I can never figure out what's supposed to be funny when I'm always in a dictionary with you two.Wordplay, thy name is Aleph!
I can never figure out what's supposed to be funny when I'm always in a dictionary with you two.Wordplay, thy name is Aleph!
Collar me, don't collar me I've got my rays, I've got my family treeI can never figure out what's supposed to be funny when I'm always in a dictionary with you two.
I have looked at small-sized ferrite transformers available commercially. The best I could find in power(watts) to weight(grams) ratio were in the range of 1 to 3, i.e., to get 10 watts you needed 30 grams weight for the transformer. See for example the ones here:It turns out the higher frequencies attending practical operation of 'air core' power transformer topologies entail greater radiation and proximity/skin effect losses -- While the latter may be mitigated via 'special' winding technique (e.g. windings fashioned of 'litz wire', etc.) and the former via 'tuned' shielding -- said measures tend to compare unfavorably with ferrite (or Fe powder) core units as regards mass 'conservation' --- Then too are the more stringent resonant capacitor requirements (and, hence, overall driver weight)...
For all that, was there a practical method for power rectification (as opposed to 'detection') at frequencies > 10MHz -- very lightweight DC EHT PSUs would be a 'snap'
FWIW I strongly urge you to investigate ferrite transformers --- For instance, many LOPTs salvaged from large (CRT) TVs may be operated to 500W well-neigh continuously (in open air)
Best regards and again good luck!
HP
What will be the power source for your lifter? Won't a battery be a significant contributor to overall HV supply weight?I have looked at small-sized ferrite transformers available commercially. The best I could find in power(watts) to weight(grams) ratio were in the range of 1 to 3, i.e., to get 10 watts you needed 30 grams weight for the transformer. See for example the ones here:
http://www.ultravolt.com/uv_docs/HPCDS.pdf
But you need this ratio to go in the other direction or at least be above 1 to 1. The reason is due to the lifters limited thrust to power ratio, i.e., how much they can lift for the power input. It's in the range of 1 gram-force per watt. So for instance if you had a lifter running on 10 watts it could lift only 10 grams. But the transformer giving you the high voltage needed would weigh at best 30 grams, so the lifter couldn't raise it.
Bob Clark
Have you ever seen one of these that are self powered? Of the many videos I've seen they are all tethered to the power supply on the ground by a wire. Don't think that they have the lifting capabilities to be self powered.But you need this ratio to go in the other direction or at least be above 1 to 1. The reason is due to the lifters limited thrust to power ratio, i.e., how much they can lift for the power input.
@Robert Clark Yesterday you posted (the relevant part of) the above to your other thread where I showed you an example of a commonly available device capable of > 2W Per Gm HEREI have looked at small-sized ferrite transformers available commercially. The best I could find in power(watts) to weight(grams) ratio were in the range of 1 to 3, i.e., to get 10 watts you needed 30 grams weight for the transformer. See for example the ones here:
http://www.ultravolt.com/uv_docs/HPCDS.pdf
But you need this ratio to go in the other direction or at least be above 1 to 1. The reason is due to the lifters limited thrust to power ratio, i.e., how much they can lift for the power input. It's in the range of 1 gram-force per watt. So for instance if you had a lifter running on 10 watts it could lift only 10 grams. But the transformer giving you the high voltage needed would weigh at best 30 grams, so the lifter couldn't raise it.
Bob Clark
Indeed, as previously stated, I feel such will be his principal difficulty...What will be the power source for your lifter? Won't a battery be a significant contributor to overall HV supply weight?
FWIW The device imaged in post #65 is a Pie-Wound air core transformer typically employed in ye olde "RF HVPSUs" -- Unfortunately they tend to fail at power levels much greater than 30W and/or operating EMFs > Ca. 25 kV --- Tho I'll grant that they're not without their 'old world charm' you'll find them less than useful in applications more demanding than low-power demonstration (Typically 25KVP @ 1mA intermittent) Beware, also, The Scourge of The Pie-Wound' Inductor! -- CIP Said device is prey of copious self-resonances over it's (ostensible) operating range...Here's an example of an "air" core transformer good for some fairly high voltage.
That's why he requires a 'decent' Power:Mass ratio --- While I believe a small (i.e. ≤ 5 kg), self-contained ion propelled 'drone' might be implemented via electronic PSUs -- larger (manned [personed?]) designs may (quite counterintuitively) prove more 'amenable' to VDG generator techniques -- That said, Tesla Coils may be worth another look as applied to large-scale designsHave you ever seen one of these that are self powered? Of the many videos I've seen they are all tethered to the power supply on the ground by a wire. Don't think that they have the lifting capabilities to be self powered.
You are correct; that is the key reason why they have not been a practical means of propulsion. The power supplies needed to provide the voltage at tens of thousands of volts are too heavy for the lifters to raise. Do a google image search on "lifters", "power supply", "high voltage". You'll see the lifters are very light weight devices at a few grams, but the power supplies are large and heavy in the range of kilograms.Have you ever seen one of these that are self powered? Of the many videos I've seen they are all tethered to the power supply on the ground by a wire. Don't think that they have the lifting capabilities to be self powered.
That surprised me! -- Albeit pleasantly so!But actually the batteries needed to supply the power at light weight already exist.
Thanks for that. Interestingly the high power batteries needed already exist. These are used for RC aircraft and drones to provide the high power to drive the propellers and rotors, but at the light weight needed for the aircraft. They are also used for batteries to provide the cranking power to start a car when your car battery is dead, but can yet fit in your shirt pocket.What will be the power source for your lifter? Won't a battery be a significant contributor to overall HV supply weight?
Here's an example of an "air" core transformer good for some fairly high voltage. It could be described as a compact tesla coil. The secondary is resonant around 100 kHz so litz is not needed, nor is radiation loss a problem at that frequency. I found it as a surplus item but I've been told that it's used in Glassman high voltage supplies. I'm not sure what it weighs; feels like 100 to 200 grams.
View attachment 110546
Are you talking about lithium batteries?But actually the batteries needed to supply the power at light weight already exist.
---EMPHASIS ADDED---Thanks for that. The primary winding is necessary for the transformer operation. So by changing it out, are you referring to decreasing the number of windings on the primary to increase the multiplication factor of the voltage?
Bob Clark
Yes. I wondered about using such electrostatic voltage generators such as the Van der Graaf which can provide hundreds of thousands of volts for the lifters. They usually do these at low current though. I would have to see what is the power output to see if it would work for the lifters.That's why he requires a 'decent' Power:Mass ratio --- While I believe a small (i.e. ≤ 5 kg), self-contained ion propelled 'drone' might be implemented via electronic PSUs -- larger (manned [personed?]) designs may (quite counterintuitively) prove more 'amenable' to VDG generator techniques -- That said, Tesla Coils may be worth another look as applied to large-scale designs
Very best regards
HP
--EMPHASIS ADDED--Yes. I wondered about using such electrostatic voltage generators such as the Van der Graaf which can provided hundreds of thousands of volts for the lifters. They usually do these at low current though. I would have to see what is the power output to see if it would work for the lifters.
Bob Clark
Yes. Do a google search on lithium car starter batteries for other examples.Are you talking about lithium batteries?
Aye! Andy M. (aka 'Photonicinduction' of YouTube fame) had loads of fun with those! -- Which is to say they're all they're claimed to be and then some!Yes. Do a google search on lithium car starter batteries for other examples.
Bob Clark
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