_____________________________________________________________________________ | File Name : XFMRS.ASC | Online Date : 11/22/94 | | Contributed by : Bert Pool | Dir Category : ENERGY | | From : KeelyNet BBS | DataLine : (214) 324-3501 | | KeelyNet * PO BOX 870716 * Mesquite, Texas * USA * 75187 | | A FREE Alternative Sciences BBS sponsored by Vanguard Sciences | |---------------------------------------------------------------------------| Power Transformers, How to Safely Connect and Use Them by Bert Pool Many of the experimenters on KeelyNet do work with Tesla coils, Lakhovsky MWO's, Rife generators, and some even do experiments with high voltage capacitive discharge explosion of water. Jerry Decker of KeelyNet asked me to write up a paper discussing the methods of connecting and using transformers, including the larger "pole pig" transformers. Because these transformers are dangerous high voltage, high power devices, I agreed that a paper discussing proper connections and safety needed to be written up. The purpose of this paper is not to induce you to try any of these things, but to point out specific dangers that you need to be aware of if you are contemplating lines of research using big transformers. Power transformers can be INCREDIBLY dangerous! _____________________________________________________________________________ *********************************************************************** *** Disclaimer *** I've tried to put information in here which is factual and of safety interest, but I don't guarantee anything! You are, I assume, an intelligent, thinking adult, and your actions are your responsibility, not mine. I assume NO liability. If you don't know what you are doing, then stay away from high voltage equipment. If you get electrocuted or kill somebody, or you burn off a hand, don't come crying to me! I'm trying to warn you with this paper; that this stuff is dangerous if you are not careful or if you don't know exactly what you are doing. It's rather like working with explosives or hand guns: if you know what you are doing, the danger is minimal. If you are careless or stupid, then someone, most likely yourself, can get badly hurt or killed. *********************************************************************** _____________________________________________________________________________ I begin this technical paper with a quote: *********************************************************************** "I'm more careful when working on big transformers than just about anything else I do, because I know that I probably won't survive making a mistake." - Quote by me, in one of my more lucid moments. *********************************************************************** If you are a novice, stay away from distribution transformers! Neon transformers will hurt you - distribution transformers will kill you. Violently..... _____________________________________________________________________________ Neon Transformers Using the smaller neon transformers is relatively safe, compared to the large potential and distribution transformers. Most neon transformers range in voltage outputs from 7,000 volts to 15,000 volts. Output current can range from about 5 milliamps (.005 amperes) to 60 milliamps (.060 amps), and you can occasionally find a rare 120 m.a. transformer. Neon transformers can deliver a very nasty shock, and can cause painful burns, and under proper circumstances can even be lethal. _____________________________________________________________________________ **** Warning ***** A neon transformer's output CAN be lethal if the current path travels through the heart, i.e., if you were to touch a transformer's two terminals with both hands (or one terminal and ground). It only takes a small current of 20 to 30 milliamps to cause the heart to go into ventricular fibrillation - a condition where the heart no longer pumps blood rhythmically, but just sits and quivers like a mass of jello. Once the heart goes into ventricular fibrillation, a medical defibrillator must quickly be applied to the victim's chest to try and re-start the heart's natural beats. De-fib units work by passing a pulse of high voltage, high current through the thoratic cavity, causing the heart to contract into a hard ball. If a victim is lucky, his heart may start beating again. Then you worry about whether he will be a vegetable because of oxygen deprivation to the brain during the time the paramedics were enroute..... CPR can be a life saver in these situations. If you are going to work with power transformers I HIGHLY suggest you and your assistant(s) need some real CPR training. Contact your local Red Cross office for their scheduled classes. So, rule #1 - KEEP ONE HAND BEHIND YOUR BACK WHEN WORKING ON HIGH VOLTAGE EQUIPMENT. _____________________________________________________________________________ Sounds dumb, right? Well, Nikola Tesla himself rigorously followed this rule, and