok to use remote power to regularly turn it off and on.
Sorry to all here if this has been a little too off diyaudio topic. I hope it's been at least a little interesting to some, and maybe even informative to others. I greatly appreciate the knowledge base in this community. I'd hate to abuse it.
I just can't get a clear picture of how 120 and 120 equals 240 without actually using a 'neutral'. One person even referred (can't recall if it was here, but I don't think so) to them as +120vac and -120vac. Come again?
I called the 1-800 tech support number for the little Franzus 1600watt 240/120 "travel adapter" and was told that it should run the 2.5amp fan load ok if it is kept very well ventilated. No problem. It's in the path of two 100cfm muffin fans at all times.
I set it up on the bench and checked it before a trial. 65vac. Hmmm
I called back the tech and he said that of course I cannot use this device here in the U.S.. We get 240 from two 120 lines, he told me, and oveseas they use 240 on one and a neutral. That much I understand. But it turns out that these 'adapters' only see current on one prong/plug and then half it internally. Brilliant! What??
So is a european 240/120 step down transformer going to expect to see 240 on one main leg and a U.S. 240/120 transformer going to expect to see 120 on each leg?
Is there a 'wiring for idiots' explanation here somewhere?
I can't really go the new 4wire plug/cable to the welder. I'm reluctant to modify the machine in any way substantially. At this time it's still a bit like a new car in the driveway. I'm even tempted to throw a coat of paste wax on it occasionally. (but i won't) I probably wouldn't even wish to get inside of it to put a relay across the switch itself. Tapping off the switch was the most modification I was comfortable with.
I really do wish to have them energize both with a single switch however, so I'll probably put some sort of multi pole knife switch on the wall behind the welder that will serve two separate boxes - a grounded 120 and the 240 that's there for the welder now. The welder/cooler will still be bolted together, just have two cords (dammittohell). I'll have to check with the manufacturer to see if it's ok to use remote power to regularly turn it off and on.
Sorry to all here if this has been a little too off diyaudio topic. I hope it's been at least a little interesting to some, and maybe even informative to others. I greatly appreciate the knowledge base in this community. I'd hate to abuse it.
you are getting 65VAC out of the transformer because you have the primary side hooked up to 120V. Once you connect the primary across the two hots (240V) you will get 120V out (2:1 turns ratio)
as for understanding how you get 240V across the two hots, think of it exactly as you would a typical transformer with a center tapped secondary, such as a toroid you find in an audio amp. you get some voltage V across the center tap and the top of the winding, and you get the same voltage V across the center tap and the bottom of the winding. however, from the top of the winding to the bottom of the winding, you get 2*V.
same exact thing with residential distribution. the pole pig is nothing more than a very large 120-0-120 transformer with a center tap secondary. the primary is connected to the high side (many kV) and it is stepped down to 120-0-120. the top of the winding is one hot leg, the bottom of the winding is the other hot leg, and the center tap is the neutral. this is why you see 120V between one hot leg and neutral and 240 (120 + 120) volts between both hot legs.
does this do anything for the elephant?
as for understanding how you get 240V across the two hots, think of it exactly as you would a typical transformer with a center tapped secondary, such as a toroid you find in an audio amp. you get some voltage V across the center tap and the top of the winding, and you get the same voltage V across the center tap and the bottom of the winding. however, from the top of the winding to the bottom of the winding, you get 2*V.
same exact thing with residential distribution. the pole pig is nothing more than a very large 120-0-120 transformer with a center tap secondary. the primary is connected to the high side (many kV) and it is stepped down to 120-0-120. the top of the winding is one hot leg, the bottom of the winding is the other hot leg, and the center tap is the neutral. this is why you see 120V between one hot leg and neutral and 240 (120 + 120) volts between both hot legs.
does this do anything for the elephant?
dammit i did it again!!!
You and I are just destined to clash here via misunderstanding aren't we gareth? I swear on my honor that I did not recall where I'd seen mention of "+120vac and -120vac". But following your last post I wondered and reread this thread. Honest gareth I'm sorry. I'm not challenging anyone here. I really do need to get the texts back out and put my basics back in order before I add any more unnecessary bulk to this thread. I'm very grateful for your help in explaining things thusfar.
And gain, yes that explanation does help.
I did connect the adapter to L1 and L2.
I measured 244vac across them. Got 65vac out of the adapter. Despite that explanation from the 'technician', a member of another electronics board is pretty convinced that that explanation has no merit whatsoever and that my adapter must be faulty.
You and I are just destined to clash here via misunderstanding aren't we gareth? I swear on my honor that I did not recall where I'd seen mention of "+120vac and -120vac". But following your last post I wondered and reread this thread. Honest gareth I'm sorry. I'm not challenging anyone here. I really do need to get the texts back out and put my basics back in order before I add any more unnecessary bulk to this thread. I'm very grateful for your help in explaining things thusfar.
And gain, yes that explanation does help.
I did connect the adapter to L1 and L2.
I measured 244vac across them. Got 65vac out of the adapter. Despite that explanation from the 'technician', a member of another electronics board is pretty convinced that that explanation has no merit whatsoever and that my adapter must be faulty.
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.