Open up your computer… look at the switching power supply unit… and then where it says D1, D2, D3, D4(should the bridge rectifer) find the trace coming out of these… this should be roughly 140 V Dc… if you touch it there you should get a jolt…
You could aslo buy an inverter… there are several types that can electrocute you
there is the 110V to 220V AC
There is the 110V AC to 110 AC
110vAC to 110 DC
also available for a 220V DC input or for 110 DC input
Actually it is possible to use a transformer to change 100 DC to 220DC. In fact most Power supplies do this
The trick is to run 140 V DC along a wire through the transfomer windings. located just before the tranformer connect a Power transistor to ground… have a clock pulse enter the base to switch the transistor on and off… the result being that the the 140 DC will ground when the transistor is switched on meaning the voltage in the tranformer will flcutuate between 140 V DC and O V… the rate it changes is dependant on the duration of the transistor being turned on and grounding the 140V Dc…
this fluctuation of the 140DC to 0V will cause a voltage in the secondary windings… then all you got to do is to rectify this again… the number of windings in the secondary in relation to the primary will make it a step up or step down…
This recitification and use of grounding is the preferred way to transform voltages as the common transfomer wastes 20 % of the energy on heat and noise
You can argue the physics behind what is happening in the elcetromganetic field in the transformer area of the Inverter… but essentially what is happening is that it is making a 110V AC a 220V AC by inverting and shifting the 110 V to make 220V
Back to the original quetion about 220V
110AC is the standard voltage in Taiwan… it enters your house and goes to the circuit breakers… here it is split with some cicruit breakers used for the lightening and others used for the wall plugs… on the other hand one line is fed into an inverter… although in Taiwan they probabily mostly used big heavy dirty transfomers… here is it converted to 220AC and is fed to the Air Con… the Air Con is grounded with a GND wire or should be and the return wire goes back to the Inverter to complete the circuit
Most dwellings in Taiwan have a 3 wire suppy. There is 110VAC between each of the 2 “outside” wires and the “middle” wire. There is 220V AC between the two “outside” wires. The maths is not that difficult.
The 2 “outside” wires provide 220V to your airconditioning outlets. One or other “outside” wire and the “middle” wire provide 110V to everything else in the house.
The middle wire should be connected to earth somewhere in you building.
I do not know what the regulations are, but it is normal practice and for safety. Earthing the middle wire should ensure that you never get a shock exceeding 110VAC. 110VAC is unlikely to kill you. Electric chairs typically use 2000V AC which results in about 7 amps flowing in the torso. A small part of that flows in the heart and that is how they die.
A transformer to supply an airconditioner would be about one quarter of the size of your airconditioner, and is therefore unlikely to be concealed in the wall.
A single-phase power supply consists of a “live” (fused) side, a return (which physically completes a circuit with the transmission equipment) and (optionally) a ground.
Three-phase supplies I understand too. I also understand how three phase supplies are stripped into single phase supplies for domestic use.
So where does this fantastic 2-phase power supply (delivered on 2 conductors no less) come from? Please somebody post me a URL to the relevant info on the web.
This is typical of US (and Taiwan) domestic distribution. )
So change the figures to 110V - 110V - 220V and you are there.
The pic is down the page a little - shows a 7200/240/120/120 transformer.
I cut a bit of the text for you
“There are two wires running out of the transformer and three wires running to the house. (not actually the way I would write it myself)
The two from the transformer are insulated, and the third one is bare. The bare wire is the ground wire. The two insulated wires each carry 120 volts, but they are 180 degrees out of phase so the difference between them is 240 volts. This arrangement allows a homeowner to use both 120-volt and 240-volt appliances. The transformer is wired in this sort of configuration:”
monkey - please do not take the cover of your switchboard - if you are young - ask questions - if you are older you should know that you are playing with something that you should not, and may never know about
Don’t worry rian, the cover will stay firmly on my switchboard … whatever one of those is. Didn’t bespectacled old ladies used to look after “switchboards” before the advent of digital telephone exchanges? “Connecting you now ma’am, [plugs huge jack into a hole barely visible through all the coiled cable].”
Isn’t the point though that the power company delivers 220V and 110V to each building? 220V isn’t “made” inside your apartment with a magic black box as Zhukov postulated.