I learned it years ago in school while working on the high voltage section of color television receivers (27,000 volts). You are much more likely to survive touching a high voltage current with only one hand - the current will most likely travel down one side of the body and bypass the heart. And, if you are wearing thick rubber-soled shoes you are even less likly to be injured or killed! _____________________________________________________________________________ Neon transformers Used neon transformers may be found at neon sign shops, salvage yards, etc. 9,000 to 15,000 volt units usually can be had for $30 to $35. New transformers start at about $100. The tar insulation used in neon transformers carbonizes with age, and old transformers do not hold up as well as new transformers when connected to Tesla coil circuits. You may carefully remove the metal case and tar on old neon transformers, and the exposed transformers will be much more reliable in Tesla coil circuits. Be very careful not to cut or break the very fine wire used in the secondaries if you disassemble a neon transformer. This wire can be smaller in diameter than a human hair. _____________________________________________________________________________ Connecting neon transformers together Neon transformers almost always have an input of 115 volts, and output voltages of several thousand volts. The case of the transformer is grounded. What is very important to understand is that the secondary winding is a center-tapped winding, and the center tap is connected directly to the case (and laminated iron core) of the transformer. This means that if you have a 12,000 volt transformer, you have 12,000 volts between the two high voltage insulators, and you also have 6,000 volts measured from the case to either high voltage connection! You can connect neon transformers in parallel, but you CANNOT connect them in series! _____________________________________________________________________________ **** Very important safety warning! ******* Do NOT connect neon transformers in series! If you try to connect neon transformers in series to get a higher combined voltage, you will be placing several thousand volts on the cases of the transformers. The high voltage will most likely arc to the 115 volt terminals, causing a disastrous short. You will also create a very, very dangerous safety condition with the cases being energized! Do NOT connect neon transformers in series! Neon transformers CAN be connected in parallel for more CURRENT. The voltage will remain the same. If you have two 12,000 volt transformers rated at 30 milliamps and parallel them, the current available is now 60 milliamps. It is very important to make sure the transformers are rated at the same voltage, and preferably the same current. If you connect two neon transformers in parallel, and they have different voltage ratings, one or both transformers will almost certainly be destroyed (especially if connected to a Tesla coil. I know, I've tried it.) You need to know that neon transformers are self-limiting in the amount of current they can supply. You can actually short out the two high voltage connections of a neon transformer with a wire and then plug in the transformer and nothing violent will happen! Neon transformers have a built-in feature which limits the power available to the secondary winding. Still, it is not a good idea to short out these transformers for extended lengths of time. Some neon transformers can have this current limiting feature bypassed to extract more power - this is covered in a later section. _____________________________________________________________________________ Connecting transformers in parallel How do you connect two neon transformers in parallel for more current? First, number the 115 volt input connections on each transformer #1, and #2. Next, number the high voltage output connections #3, and #4 on each transformer. Connect #1 to #1, #2 to #2, #3 to #3, and #4 to #4. Run wires from the two high voltage terminals (3 & 4) to a spark gap (a spark gap is simply two wires placed about 1/4 inch apart). Connect 115 volts to 1 & 2. A beautiful flame-type arc should immediately jump across the spark gap. If this does not happen, then the two transformers have been connected "out of phase". Should you do this, simply disconnect power, and swap the wires going to 1 & 2 on ONE of the transformers (not both!). Re-connect power, and you should see the high voltage jump across the spark gap. You may parallel additional transformers, connecting them one at a time, and testing to make sure you get the polarity of 1 & 2 correct each time. I have connected six neon transformers in parallel, and a friend of mine once had twelve transformers paralleled for a really big Tesla coil! _____________________________________________________________________________ Bypassing current shunts Some larger neon transformers have special