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 31 replies
  • Subscribers 32 subscribers
  • Views 3033 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

LED inrush current and generator set

Julien Leblanc
Hello,


I'm currently working on a sport field application where i need to power some LED reflectors (30 kW total).

I will also use a generator set, in case the network fails.


The inrush current of the reflectors is 3 times higher than their rated current, but the duration is only 0.2ms.


Could anybody tell me if i should take into account the inrush current when I choose the generator set power (that is, to oversize the generator)?

Or i should ignore the inrush current and set the power of the generator a bit higher than the total power of the reflectors?

I'm not talking about the circuit breakers of generator's outputs. Let's say one can choose them so that they don't trip.

If those breakers don't trip, is it possible that anything else happen to the generator set, because of the inrush current?


I've been searching through the specifications of many generator sets, but i cannot find any data on this specific problem (short overload).






Parents
  • 0
    Harry Macdonald:

    There are installations where a diesel generator assumes full load in 3 seconds from cold start but they are rather specialist and I don't know to what extent the generator was oversized to allow this.

    I don't think it unreasonable to start the generator immediately but to let it run for 5 secs before initialing the change over to see if it is a real power cut. Then you hit the step load issue and need to keep the load steps below 1/4 of capacity per step so 5 steps changes in the next 5 seconds should be reasonable.

    However this all needs careful control and you also need to think about how the transfer back to mains power is arranged. Automatic or manual? What happens if the power if restored while the loads are being switched on the the generator?


    Sorry for the delayed answer.

    Thank you for reminding me about these details.

    I think that the simplest way is that the transfer back to mains to be made manually. I think some ATS have implemented this function - i found this text on a specification: "if the mains supply becomes available again before the generator circuit breaker has closed then the mains circuit breaker remains closed (or recloses if it has opened) and the generator will not go on load.".

    Are all these details manageable by a PLC?


Reply
  • 0
    Harry Macdonald:

    There are installations where a diesel generator assumes full load in 3 seconds from cold start but they are rather specialist and I don't know to what extent the generator was oversized to allow this.

    I don't think it unreasonable to start the generator immediately but to let it run for 5 secs before initialing the change over to see if it is a real power cut. Then you hit the step load issue and need to keep the load steps below 1/4 of capacity per step so 5 steps changes in the next 5 seconds should be reasonable.

    However this all needs careful control and you also need to think about how the transfer back to mains power is arranged. Automatic or manual? What happens if the power if restored while the loads are being switched on the the generator?


    Sorry for the delayed answer.

    Thank you for reminding me about these details.

    I think that the simplest way is that the transfer back to mains to be made manually. I think some ATS have implemented this function - i found this text on a specification: "if the mains supply becomes available again before the generator circuit breaker has closed then the mains circuit breaker remains closed (or recloses if it has opened) and the generator will not go on load.".

    Are all these details manageable by a PLC?


Children
No Data

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