Hey Everyone,
I am currently in the process of selecting parts for my HV circuitry for my demo fusor and, with the help of the FRQ's, came to understand a lot more about electronics. However, one component I can't find much information on is the ballasting resistor. From what I could find on the internet, this component seems to limit the current of a line, but why is that important in fusor applications? Why exactly is it needed? Lastly, is this an acceptable ballast resistor for my demo fusor?
https://www.zaversone.com/index.php?mai ... _id=242263
Thank you!
River M.
Ballasting Resistors?
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Ballasting Resistors?
I'm new to this but eager to learn so if I sound dumb please correct me!
- Richard Hull
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Re: Ballasting Resistors?
Did you read my FAQ on Ballasting resistors?
viewtopic.php?f=29&t=13497&p=87915#p87915
These are usually 5-inches to 12-inches long in the value and wattage we would typically need. They are rather rare now as they were much more common to the vacuum tube era.
The thing is that they are rather large and ugly and are green or brown in color. I attach an image of the type thing you will need if your supply demands a ballast resistor. pay no attention to the value in the image as it is too low, but the wattage dictates the size.
Richard Hull
viewtopic.php?f=29&t=13497&p=87915#p87915
These are usually 5-inches to 12-inches long in the value and wattage we would typically need. They are rather rare now as they were much more common to the vacuum tube era.
The thing is that they are rather large and ugly and are green or brown in color. I attach an image of the type thing you will need if your supply demands a ballast resistor. pay no attention to the value in the image as it is too low, but the wattage dictates the size.
Richard Hull
- Attachments
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- This is the typical size of a ballast resistor.
- power resistor.jpg (45.94 KiB) Viewed 1475 times
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: Ballasting Resistors?
River
the ballast resistor helps the power supply to not collapse totally in output quickly ie it limits dV/dt
I use those same resistors that you have found but I use 5x 10k ohm ones in series a single resistor will flash over to the aluminium case at a few kv. and as you can guess 30-100k ohms is about the right size for a fusor
the ballast resistor helps the power supply to not collapse totally in output quickly ie it limits dV/dt
I use those same resistors that you have found but I use 5x 10k ohm ones in series a single resistor will flash over to the aluminium case at a few kv. and as you can guess 30-100k ohms is about the right size for a fusor
- Richard Hull
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Re: Ballasting Resistors?
The aluminum case is the killer. Never use those resistors. During a ballast action, all of the load voltage might appear across the resistor. The resistor I show is pure ceramic and cannot arc over. the only metal allowed is the internal, fine, high resistance wire and the large two end lugs. No metal body allowed.
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
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- Posts: 12
- Joined: Thu Dec 17, 2020 9:58 am
- Real name: River Marlowe
Re: Ballasting Resistors?
I read the ballasting FRQ but was under the false impression that ballasting the NST and a ballasting resistor were two separate components. I am using a 60hz Franceformer so ballasting won't be an issue for me.
Thank you all!
River M.
Thank you all!
River M.
I'm new to this but eager to learn so if I sound dumb please correct me!
- Richard Hull
- Moderator
- Posts: 15032
- Joined: Fri Jun 15, 2001 9:44 am
- Real name: Richard Hull
Re: Ballasting Resistors?
Yes, that is what FAQs are all about......Explaining, in some detail, specific issues.
All classic, heavy, old school, neon sign transformers are magnetically shunted and cannot be overloaded with even a dead short!! They are a beautiful example of 1920's magnetic design.
The feather weight new class of switched electronic designs are rather useless for demo fusor purposes. "If it weighs a ton, you have won." "If it is feather light, you have lost the fight"
Richard Hull
All classic, heavy, old school, neon sign transformers are magnetically shunted and cannot be overloaded with even a dead short!! They are a beautiful example of 1920's magnetic design.
The feather weight new class of switched electronic designs are rather useless for demo fusor purposes. "If it weighs a ton, you have won." "If it is feather light, you have lost the fight"
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