laminations which are located in the core, between the primary and secondary windings. These laminations are at right angles to the core laminations, and these "sideways" laminations may be driven out of the transformer core with a hammer and a small block of wood. You will find that the amount of current available to the secondary will be much greater once you do this. You should be careful to not short out a transformer's secondary windings after you have performed this modification, since you have removed part of the current limiting feature. One Tesla coil builder in Dallas, David Chapa, has a Tesla coil which puts out 48 inch+ discharges using ONE 15,000 volt, 60 ma neon transformer with this modification! _____________________________________________________________________________ **** Neon transformers with current shunts removed are much more dangerous than shunt protected transformers - use caution! _____________________________________________________________________________ Potential and distribution transformers For our purposes, watts and kva (kilovolt*amps) are the same thing. Whenever I say this, engineers will always jump to their feet and start shouting things about reactances and inductances and phases and impedances, but the fact is that in 99 out of 100 cases, experimenters can either use the term "kilowatts" or they can use the term "kva" and the transformer will never know the difference. If you are going to use a potential transformer for a Tesla coil, or other similar intermittent duty application, you can push the transformer to twice or even three times its specification plate power rating safely. This means that you can operate a 5 kva transformer at 10 kva for short periods of time, with time-outs to allow the core and windings to cool down. Be aware that you will NOT get the same performance out of a 5 kva transformer pushed to 10 kva as you will from a 10 kva transformer running at its rated 10 kva! Larger transformers use heavier wire, and peak or instantaneous currents will always be larger in the bigger transformers. A Tesla coil using a 10 kva transformer, running at 10 kva will always outperform a 5 kva transformer pushed to 10 kva. More instantaneous power is always available from the larger transformer. Main point: you can get a lot more power out of a transformer than the spec plate shows. Potential transformers usually can be found in old Ham radio transmitters, r.f. induction heating units, microwave ovens, radar transmitters, etc. Output voltage ratings can run from a few hundred to several thousand volts. Current available in the secondary windings is always much higher than in neon transformers. _____________________________________________________________________________ ***** Lethality Warning! ****** *** Death, Doom and Destruction! ******** Potential transformers are MUCH more dangerous to work with than neon transformers, since the current is higher and more likely to cause serious physical damage. A neon transformer will cause a nasty shock and a mild burn. A large potential or distribution transformer can burn off an entire arm or leg! Large potential transformers will literally cook you; it can make the blood in your body boil and explode. YOU ABSOLUTELY MUST BE CAREFUL AT ALL TIMES WHEN WORKING WITH POTENTIAL AND DISTRIBUTION TRANSFORMERS! NEVER WORK ON POTENTIAL/DISTRIBUTION TRANSFORMERS ALONE - ALWAYS HAVE SOMEONE WATCHING YOU IN CASE SOMETHING GOES WRONG. USE RUBBER MATS ON THE FLOOR. USE HIGH VOLTAGE RUBBER GLOVES. USE COMMON SENSE! _____________________________________________________________________________ Potential transformers are not self-limiting in current. What does this mean in real life? If you were to take a large potential transformer, say like out of a large radar transmitter, or a distribution transformer (pole pig) and if you connect it to your electrical outlet in your lab, it will probably just sit there and produce a lot of high voltage as it quietly hums. If you measure the current flowing in the transformer's primary, it will be a piddly three or four amps. UNTIL you connect it to a load! If you try to connect the high voltage to a spark gap, or to a Tesla coil, you will hear a violent hum, the lights will dim, and you will instantly blow the circuit breakers in your power panel. Guaranteed! Think about it for a minute. A standard pole pig is designed to step DOWN 12,400 volts to 120 and 220 volts, to run your house, and two or three of your neighbors' houses. The typical house uses 110 and 220 volts, usually up to a couple hundred amps. Combine the power usage of four houses, and the transformer has to supply 220 volts at maybe 800 amps. That's a LOT of amps! We experimenters usually connect these monster transformers BACKWARDS, putting in 120 or 220 volts so we can get out 12,400 volts to run our Tesla coils and other nefarious devices. Guess how many amps that transformer is going to want