And it’s completely wrong to refer to the 110V outputs from a center-tap arrangement as being two-phase. That is banal. Both 110V sources come from the same phase stripped off a 3-phase supply off the transmission grid. One phase is 180 degrees out of phase with the other because the polarity is inverted in the wiring … that’s all.
Have to wonder though, the common return (which is the center tap) will never be precisely 0V with reference to the 110V outputs. This coulld only happen when the load on both 110V circuits is identical.
Strapping the center-tap to ground, when it should be free to move with the load on the 110V circuits sounds like dangerous to me…
Maybe I should ask mommy to make me some lead underpants before I get bored with this and try nuclear fission experiments at home.
All voltage is relative - if you want to get into nuclear fission - please wait a moment while I move to another planet.
“Two phase” is a common way to describe a center taped transformer output, and reflects that the two available output voltages are 180 degrees apart in phase.
Yes there is 3 phases in the street at several thousand volts. Two of these phases are connected to each distribution transformer that has a single phase input (because the transformer has no knowledge of the other phase) and a 2 phase (single phase - center tapped - if you prefer) output in typical US and Taiwan practice. A transformer isolates the “relative” voltage.
An understanding of the square root of -1 may be necessary to further explain.
Responses in this thread remind me of many past situations with asian customers where the cost effective solution was not acceptable because it could not be found in a text book in their own language. The prize example was one case where, after $US150,000 of redesign,the customer suddenly became aware of a text book that confirmed our original design and accepted it (didn’t give us the $150,000 though).
I got an official reply from TaiPower (thank you!) and did some further studies on the subject:
TaiPower supplies a TT System consisting of 3 wires: L1 (Life/Phase 1), L2 (Life/Phase 2) and N (Neutral).
L1 against N and L2 against N give 110V while L1 against L2 gives 220V.
This is similar (equal) to the pic under the link provided by Rian (transformer with one winding tapped in the middle).
AC Voltage is used because you can carry it over long distances and transform it anyway you like, up or down. Long distance lines for example can carry in excess of several hundred kilovolts.
Grounding / Protective Earth (PE) must be supplied at the building and must not be connected to the N (as opposed to e.g. the German TN-C-S System where N and PE are to be connected).
According to my understanding there can’t be any phase difference or “magic box” between L1 and L2 as there is no 2x 110V “travelleing on one wire”. If L1 and L2 are not in phase they couldn’t add up to 220V.
Again this is opposed to the German 3 Phase System (220V or actually 230/240V now, measured by L1, L2 or L3 against N) where the phases are shifted by 120 degree, thus resulting in 380V (L against L) … in case you ever wondered how 3x 220 gives 380. Note they still use seperate wires.
PE must be connected if e.g. the equipment is inside a metal housing (like power supplies) and there is a risk of the life wire touching the housing in case of a fault.
The current usually passes through an ELCB/RCD (inside your distribution box) which compares the L vs the N, i.e. if the current “going” out is the same as “what comes back” it’s all fine.
Assuming now the L touches the metal housing and thus would provide a potential danger to humans the current is “absorbed” by the PE and guided to ground (GND).
The ELCB/RCD will not notice that there is less current on the N and thus disconnect the circuit completly. ELCB/RCD come in different ratings and are usually (at least) found in circuits supplying the bathrooms.
It is therefore advisable not to disconnect nor to use an adapter (3pin to 2pin) if the equipment is supplied with a 3 pin cord as you risk your own safety.
I am aware that most houses do not have 3 pin outlets but considering the possible consequences I would rather not connect it at all.
Is this the case in all dwellings ? There is no need then to bring a step up transformer to Taiwan to run 240VAC equipment, merely add the two single-phase supplies together ?
Incidentally, I was looking at the price of inverters the other day - an inverter to supply 240VAC at around 100A (what you would need to run a house on batteries) would be astronomical. Presuming you could find batteries big enough. And you can. Interesting point is that most System X telephone exchanges in the UK run off batteries. I know my local one does because I was in it when it was being built. The whole shebang is run off a DC supply, with generators kicking in to charge them during a power failure. Those are some big batteries. Now just to stretch the credulity somewhat, there is also a nuclear fallout shelter in my local exchange, which has a limited amount of valve and Strowger (mechanical switching) equipment in the basement.
