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  1. kallen88

    Safety Circuit for Rotating Machinery

    Hello Everyone, Just a quick question regarding safety stopping function of a rotating machine control system. Say I have 2 solenoid locks on two different movable guards and 2 e-stop buttons. I want to design a CAT 3 system to bring the rotating machine to a controlled stop with removal of...
  2. kallen88

    Another DCS vs PLC thread.

    Hello People, Sorry for another DCS vs PLC topic but I have a few questions that aren't really addressed in most of the thread questions I have found. I have been looking to SCADA and DCS systems and there is a lot of information out there defining them but no real 'practical' information. It...
  3. kallen88

    Career help / covering letter help

    Greg, I do see your point but I do tend to agree with rotaryw about expressing strengths rather than how to get around caveats, up until the interview process anyway. I would rather answer this in person. I do agree that finding the core requirements are essential so I would not apply for a...
  4. kallen88

    Good reference material - Process control

    Hello There, Can anyone recommend some good text books or online material relating to the design and management of process control systems? In particular, mineral beneficiation processes. I want a good general text, or a couple, I can refer to help with the design process from control...
  5. kallen88

    Career help / covering letter help

    Ok, thank you all. Good advice in there. I can see the benefits to both approaches, either being 100% honest but careful in pointing out the lack of experience and ways to overcome, or not saying anything and really concentrate on my strengths. I suppose I will have to pick an approach and be...
  6. kallen88

    Alarm design for mineral process plant

    Hello, thanks for the responses. Compositepro - What exactly disturbs you about what I have written? I do get that a full understanding of the process is key to determine proper operational and design constraints for equipment and personnel. I have helped with the design of 3 previous pilot...
  7. kallen88

    Alarm design for mineral process plant

    Hello, I am currently helping develop a control system for a simple mineral process plant and need some assistance with alarming, in particular, when to deiced if an alarm is necessary or not. I am not 100% familiar with the process just yet but I have an idea of the critical aspects. I have a...
  8. kallen88

    Career help / covering letter help

    Thank you for the responses. I figured that was the best approach. However I do think the aforementioned position is for a more mid to senior level where I would still sit in the graduate level of experience. The company is one I would be very interested in working for so I am wondering if it...
  9. kallen88

    Career help / covering letter help

    Hello Forum, Hope this is appropriate to post here but I really need some advice. I am trying to figure out what I can do about my career situation and I have a question relating to job applications specifically cover letter and resume details. Ill start with a bit of context. I am a...
  10. kallen88

    Red Lion Crimson 3 emulator logging

    Hello All, I am developing an interface and data logging system for a Red Lion G306 HMI. I don't have the hardware yet so I am using the emulator which is working pretty well so far as I have it communicating with real hardware such as the PLC. For this job I am required to log sets of data...
  11. kallen88

    Circuit breaker practical trip time under short circuit

    The distance between the 50A breaker and control panel is about 6m of 16mm2 cable and yes it is all 3 phase. Thanks.
  12. kallen88

    Circuit breaker practical trip time under short circuit

    Ok Thanks for all your help. Hope I havnt taken too much of your time, this has been a rather long thread. I do not have the exact lengths of the cables between boards, I made an estimate based on the physical distances between them and the current carrying capacity of the cables from the...
  13. kallen88

    Circuit breaker practical trip time under short circuit

    Hello again, Ok so I am still trying to decide if I can be reasonably confident now that the 6kA breakers to be installed will be protected through cascading with the fault level available. The MCCB in the distribution board feeding the smaller breaker is a Schneider NXS100B. I found the...
  14. kallen88

    Circuit breaker practical trip time under short circuit

    Ok I think I am finally starting to understand how everything fits together. I read through a technical document from Hager explaining all the concepts you are talking about with some nice examples. It also cleared up some other concepts I knew about but did not fully understand such as where...
  15. kallen88

    Circuit breaker practical trip time under short circuit

    Cheers, My calculation came out at 19.48 kA. I also tried to calculate the total resistance between the LV terminals and the distribution board in question to ensure a maximum fault of 6kA and came out to 0.027 ohms. Does this seem correct? Also the drawings provisions are that a 25kA SPD be...
  16. kallen88

    Circuit breaker practical trip time under short circuit

    By dedicated plant I mean plant that is for a dedicated purpose that may or may not be incorporated into a larger system, controlled on a local level. Not necessarily with its own dedicated switchboard but has it's own switchgear to protect it's circuit branches for equipment such as motors...
  17. kallen88

    Circuit breaker practical trip time under short circuit

    Thanks again, From the training workshop I did perform some example calculations and were given resources to estimate the transformer % impedance from its power and primary/secondary voltages to find the prospected fault current so if I had the information I would be comfortable. We operate in...
  18. kallen88

    Circuit breaker practical trip time under short circuit

    Thank you all for your input. healyx, there is some information I can find on Hager devices although very general and have not seen any figures in their documentation relating to a specific devices let-though energy. I suppose the next step would be to contact our suppliers or Hager themselves...
  19. kallen88

    Circuit breaker practical trip time under short circuit

    I have access to the AS 60898.1 but I cannot find information anywhere on the A^2s classes. I have found a reference to the EN 60898 annex ZA with the class tables. The MCBs being used in our application are from Hager, which according to their catalogue are to 60898. From the tables it states...
  20. kallen88

    Circuit breaker practical trip time under short circuit

    Yes sorry, Miniature Circuit Breakers was what I was referring to. The control panel will be fed from a distribution board which is already in place. All the switchgear on this board is rated at 6kA and I do understand that this is not necessarily the SC capacity but its the only figure I have...
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