to pull from the 220 volt line so that it can deliver that 12,400 volts at its rated current? Right! It will want to pull 800 amps. Most of us are not going to be able to supply 220 volts at 800 amps - and indeed, we don't WANT to! We have to limit the current to something reasonable - maybe 20 or 50 or 100 amps. We do this by placing a current limiting device in series with the primary of the transformer. _____________________________________________________________________________ Limiting current and power How do you limit the current in the primary circuit? By placing either a resistor or an inductor (coil) or a variable transformer (variac) in series with the primary of the transformer, or a combination of these. Large potential/distribution transformers are rated at several thousand watts. The resistor or inductor or variac that you use with a transformer of this type must be capable of handling the maximum rated power you intend to work with. If you have a 5,000 watt transformer (5 kva), then you're going to need to limit the power available to the transformer to 5 kva or less, and your limiting device must be capable of handling this same amount of power! You may be asking yourself, where am I going to get a 5,000 watt resistor? You can use heating elements out of electric heaters and ovens, and even electric water heater elements (which cost aboust $7). When using variacs, remember that you cannot use a 500 watt variac to control a 5,000 watt transformer, unless you expect to limit the transformer's power to 500 watts or less. If you have a 5 kva transformer, and you expect to push it near 5 kva, then you will need variacs rated near 5 kva. 220 volt variacs would need to be rated at 20 to 30 amps. Remember that variacs too, can be pushed beyond their rated output in watts, but only for short lengths of time. You are best off here using variacs rated near the power level you expect to work at. You will get into trouble using variacs too small or too large! Too small, and the windings will fry. Too large and you cannot limit the current adequately. For example, it is not a good idea to use 10 kva variacs to control the current going to, say, a 1 kva transformer. Why? The internal resistance of the variac will be so low that you may not be able to limit current to a controllable level. Most big Tesla coils use a combination of two variacs in series to control power to the potential transformer. One variac is used as a giant current limiting inductor, and the other variac is used to vary voltage. You may also take a Lincoln arc welder, short the output leads (the low voltage side), and connect the 115 or 220 volt side of the welder in series with your variac and potential transformer. The potential transformer cannot receive more current than can pass through the primary of the welder. You may even use the current settings on the welder to pre-select different current settings (the higher the current setting, the more power will flow through the primary circuit). Let us say that under full load, your welder will pull 25 amps, max on the primary (220 volt) side. Placing it in series with your potential transformer guarantees that the transformer cannot pull more than 25 amps either! I've even used a 3,000 watt clothes dryer in series with a transformer to act as a current limiter! As I mentioned earlier, most large Tesla coil controllers use two variacs in series to control the voltage and current going to a potential transformer. You do, however, want to make sure that you don't adjust the current limiting variac for too few turns, or the windings will burn. Start out so that your current limiting variac has current going through the maximum number of turns. Turn your "voltage" adjusting variac up and see what how your potential transformer performs. Turn the voltage down, and adjust the current limiting variac so that there are a few less turns and increase your voltage again. Repeat this procedure until operation is optimal. You want just enough of an inductance in the current limiting variac so that magnetic saturation occurs at just the desired power level. You may also place high power, low resistance heating elements in series with the variac(s) and/or other inductive current limiters. Appliance repair centers usually have the heating elements in stock. You may use the "exposed coil" type of element, and place sliding taps on the coiled nichrome wire element and precisely adjust the resistance of the element. You may also parallel heating elements to allow more current to flow through the circuit. For example, if you place a 1,000 watt heating element in series with a potential transformer, you've just guaranteed that no more than 1,000 watts of power can flow through the primary of the transformer. If you place a second 1,000 watt element across (in parallel) with the first heating element, you allow a maximum of 2,000 watts of power to flow through the