FlybacK Transformers
FlybacK Transformers
Can flyback transformers be Paralled to produce higher voltages?
Does anyone have a driver circit for a black and white flyback I recently purchased surplus flybacks with 5 pins on the primary side, I am currently trying to find the schematic for them online.
Does anyone have a driver circit for a black and white flyback I recently purchased surplus flybacks with 5 pins on the primary side, I am currently trying to find the schematic for them online.
- Richard Hull
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Re: FlybacK Transformers
No. Flybacks can't be paralleled or really, effectively, series connected for higher voltages.
Normally one would series connect for higher voltages. Unfortunately in the transformer world, this would demand some dangerous floating deck power assemblies. It could be done and has been done in heroic circumstances. It is always much more trouble than it is worth in the engineering world. For one-off arrangments, it can sustain.
Richard Hull
Normally one would series connect for higher voltages. Unfortunately in the transformer world, this would demand some dangerous floating deck power assemblies. It could be done and has been done in heroic circumstances. It is always much more trouble than it is worth in the engineering world. For one-off arrangments, it can sustain.
Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
Re: FlybacK Transformers
Thanks for the input. Do you know of any schematics to assemble a power supply to drive the primary's on a 5 pin flyback.
FYI I found an intersting web site of optics and electronic's called the s urplus shed. www.surplusshed.com
FYI I found an intersting web site of optics and electronic's called the s urplus shed. www.surplusshed.com
- Richard Hull
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Re: FlybacK Transformers
I have no schematics but there was one in a recent Nuts and Volts magazine specifically to drive old B&W TV flybacks. I have thrown it out now.
Richard Hull
Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
Re: FlybacK Transformers
here is a bit of useful info on driving the b/w flyback transformers. usually, it is easier to wind your own primary(ies) than to decipher the factory pin out. you usually only need a few turns for a primary...
http://www.powerlabs.org/flybackdriver.htm
this isn't the best circuit, but it has always worked well for me (and it is super simple).
Q
http://www.powerlabs.org/flybackdriver.htm
this isn't the best circuit, but it has always worked well for me (and it is super simple).
Q
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Re: FlybacK Transformers
The circuit shown at the site Q mentioned uses the flyback as part of a really simple blocking oscilator. This is easy, but it will severely limit the amount of power that can be delivered, as the drive to the transistor is lousy and slow, If you try to rectify the output, the power delivery will be limited to a few tens of watts at most. I posted a circuit a while back in files that is more complex, but with some rectification it may be suitable for lighting up a demo fusor given proper resistive ballasting. BTW, the transformer shown in the demo-pictures is an old style flyback the preferred style for impromptu modifications, as there is most times a lot more room on the core to add new windings without having to monkey around with the old ones. You know that you have a really old flyback when you see a one-turn loop of HV wire for driving the filament of a 1K3 or 1K3 vacuum tube rectifier.
- Richard Hull
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Re: FlybacK Transformers
You really should endeavor to obtain a modern flyback for simple HV work. They are sort of ready to go. You could just drive one with Richard's circuit or a pulsed IGBT and you get "ready to use" DC out. I often add about 2000pf of extra doorknob capacitance to the output lead of the flyback to ground to boost the reserve capacity. These are suitable for all manner of electrostatic motors and experiments. You would need a really large 36" color set sized flyback to get much over a couple of milliamps out of it. Old B&W flybacks were not real well insulated as few, if any, of those sets reached 20KV. Some modern, large, color TV's need up to 30kv or more on the anode. This makes their flybacks much more desirable for the real high voltage nut.
