Rules and Guidelines
Want to participate in the discussions? Please read our Community Rules and Guidelines. Need some help? Visit Support and Answers.

  • State Not Answered
  • Locked Locked
  • Replies 5 replies
  • Subscribers 9 subscribers
  • Views 149 views
  • Users 0 members are here
Options
You may also be interested in
This discussion is locked.
You cannot post a reply to this discussion. If you have a question start a new discussion

Carbon Composition Resistors

Roger B


A significant number of our accelerators use old style Allen Bradley 2W carbon resistors like these:

c49bf42fa082a060e0cceb7b2961599d-huge-160906-def-widerstand1.jpg


The accelerator supplier, IBA, can no longer supply them. They have an alternative but do not recommend mixing old and new due to different aging characteristics.


Does anyone know of a supplier of these resistors, generally in the meg ohm range? I would only be looking for small numbers to repair damaged strings like above.


Anecdotally there was a previous problem with this type of resistor where the manufacturing process was changed so that the internal end of the leads was cut to a chisel point which resulted in them exploding when a high voltage was applied.


Best regards


Roger

  • Former Community Member
    0 Former Community Member
    I've asked around and unfortunately all our stocks of those Allen Bradley resistors were disposed of at least 7 years ago because we finally wound down our operational support capabilities for the 665 kV HV platform (we now have a 665 keV RFQ).


    What a shame. If only this network had existed then we could have given away all that sort of thing to a good home. We know from experience that it is practically impossible to find similar characteristics/quality replacements these days. You might have to look at complete replacement of all your resistors in those chains.


    We by stuff from Willow and PPM. Other suppliers are also out there! It would be great to hear their opinions.

    http://www.willow.co.uk/

    http://ppmpower.co.uk/



    Cheers,

    Dan

  • Former Community Member
    0 Former Community Member
    Dear Roger,

    Please drop us a specification for the chain and we'll see what we can provide. Are they 30M 5%? What is the voltage (peak) and duty, do you really need 12W per string? Do they really need to be carbon?

    We don't have anything that "looks" or is spec'd like those individual devices, but if you are open to other options I think we could help.

    Many thanks

    Phil


    psurman@ppm.co.uk
  • 0
    Thank you both for your replies.

    The manufacturer can supply an alternative but they recommend replacement of the complete set of 96 chains which is a little expensive. The chains are made up of 12 x 10Mohm resistors. Each chain drops up to 35kV DC and operates in 6 Bar of SF6. The chains are installed around an accellerator tube so the length is important.


    Best regards


    Roger
  • Former Community Member
    0 Former Community Member
    Why do you cant used new Resisters for replacing all that old resisters 

  • 0
    The problem is that resistors are not perfect. They may have the same value when measured with a low DC current but the response with high voltages and frequencies is different. If I mix resistor types the voltage grading will not be constant which can result in beam instabilities and sparking.

    I can replace the complete set but that will cost quite a few 1000s.


    Best regards


    Roger

Join us to get the best from IET EngX.

Joining EngX lets you personalise your experience so you stay up to date on the topics that interest you, plus you’ll be able to make connections who are looking to collaborate, exchange ideas and more.

Join us Not now

Community Rules & Guidelines