primary of the transformer, etc.. One note on using heating elements to limit current: a heating element has a lower resistance when it is cold than when it is hot. You will start out with a lot of current, and as the element gets hot, the current will drop. This is why heating elements are seldom used by themselves to limit current. Usually a very large wattage element is used in series with one or two variacs. Do I need to remind you if you run power through a heating element it will get hot? (duuuuuhhh?????) Make sure you mount the electric heating elements so that the heat produced doesn't burn anything. A final way to adjust the current is to use a variac to control voltage, and an electrolytic resistor element to limit the current. An electrolytic resistor can be made from two stainless steel plates, about one foot square, immersed in an insulated container filled with a mixture of water and bicarbonate of soda. Build your electrolytic resistor by taking a plastic trash can, set it on a plexiglass plate or rubber pad, and fill it 2/3 full with warm water. Mix in bicarbonate of soda until the mixture saturates (the soda stops dissolving and starts to accumulate on the bottom of the tub). Your two stainless steel plates are placed in the solution a few inches apart. You will control current by raising and lowering the plates into the solution. The more of the plate surface which is in the solution, the more current that can flow between the two plates. This variable resistor is connected in SERIES with your control variacs to limit current. Make sure the control rods which raise and lower the plates are insulated! You may even use a reversible geared motor with a worm drive to operate the control rods. During operation, the water will get hot. Do not operate the electrolytic resistor for extended runs, or the water may boil. _____________________________________________________________________________ ******** WARNING #1 ******** DO NOT USE SALT WATER AS THE ELECTROLYTIC SOLUTION!!!!! DURING ELECTROLYSIS, THE NaCl (SODIUM CHLORIDE) IN THE WATER WILL DECOMPOSE AND RELEASE LARGE QUANTITIES OF CHLORINE GAS WHICH IS VERY POISONOUS! EVEN SMALL AMOUNTS OF CHLORINE CAN CAUSE SERIOUS BURNS TO THE LUNGS. USE BICARBONATE OF SODA, NOT SALT. ********* WARNING #2 ******** ELECTROLYSIS WILL ALWAYS RELEASE OXYGEN AND HYDROGEN GAS, WHICH FORM A VERY EXPLOSIVE MIXTURE, IF CONFINED. MAKE SURE YOUR ELECTROLYTIC RESISTOR IS VERY WELL VENTILATED! _____________________________________________________________________________ A word about capacitors Many circuits involving power transformers also involve capacitors. Capacitors can store appreciable quantities of electrical power. High voltage capacitors can hold enough of a residual charge to cause a violent muscle contraction, and large capacitors can even deliver enough charge to kill you. Always discharge a capacitor with a discharge tool (a high wattage, 250k ohm resistor with well-insulated leads works well) before servicing capacitors. Most Tesla coil designs will self-discharge capacitors through the power transformer when power is turned off. There is an exception, however! Some Tesla coils designs use TWO capacitors in a "balanced driver" configuration. The nature of this design is such that the caps can retain a charge even after power has been disconnected. Rule #2: always discharge capacitors before handling them. I'd like to finish this paper by making some final comments on safety: 1) I always stand on rubber mats to insulate me from ground. 2) I keep one hand behind me when making adjustments on high voltage equipment. 3) I have an observer on hand who knows CPR. 4) I keep a cordless phone handy in case of emergency. 5) I keep a fire extinguisher nearby - remember, pole pigs are filled with flammable oil! 6) I use indicator lights to show when power is on. 7) I always disconnect power at both the circuit mains and at the on/off switch to insure that the circuit is DEAD, so I won't be, before working on circuits powered by high voltage transformers. And I repeat the quote: ***************************************************************** "I'm more careful when working on big transformers than just about anything else I do, because I know that I probably won't survive making a mistake." ***************************************************************** Distribution transformers will burn off arms and legs and kill you. It's not a pretty way to die. Be super careful! Informational note: Interested researchers may obtain invaluable information on high voltage equipment, specifically Tesla coil related, from the Tesla Coil Builders Of Richmond (VA). Richard Hull is one of the mainstays of this excellent group of researchers. Dozens of 2 hour videos are available on the proper ways to test, rebuild, and connect transformers and capacitors of all sizes, and using them in Tesla coils to produce voltages as high as several million