Richard Hull
Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
- Mike Veldman
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Re: FlybacK Transformers
I've played with a bunch of different flybacks, I too am a "high voltage nut." The sealed ones are not too tough to drive. The primary windings are very similar on most I have messed with. There will be a primary drive winding, sometimes a feedback winding, a yoke drive winding and sometimes also a low voltage power supply winding used to generate voltage for the low voltage circuitry. Usually, not always but usually pins 1 and 2 are the primary. I generally just use an ohmmeter and determine the high voltage windings and the primary. The primary will most likely be designed to operate, depending on the make, up to near 150vdc. The winding usually will ohm out in the .8 to 1.2 ohm range, approximately, more or less, kind of. Take a reading on a filament transformer and find a winding similar. I generally make up a 555 oscillator to run in the 15 to 20 khz frequency range and capacitivly drive a television horizontal output transistor. As a rule I place the transistor in the ground leg of the primary and run a power supply that is variable on the other leg. The primary will draw a couple of amps easily. Triplers are pretty neat for upping the voltage and making high voltage metering circuit out of, if you have any of those. They are sometimes built into the flyback. The triplers I've played with are not very tolerent of input voltages above about 12kv, they tend to suffer insulation breakdown.
Sorry this is not a very specific tutorial, but hopefully it's enough to get you started. I've never tried putting flybacks in series or parallel for more current or voltage. I have run some under oil for increased insulation before I destroyed them, as well as having pulsed some to death, flybacks are not very forgiving. I have come across some higher current flybacks for radar display use, so you might look for those.
mike
Sorry this is not a very specific tutorial, but hopefully it's enough to get you started. I've never tried putting flybacks in series or parallel for more current or voltage. I have run some under oil for increased insulation before I destroyed them, as well as having pulsed some to death, flybacks are not very forgiving. I have come across some higher current flybacks for radar display use, so you might look for those.
mike
I tried to contain myself, but I escaped.
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Re: FlybacK Transformers
I kinda beg to differ about modern flybacks being "ready to go". They are optimized to run as flyback transformers, meaning that the energy transferred to the secondary is first stored in the core. This is fine and dandy for their avowed purpose, but if you want to get more than a few tens of watts out of them, you need to ditch the origninal primary winding, remove most or all of the core gapping material, and drive the secondary using a push-pull primary. A large, properly arranged flyback modified in this manner should be capable of 100-150W, though it will need a multiplier on the output. This is good enough to be able to light up a small demo fusor. The unmodified flybacks are good for "dinking around with high voltage" types of pursuits, but not much else.
- Richard Hull
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Re: FlybacK Transformers
Richard is correct and echo's my original statement. They are ready to go if you need under 3 ma on the output and under 25kv. 2 ma would demand external capacitors. These are fun supplies and not serious ones. Modern flybacks are just not modifiable. They gain their bullet proof HV capabilities through total encapsulation.
I have seen some incredible work done with the $80.00 all plastic, oil enclosed ACCEL professional high energy ignition coils. (there are several killer models available)
We had one guy at one of my old Teslathons pulling nasty and thunderous 4 inch arcs off one of these. Again, the drive for these would need to be electronic and you could not rely on even 5ma at 40kv. But they are a heck of a lot more robust than any flyback. Naturally, they would have to be externally rectified or multiplied and filtered. The modern flyback has all this in its guts but you can only count on a few hundred microamps.
I have heard of one guy who made a 150,000 supply out of one of these ACCEL coils. No data on the current, but I doubt if it would stand that voltage at more than 100ua. This is more of a multiplier filter related issue. The coil has no problem with 100 watt + output, I am told.
Virtually the entire issue of modern flybacks is one of toy or advanced toy grade HV supplies. Just enough to get you killed, maybe. Ancient flybacks are indeed much more versatile, but the low HV output demands an extra stage or two in the multiplier. 1950's flybacks were huge and very nice for modifying as they were over built. By the 60's they got a lot smaller in the core material and by the end of the B&W era they were downright microscopic. The earliest color sets might offer the best flybacks as they got big again, were still open core and rectification was done off board and the secondaries were a lot higher in voltage. They were starting to epoxy and silicone encapsulate the secondary pies too which was a real plus over the old hard wax impregnations of the 50's
For a fusor, long before I would even look at a flyback, I would be workin' a multiplier off a neon sign transformer. It has the energy one needs for light demo fusor work. Needless to say, no one will be doing real, 10e5n/s fusion off a TV flyback.
