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Need help with HV Power Supply

  • 22-02-2008 12:20PM
    #1
    killerwatt
    Closed Accounts Posts: 13 ✭


    Hi

    I'm looking for a specific transformer that does the following:

    - Using domestic power supply (Ireland)
    - Uses a high voltage transformer 0V - 50Kilovolts
    - capable of 0mA - 100mA (milliamp)
    - With a Variac type control to vary the voltage, and the amps applied.

    Now, I've seen plans for a similar spec machine see below:
    http://www.instructables.com/id/Buil...-Power-Supply/

    But I'd rather buy/acquire one rather than do it myself or even pay someone to assemble the above for me...;)

    - If someone out there is an expert and can do it, I'd be interested in talking.
    - If someone can point me in the direction of a cheap version thats already on the market, I'd love to hear. I've already checked commercial suppliers and prices are in the megabuck range.
    - So if someone has a economical advice for me I'd appreciate it a lot.

    And before you ask, this is to power some high voltage plasma work.


Comments

  • #2
    DublinDilbert
    Registered Users, Registered Users 2 Posts: 5,425 ✭✭✭DublinDilbert


    killerwatt wrote: »
    Hi

    I'm looking for a specific transformer that does the following:

    - Using domestic power supply (Ireland)
    - Uses a high voltage transformer 0V - 50Kilovolts
    - capable of 0mA - 100mA (milliamp)
    - With a Variac type control to vary the voltage, and the amps applied.

    Now, I've seen plans for a similar spec machine see below:
    http://www.instructables.com/id/Buil...-Power-Supply/

    But I'd rather buy/acquire one rather than do it myself or even pay someone to assemble the above for me...;)

    - If someone out there is an expert and can do it, I'd be interested in talking.
    - If someone can point me in the direction of a cheap version thats already on the market, I'd love to hear. I've already checked commercial suppliers and prices are in the megabuck range.
    - So if someone has a economical advice for me I'd appreciate it a lot.

    And before you ask, this is to power some high voltage plasma work.


    So you need 50KV out @ 100mA, that's approximately 5KW of power.... that's a serious power supply.... I don't think your going to get anything like that off the shelf, and not for a reasonable price tag...

    You'll probably need an inverter drive to chop into the primary at high frequency and a reasonable current... There is one clever system for building such a power supply, i'm not sure if its still covered by patents... my advise if you were to build such a power supply is built it up using 400V stages, i know that means you'll need 50,000/400 = 500/4 = 125 stages in series...


  • #3
    chris85
    Registered Users, Registered Users 2 Posts: 4,502 ✭✭✭chris85


    That would be a huge traffo you need there OP, I presume you know the theory behind how a traffo works. Getting 50 kV out will mean a huge traffo, you are talking an ESB substation there.

    Also I am very wary about where you are using this. If you are trying to use this of any residential supply you will be heavily penalised by the ESB. Residential networks have a certain demand that can be placed on the network, if you exceed this demand then you will face the fines/penalties and these arent cheap. Its not a matter of plugging in and swithching on when you are looking for so much electricity.


  • #4
    killerwatt
    Closed Accounts Posts: 13 ✭killerwatt


    Worst case, 50kv @ 100mA... typically 20kv @ <20mA....
    Know anyone that might be able to assemble a dc transformer like that?


  • #5
    DublinDilbert
    Registered Users, Registered Users 2 Posts: 5,425 ✭✭✭DublinDilbert


    killerwatt wrote: »
    Worst case, 50kv @ 100mA... typically 20kv @ <20mA....
    Know anyone that might be able to assemble a dc transformer like that?

    That's a key point, you will not get a DC output from a transformer, you will get AC... now at low voltages (and frequencies) all you need is a few rectifying diodes and capacitors and you have DC, try go to radionics and buy a 50KV diode, or 50KV capacitor.

    Many standard implementations would build up the 50KV using 10 x 5KV stages in series, but even if you go to radionics and try buy a 5KV diode it will be very expensive.

    You probably will not find anyone in ireland who can do anything like this...

    What is the application? some sort of X-ray tube??

    There are ways of building such a power supply, i have worked on some of these myself, they are not cheap...

    Any other thing you may want to look at is the energy storage in the system, how quickly can the power supply be discharge if there is a problem, from memory this is important for X-ray applications.


  • #6
    DublinDilbert
    Registered Users, Registered Users 2 Posts: 5,425 ✭✭✭DublinDilbert


    chris85 wrote: »
    That would be a huge traffo you need there OP, I presume you know the theory behind how a traffo works. Getting 50 kV out will mean a huge traffo, you are talking an ESB substation there.

    Ummmm not really.... for example a CRT TV has a 25K power supply from the fly back transformer.... your HT leads in your car will run at similar voltages...

    its all a question of how much power is required... hence my rough calculation so show its roughly 5KW of power...


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  • #7
    mawk
    Registered Users, Registered Users 2 Posts: 2,738 ✭✭✭mawk


    im pretty sure that domestic single phase power tops out at around 3.3kw and 50Kv @ 100Ma is going to be 5Kw.

    50Kv at 50MA might be do-able but if you much over that then id imagine you will start tripping.

    if you can work at a lower potential, life will be a lot easier


  • #8
    DublinDilbert
    Registered Users, Registered Users 2 Posts: 5,425 ✭✭✭DublinDilbert


    mawk wrote: »
    im pretty sure that domestic single phase power tops out at around 3.3kw and 50Kv @ 100Ma is going to be 5Kw.

    50Kv at 50MA might be do-able but if you much over that then id imagine you will start tripping.

    if you can work at a lower potential, life will be a lot easier

    P=VI => P/V = I => 3300/220 = 15A ??? so all that is available off a domestic supply is 15A?? why do they fit a 63A fuse in the supply?

    The typical domestic supply does not top out around 3.3KW. an electric shower is aprox 8.5KW alone...


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