volts. Distribution and potential transformers beyond 10 kva are sometimes used, and man-made lightning 13 feet long (and more) is produced from large Tesla coils and shown. Safe operation is always stressed. Ask for a catalog of available video tapes and books. The address for this info is: Richard Hull TCBOR 7103 Hermitage Rd Richmond VA 23338 _____________________________________________________________________________ Vanguard Note A Superb Paper! Very well written, humorous as well as being highly informative and safety conscious. The 2.3 million volt Tesla Coil we used in our shows are posted on KeelyNet as ZAP1, ZAP2 and ZAP3.GIF. We no longer have this coil since it was leased for experimental and show purposes. The system as pictured had a single variac, feeding a pole pig, running off 220VAC. The pole pig fed a rotating tungsten spark gap which fed the primary. The coil was tuned to 170kHZ. For safety purposes, a dead man switch (had to be held closed manually to keep power flowing) was used and controlled by the operator. Since we ran the high voltage over the body, we took the least chances we could for shocks. Only one time was anyone ever 'tingled' and that was me when I was doing our ZAP show. I leaned over too far toward the audience and a bolt that I was shooting off my fingers, arced around to one of the lightning rods....I disengaged, but it was quite a shock at around 900,000 volts. Curious events we noticed during our Tesla coil operation... A digital watch still ran fine after being accidentally left on during the show in which part of the routine was to allow 900,000 VDC to run over the body. During one demonstration with all the theater lights turned off, I was watching the streamers shoot off my fingers and saw small golden yellow spheres that were about the size of glowing BBs. They were randomly shooting from the skin into the bright blue plasma stream and could not be seen by Ron or Chuck from the necessary safe distance to keep from being hit with a bolt. We did not know what to make of them. The effect ONLY OCCURRED around 850KVDC or greater. We tried to photograph the spheres, but could never get a good clean shot because of the distance. The bolts averaged around 3 to 6 feet at 900,000 depending on humidity and other conditions. After much puzzlement, we came to the conclusion that the spheres must be glowing sodium, since salt had been sprayed on the metal plate on which I stood barefoot. To test this hypothesis, we made absolutely sure there was no outside salt introduced and the upper body, arms, hands and props were all cleaned with pure water. The glowing spheres still appeared. The other idea was that it was cell salts containing sulphur since they glowed yellow. It is a known phenomenon that high voltage streaming off the body in this manner can electrify and carry matter with it. Perhaps it was dead skin cells. The funniest thing we saw was one time when Ron Barker stood on the metal plate (5 feet off the floor). You had to wet your feet with salt water to increase conductivity, then spray your head and hair with distilled water to keep it from catching on fire. Ron did not get his head wet enough and so he was waving his hands around as Chuck increased the power to about 800,000 VDC. Since high voltage streams most easily off of pointed structures, the fingers are the 'logical' emitter. However, I have shot it off my knuckles, elbows, nose and tongue....they wouldn't let me do the experiment I wanted to do....what a picture that would make! Anyway, as Ron moved his hands downward, the top of his head was not wet enough and we noticed a major series of bolts shoot out of the crown of his head. At the time, we imagined we heard a thwump as a chunk of hair got blown off, but we got him down and he was all right. Nothing really dangerous, just that it was so unexpected. When the plasma is streaming at full velocity, it does cause burns and blackened holes in the skin. We really wanted to duplicate Dr. Nelsons picture as in HARDY1.GIF on KeelyNet but using a 2 million volt pyramid instead of the 100,000 volts he used. If Mary and Dean Hardy are correct in their idea that such an arrangement generates a double helix beacon that is detectable by ET's who then come to investigate, we should get a mother ship with a 2 million volt coil. We never did get a chance to set up that experiment because we were so dog tired from working our 40 hour real time jobs, then doing the lighting shows, 3 per day (Mon-Fri) and 5 on Sat and Sun. It will definitely be something we want to do at the State Fair of Texas when we hit the lotto.... Don't read this wrong, we aren't all crazy, just that if you don't try new things, you will end up saying, "I could have....". As Bert points out, if you decide to do any experimenting with high voltage, be extremely careful. Good luck...>>> Jerry _____________________________________________________________________________