Came back and it was on fire...

[hoffman]

So I've been working on my newest tig cooler revision. I got a good pump, a bunch of fittings a psi gauge, radiator and a mystery muffin fan.

Well, I plumb it up and hook up all the 'lectric stuff and no leaks so I'm cool with it although It's still in the mock-up stage. While it's sitting there running on the bench I have to pee.

I just leave it running and go into the house to do my thing but when I return the damn thing is on fire...

Friggin' fan melted down. Oh well, I'll tackle it next week...

[Tinkerer]

Your lucky that you didn't burn yourself out of shop and home.

[aboard_epsilon]

what did you use .one them italian washing machine pumps ...

all the best.mark

[JRouche]

Glad you didnt have anything burn up....Fires can be dangerous...Maybe it was a 115v fan? JRouche

[hoffman]

It was a 115v fan but I wired it up to one leg of the 220 and ground. Could that have been what did it?

[CCWKen]

That didn't do it. It was probably all that 3-in-1 oil you were sqirting into it. http://bbs.homeshopmachinist.net//biggrin.gif

[winchman]

"It was a 115v fan but I wired it up to one leg of the 220 and ground."

Please tell us you really wire it up to one leg of the 220 and the NEUTRAL. You shouldn't use the ground as a return path.

I'm glad you didn't have a serious fire.

Roger

[hoffman]

Yea, I read that gasoline transfers heat better than water so I was running that as coolant. I'm glad I turned the pressure down from 250 to 100 psi...

[tattoomike68]

I could use a fan that shoots fire, I can use it as a heater in my shop.

Realy though, im glad olny the fan was on fire.

[.RC.]

<font face="Verdana, Arial" size="2">Originally posted by winchman:
Please tell us you really wire it up to one leg of the 220 and the NEUTRAL. You shouldn't use the ground as a return path.

</font>


Ground, Neutral and Earth are all the same with 3 phase power aren't they????? You have 4 pins...3 phase pins and a neutral while single phase you have active and neutral(which I guess have to swap around 50/60 times every second) and ground/earth...

[suprdvn]

"Please tell us you really wire it up to one leg of the 220 and the NEUTRAL. You shouldn't use the ground as a return path."

One of the reasons why you should not use ground: If the ground wire had a bad connection or became severed someplace before the breaker box then all metal hooked up to it would become electrified. Just touching a tool would give you a shock.

On a similar note, different legs of 120V should not be hooked up to the same neutral wire. Besides the potential of double the amperage on that neutral wire, should the wire become severed before the breaker box then all appliances plugged in would suddenly have 240 volts!

This happened to me. I knew better but made a mistake. The power was off for the wiring, turned power on, everything worked fine, bent wires into junction box, suddenly the basement lights became twice as bright!!! http://bbs.homeshopmachinist.net//eek.gif The water softener motor got real loud! I ran to the breaker box and shut off the main. It was too late for a microwave, got fried even though it was off at the time.
Uh, Mom, Dad, about your microwave... http://bbs.homeshopmachinist.net//redface.gif

[Swarf&Sparks]

"it was on fire when I lay down on it" http://bbs.homeshopmachinist.net//biggrin.gif

[J Tiers]

<font face="Verdana, Arial" size="2">Originally posted by suprdvn:
[B
On a similar note, different legs of 120V should not be hooked up to the same neutral wire. Besides the potential of double the amperage on that neutral wire, should the wire become severed before the breaker box then all appliances plugged in would suddenly have 240 volts!

[/B]</font>

Actually, that connection is perfectly OK per code, or was as of very recently. I don't have the latest copy. It has been commonly used for many years, particularly in kitchens.

AND, there IS only one neutral at the house entrance, (which BTW is THE ONLY place where it's connected (bonded) to ground). That single neutral goes out to the pole. So no matter what, you really only have one neutral wire for your whole house....

The neutral current won't be anywhere near doubled by having loads on circuits with a shared neutral, unless the power factor is way off of unity. This is because the two circuits are opposite phase (standard 220 1ph service).

If the power factor isn't unity, then there is a phase angle difference, and in that case neutral current calculation must consider phase also. It would have to be pretty bad to get close to double, though. Neutral current in bad cases is usually harmonics of the line, which means bad power factor.

OK, two 120V circuits. Call them circuit 1 and circuit 2, and assume for the moment that they share a neutral.

Say circuit 1 is drawing 10 A, and circuit 2 is drawing 5A. Any current on circuit 2 less than 10A will take current away from the neutral, because it is opposite in polarity.

So current will flow thru circuit 1 to the neutral, then 5A will flow onwards to circuit 2. The neutral gets the difference, and would have 5A flowing in it.

If both draw the same 10A in phase, there is zero neutral current.

If the neutral opens up in a one-neutral two hot system, the voltage will divide up according to the loads on each 120V line. If the loads were perfectly equal, the neutral would remain at zero volts, theoretically. (that won't happen in reality).

Whichever side draws more current will have less voltage, while the one drawing less will get more voltage... until it draws the same current as the other side..... whether that's good for it or not. This is one reason why a fuse or CB is never allowed in the neutral...

That white wire (neutral) kills more people than the hot wires do, because folks just don't understand it.

[hoffman]

I've been reading up on splitting the 220 like I did. Sort of a no-no...

I've got some proper 220v fans coming.

[Last Old Dog]

J Tiers, great explaination, well presented. How about you contributing another, addressing 'Balanced Load' whilst splitting legs for distribution through the facility? Eg: Lighting, small machinery and power tools, perhaps even dedicated circuts for sensitive electronics. Thanks
LOD