Hexuan, did you ever see an electric wire made to transport 100A? Your calculation was based on car batteries (12V), right? Forget it! You wouldn’t need any lamps because the wires carrying 12V will glow by themselves. Actually, they might make your whole house glow, so its definitely not too dark there.
For smaller appliances, you can use a 12V car battery and an inverter, but don’t do that with anything consuming a bit more power. If you really want to go this way, put a few batteries in series to get a higher voltage - though you will probably only find inverters for up to 24V readily available.
Another way (if you have the money) would be a “frequency converter”. They are advertised in the electronic magazines here, on larger ones you can freely choose the output frequency.
But actually, all those things might not be necessary. Yes, the frequency here (60Hz) is different from Europe (50Hz), but only AC motors (like in washing mashines) will care for that fact - and even then the device still might run here. I wouldn’t worry now about the voltage, that can be easily dealt with, what is worth worrying is the (mostly not existing) grounding here…
Interesting point is that most System X telephone exchanges in the UK run off batteries.
This actually is my area of expertise but I must correct you: the exchange runs on DC power supplied by a rectifier system (SMR) which converts AC to DC. The batteries are there merely for backup purposes, i.e. in case said AC power supply fails and no generator kicks in (if available).
Depending on the size of the load / the power requirement you will indeed have some serious batteries there, or rather battery banks (several batteries connected together to add up the voltage and/or current as required).
BTW: Most telephone or mobile exchanges work on -48V DC. (Minus in front means the “plus” is connected to ground)
To generate 220V from 110V can easily be done using a step-up transformer (available at electronic shops) or inverters, the latter doing it electronically and are usually smaller in size. No batteries are needed.
If you are however looking at a load of 100A you do indeed need some serious transformer - and a second house to place it.
That said things here in Taiwan are easier as you can just ask an electrician to connect the two Life-Wires to your load (N is not needed, PE most likely or at least recommended) if it requires 220VAC. Check that the load can handle 60Hz.
Ah yes ! That’s right, of course. To a teenage boy “Rectifier” sounded a lot like “rectum”, and I had to see the things with my own eyes. Wandering around in an empty telephone exchange as it was being built was fascinating. The other thing that amazed me was the airconditioning system. Apparently the endless rows of switching equipment would all bust a bloodvessel if the temperature and humidity wasn’t absolutely right. The battery room was the best bit, though - like something out of 2001. And the room where the operators sat was like the bridge of the starship Enterprise.
Yes, the air-con system is very important as is the fire fighting system which is usually CO2 based.
Not really good for humans if you can’t get out of the room but the equipment won’t get damaged by the CO2.
In fact me and a collegue were inside a cabin (shelter) once when the CO2 was accidentally released but obviously we made it out in time.
That said my former company used to have a customer who actually installed a water based system in the switching room. Though nothing has happended so far it’s a very foolish move as you not only would loose the equipment but also service and by that your revenue. And rebuilding such an exchange would take weeks if not months.
Right, I am going to gingerly set foot back into this minefield. I have in the past successfully used a step up transorfmer to get 220V from Taiwan’s 110V supply. Now I notice the UK supply is 50 Hz and Taiwan’s is 60 Hz. What difference does that make ?
And while we’re at it - where does the earth wire from a domestic appliance go in Taiwan ? I take it that the earth connector in Taiwan is actually earthed somewhere or is in connected to the neutral of the incoming supply ?
I thought we all understood you can get 220V 60Hz from your Air Conditioner Outlet. It is not exactly 220V - just a nominal figure - most appliances will work fine in plus or minus 10 % (or more) from the lable voltage.
So for the 50 or 60 Hz - that is not so clear unless the lable says 50/60Hz. If not seek more advice. I will be happy to help if you want. Some 50Hz things work fine on 60 Hz - some may have problems.
I am about to buy one of those thin TV’s in China - the lable says 220V 50/60Hz - this means I can connect it to my Air Conditioner outlet if I bring it back to Taiwan (People who might say - what about NTSC/PAL/SECAM - yeah - I am aware of that too).
As for earthing - a few tests I have done about whether the “neutral” conductor is earthed in different peoples apartments have been inconclusive as to actual practice (yes it is supposed to be). Personally this probably due to “not know what and why” in a big way. I have found one side of the 220V earthed in a large apartment complex. (ie neurtal is 110V above earth). Another the neutral was fortuitiously high resistance earthed (this means the electrician made no efort to properly earth the neutral)