Transformer with dual primaries

shortbus

Joined Sep 30, 2009
7,091
For reasons I am not so clear on is when you just switch the "hot" and leave the neutral hooked up it will build up stored energy, then when that switch is flipped it discharges or de-energizes.
Can you elaborate on this? NEC says neutral isn't to be switched. "You wire a switch to make or break the supply conductor-also called the hot lead. The NEC specifically bars switching the grounded (neutral) conductor or the grounding conductor [404.2(B)" From - https://www.mikeholt.com/mojonewsarchive/NEC-HTML/HTML/Article-404-Switches~20040624.php
 

crutschow

Joined Mar 14, 2008
23,544
just switch the "hot" and leave the neutral hooked up it will build up stored energy
Not true.
Switching on not switching the neutral along with the hot has no effect on any "built up stored energy" whatever that is.
Whether windings are in series or parallel also has nothing to do with any current surges as long as the applied voltage is not higher than the transformer rating.

The are two common reasons for blow fuses or breakers when energizing a transformer.
One is if there is a rectifier on the output with a large filter capacitor, which causes a high inrush current to charge the capacitor.
The other is the high initial magnetizing current pulse that can occur if the transformer happens to be energized near the positive peak of the sinewave.
 

crutschow

Joined Mar 14, 2008
23,544
I kind of figured It would go this route. Yes it is true. I have a hammond transformer that will do this unless the Hot and neutral is switched. However one way or another I had this problem; someone on another form explained what was happening and told me to switch both hot and neutral and then the power supply never had problems with blowing fuses or tripping the breaker.
Sorry, but that's complete nonsense.
You cannot get power from only one wire.
Whether the neutral is connected on or not makes no difference to the circuit, unless you have figured out a way to break a fundamental law of physics. :rolleyes:
 

#12

Joined Nov 30, 2010
18,160
On a off note here,
In another off-note, you are hijacking this Thread and doing no service for the Thread Starter.
If I was a Moderator, I would give you your own Thread to examine these myths.
For now, I suggest you do that for yourself.
 

RichardO

Joined May 4, 2013
2,268
Yes it is true. I have a hammond transformer that will do this unless the Hot and neutral is switched. However one way or another I had this problem; someone on another form explained what was happening and told me to switch both hot and neutral and then the power supply never had problems with blowing fuses or tripping the breaker.
Not true.The are two common reasons for blow fuses or breakers when energizing a transformer.
One is if there is a rectifier on the output with a large filter capacitor, which causes a high inrush current to charge the capacitor.
The other is the high initial magnetizing current pulse that can occur if the transformer happens to be energized near the positive peak of the sinewave.
Maybe we need to consider a third -- a winding shorted to the core?
 

ian field

Joined Oct 27, 2012
6,539
On a off note here, when you have a transformer with dual primaries and dual secondaries; if you have primary coils wired parallel and the secondary coils wired in series (plus the rectifier and reservoir capacitors) you may experience problems with it blowing fuses and popping breaker. For reasons I am not so clear on is when you just switch the "hot" and leave the neutral hooked up it will build up stored energy, then when that switch is flipped it discharges or de-energizes. If you have problems with this you will need to switch both the hot and neutral. I had this problem till I found some information on another form. You can also add resistors (a load, parallel) on the primary winding, secondary windings, and from rail to rail and rails to ground etc

I am sure there is someone who could explain this, but it sure is not me!
The only use I can think of for dual primaries is; universal mains transformers - they had 2 identical primaries that you wire in parallel for 110V and series for 220V.

Correct phasing is important - wrong phase in series just won't work, wrong phase in parallel blows the fuse and/or lets the magic smoke out of the transformer.
 

shortbus

Joined Sep 30, 2009
7,091
NEC also says it is ok to use water pipes for ground???
So your saying miles and miles of underground water pipe is not sufficient? What would you consider a good ground to be?

I think they are referring to safety ground which is not the neutral wire. Also In computers and audio equipment they switch both contacts almost always. Mainly because it is able to be both 120v and 240v. I get a lot of double pole switches out of computer power supplies.
You do know that 220V uses two hot wires don't you? And that computer power supplies are switch mode supplies, don't you?

You will just have to assume I am making all this up and that I am a liar or crazy.
There is a third reason. You don't understand how AC electricity works.
 

MrChips

Joined Oct 2, 2009
19,426
Ok let's make it simple! Ask any musician with no knowledge of electronics, if they cut the ground from there guitar to there amp can they still hear there guitar in there amp.
If I cut the ground in my cable I hear a loud hum and it is not coming from my guitar.

Then prove that you cannot transmit an ac signal across one wire.
I can transmit AC with zero wire.
This proves nothing about how AC works.
 

MrChips

Joined Oct 2, 2009
19,426
I am going to intentionally drag this out and see what someone best proof against my claims are. I am telling you all disprove me with science. Get out your bread boards, text books, reference material, calculators etc. I encourage you to try and duplicate my claims or disprove them!
Are you an Internet troll?
 

MrChips

Joined Oct 2, 2009
19,426
with 56 posts I don't think so.

A drill instructor would create ridiculous and seemingly impossible tasks and not give me any answers, in order to teach me to go an find a solution to problems. When people ignorantly try to insult you and are critical or you, then you simply give them no answers; for you have not found a friend but an enemy. I do this out of principal. I know there are some smart people here but they don't know everything. I want to test there science.
If that's what you want to do. Just remember

 

djsfantasi

Joined Apr 11, 2010
5,704
Sure accidentally touch only the hot wire and what happens? Sure accidentally lick the neutral and what happens?

Yes you can use the hot if you phase shift the signal then hook it up to the other prong? Opposites attract? However the filter or network will have to be able to react to the total amount of power the load desires or there will be a voltage drop. In other word split the wire into two signals hook one end up to a low pass and the other to a high pass filter, tie the outputs of the filters together to get your sum of the phase shift networks. You can then insert a load in series between the networks or tap in the center of the networks and the unmodified signal. However it is less cost effective to transmit power this way.
Mods, please split this nonsense into its own thread. It doesn't appear to break any of the TOS, but is nonsensical. As such however, the TS challenge may prove to have entertainment value.

@Ripplenwinder please post a circuit providing power over one wire by phase shifting the original signal. I believe you have said that you have done so. We would like to see how
 

R!f@@

Joined Apr 2, 2009
9,682
OP is confusing mains voltage with differential (XLR) audio signals.
I think he did tests on XLR audio signals and assume the same can be done with 220V 50Hz main's voltage

by the way I can touch or even lick the Neutral wire in my workshop but I will NOT TOUCH the live as I know where I might end up. But this does not prove the power is transmitted thru one wire. Phase shift or not.

An XLR audio signal will work with disconnected ground provided that the wire is not long. If too long it WILL pick up noise..Period.

I do not need to do tests on these things to find out. I am doing the same things for living.
I don't care what OP says. He wants us to believe then he has to prove it. If he doesn't he is lying or mistaken
 
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DickCappels

Joined Aug 21, 2008
5,952
You are welcome to ignore posts that attempt to hijack threads. He has been asked to open his own thread. If he repeats, please report again.
 
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