Richard Hull
I have seen some incredible work done with the $80.00 all plastic, oil enclosed ACCEL professional high energy ignition coils. (there are several killer models available)
We had one guy at one of my old Teslathons pulling nasty and thunderous 4 inch arcs off one of these. Again, the drive for these would need to be electronic and you could not rely on even 5ma at 40kv. But they are a heck of a lot more robust than any flyback. Naturally, they would have to be externally rectified or multiplied and filtered. The modern flyback has all this in its guts but you can only count on a few hundred microamps.
I have heard of one guy who made a 150,000 supply out of one of these ACCEL coils. No data on the current, but I doubt if it would stand that voltage at more than 100ua. This is more of a multiplier filter related issue. The coil has no problem with 100 watt + output, I am told.
Virtually the entire issue of modern flybacks is one of toy or advanced toy grade HV supplies. Just enough to get you killed, maybe. Ancient flybacks are indeed much more versatile, but the low HV output demands an extra stage or two in the multiplier. 1950's flybacks were huge and very nice for modifying as they were over built. By the 60's they got a lot smaller in the core material and by the end of the B&W era they were downright microscopic. The earliest color sets might offer the best flybacks as they got big again, were still open core and rectification was done off board and the secondaries were a lot higher in voltage. They were starting to epoxy and silicone encapsulate the secondary pies too which was a real plus over the old hard wax impregnations of the 50's
For a fusor, long before I would even look at a flyback, I would be workin' a multiplier off a neon sign transformer. It has the energy one needs for light demo fusor work. Needless to say, no one will be doing real, 10e5n/s fusion off a TV flyback.
Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
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Re: FlybacK Transformers
One serious problem with modern flybacks is that the diodes are build into the device, which generates positive high voltage.
Fusors require negitive high voltage.
I've tried reversing the polarity by grounding the positive lead and picking the negitive from the bottom pins, but interal arching occurs. Before we gave up on this, it did produce a faint possier in the fusor... but at the same time I could hear arcs between the flyback core and the flyback primary wound on the core.
Fusors require negitive high voltage.
I've tried reversing the polarity by grounding the positive lead and picking the negitive from the bottom pins, but interal arching occurs. Before we gave up on this, it did produce a faint possier in the fusor... but at the same time I could hear arcs between the flyback core and the flyback primary wound on the core.
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Re: FlybacK Transformers
Maybe not 10^5, but 10^3 to 10^4 might be possible with a well-built system. Scott Little reported around 10^4 neutrons/sec with a pretty modest 20kV power pack.
- Richard Hull
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Re: FlybacK Transformers
This is the probelm with many HV supplies that would otherwise be great for fusor use. About 99% of all super HV supplies are permanently wired for positive hot output. Most versatile supplies can have their polarity changed. As such, they are rarely found surplus. They are used to death.
Most of the time the reversal in a versatile supply is accomplished in a major mission to the interior bowels of the device where a plexiglass plate with bannana plugs is removed and rotated 90 degrees.
Richard Hull
Most of the time the reversal in a versatile supply is accomplished in a major mission to the interior bowels of the device where a plexiglass plate with bannana plugs is removed and rotated 90 degrees.
Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
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Re: FlybacK Transformers
You can remove the diode from the secondary by "dremeling" it out (cutting) and jumpering to it. There is not much wire to work with and you need to worry about corona loss, but it does work.
At least it works for those flybacks that have their secondary arms jutting out at an angle from the body.
-Dave
At least it works for those flybacks that have their secondary arms jutting out at an angle from the body.
-Dave
- Richard Hull
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Re: FlybacK Transformers
Man! That is an up hill battle. Avoid swimming upstream against epoxy potting. If it were a 20 pound potted ferrite transformer core with some watts behind it... maybe. But, not a tiny little 10 watt flyback. I guess if one gets desparate enough for volts of a certain flavor, most anything seems reasonable.
Sony uses no less than 5 little 8kv micro diodes in their flybacks with five windings in series, (diode, winding, diode, winding, etc.), to reduce diode size and voltage burden over the winding. The whole thing is potted.
Richard Hull
Sony uses no less than 5 little 8kv micro diodes in their flybacks with five windings in series, (diode, winding, diode, winding, etc.), to reduce diode size and voltage burden over the winding. The whole thing is potted.
Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment