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  1. #31

    Padrão

    A função do cabo por fora é dar resistência menor até o solo, porque como os módulos são pintados e DEPOIS montados no lugar, PODE ter a situação do contato entre um módulo e outro ser meia-boca, tipo só 3mm de contato na tinta que descascou do lado de 1 dos 6 parafusos.

    Se a pintura for mesmo muito boa o contato entre um módulo e outro será ruim.

    Se quer ligar os dissipadores direto na torre usa o mesmo sistema dos dos isoladores mas sem o isolador, LIXA a tinta pra dar contato, coloca o conector parafusado, e bate um spray de tinta de cor similar mas minimizar oxidação no local.

    A construção exata depende do que comprar, esse tipo aqui é só botar o U de abraçadeira, mas tem que tirar a tinta pra dar contato com a estrutura da torre:
    Clique na imagem para uma versão maior

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    Esse já vem com abraçadeira, mas teria que curvar ele a força:
    Clique na imagem para uma versão maior

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    Se for comprar escova de aço em loja de ferragens, mais fácil soldar elas numa abraçadeira em U, são de ferro ou aço então pegam solda elétrica simples, bate uma tinta na solda, lixa a parte que vai fazer contato com a torre, depois bate o spray quando já estiver fixa, e pronto, contato garantido com a estrutura. O que não dá pra garantir sempre é que a estrutura está em contato decente com o solo (Mas pra dissipar estática deve estar, pra raio a tinta é problema mas pra dissipar estática pode ter condutividade um pouco pior).

  2. #32

    Padrão

    [QUOTE = raumaster; 842186] Hi Erdem!

    Thanks for spending your time answering all my doubts!

    Well, I don't know if in my country there is an obligation for metal towers to have lightning rods, which I know is every tower company uses it and also in many buildings there is one. In Brazil we have a regulation called NBR 5419: 2015, it was revised in 2015 and is a very big regulation book regarding all mainstream protection systems and good practices. I know there is an obligation for hospitals, churches and schools to have a lightning rod, but for telecom metal towers I have to check.

    I agree with all your others stataments, but talking about the price we have a big problem regarding our currency in Brazil, the "Real" is very devaluated in relation to the Dollar currency, more than 4 times lower which means for example, 3000 dollars get as high as $ 10,000 in our currency which is 11 times more then the minimium wage in our country so, it is a lot of money for us! With $ 10,000 I can pay for all radios installed in one tower ... At the moment we can't afford $ 10,000 plus taxes.



    ------------

    Dear Sir,

    That's exactly what I mean, everybody uses what everybody else uses. However, what they use do not solve the problem. If the problem was solved, you would not be in search of an alternative solution. Besides, once again, lightning rods can be used on buildings, there is nothing worng with it. They just can't be used on towers because they are not made to protect metal towers.

    I understand your concern about the pricing. As I told you earlier, please get in touch with your contact in MTO and there may be found a solution to this. Or, let me have your email address in a private message so that I can have one of my collegues get in touch with you.

    I also noticed some interesting (!) Ideas in the forum on using some brushes which can be found at local hardware stores to protect the tower from lightning. Guys, this is a serious business and serious solution which requires extreme attention and many calculations. There is a saying; "I am not rich enough to buy cheap stuff".

    Best Regards,

    Erdem



  3. #33

    Padrão

    [QUOTE = rubem; 842227] You would have to make or have an insulator look something like this:

    Anexo 69804

    For you to screw in any position of the tower, over the painting.

    I've seen the sale for $ 10, but also $ 50, as it is not always easy to find sometimes it is easier to order about 10 for any locksmith, take the pulley type insulators that you find in any building supply store ( http://judycabos.com.br/wp-content/u...-porcelana.jpg ) and have him make a bracket to screw in the tower without having to drill it (Tubular or angle, it is firm like ).

    Ideally, the cable should go outside the tower, from the top of the lightning conductor to the ground and follow the side of the tower, with these insulators separating more than 15cm from the structure. Attach the heat sinks to the cable, or take another cable (Thinner) to the heat sink attached to another insulator, perhaps on the other side of the tower and ready, you can keep the side of climbing the tower unhindered, with no heat sink or grounding cable in the way. / QUOTE]
    -----

    If you do not keep the down conductor cable at least 1,5 meters away from the tower, lightning current easily jumps to the tower legs and you will face with the same problem. These parts are made for ordinary buildings, not for towers.

    Regards,
    Erdem

  4. #34
    Avatar de Nilton Nakao
    Ingresso
    Sep 2013
    Localização
    Carlos Chagas, Minas Gerais
    Posts
    1.165

    Padrão Re: Sistema de prevenção contra raios.

    Ideal seria torres galvanizadas mas o alto custo as impedem inclusive até por parte das TELES, mas elas utilizam parafusos, porcas e arruelas estriadas e de pressão de altíssima torção; estas com o vento costumam afrouxar necessitando de manutenção preventiva.

    Em uma fazenda em torre triangula de 22 metros utilizei fio de arame liso( cerca de choque para gado) fixando rente à torre em cada face e nunca tive relato de danos devido ao raio. Dano que teve foi por conta do erro de eletricista que ligou acidentalmente o Neutro a fase de retorno da bomba elétrica de 7,5 CV.

    Quando se usa uma rede elétrica acima de 100 metros, costumo aterrar o Neutro distante 30 metros da antena e para-raio. Neutro e aterramento com apenas uma haste, mais devido a carga estática gerado pelo vento e indução da rede elétrica( já levei cada choque). Atualmente os quadros medidores padronizados pela Cemig, o Neutro e Terra são igualmente conectados mas na unidade consumidora precisa ser independente. Por norma as cores na rede de distribuição deveriam ser diferente, mas preguiça dos eletricistas ainda persiste em manter duas ou até 4 cores iguais.
    Parece mentira, mas nos locais onde corrigi a ligação na tomada parou de queimar equipamentos do nada principalmente. Me leva a conclusão que pode ter para-raio excelente, aterramento excelente mas rede elétrica não está de acordo com o mínimo das conformidades previstas pelos órgãos competentes. Ideal seria se aplicarmos as normas utilizadas em petrolíferas ou aeronaves.



  5. #35

    Padrão Re: Sistema de prevenção contra raios.

    Na duvida busque Soluçoes ja pronta mesma como a do ebay que acaba saindo uns 200 reais cada ai da pra umas 5 gastar uns 1000 para por nas torres .
    Quando a torre o ideal e lixar um pedaço de cada modulo bem na proximidade deles e interligar cada modo com fio e pintar a parte lixada ate chegar no ultimo modulo e esse aterrar com hastes com 2 a 4 hastes de cobre como o Rubem mencionou. Desse jeito não vai sair tao caro quando o outro conceito e vai ser uma solução profissional. Essa empresa vende daquele anuncio da ebay https://lightningmaster.com/product-...ng-protection/.
    Site que faz um meio que gambiarra http://w4zt.com/porcupine/

  6. #36

    Padrão

    Citação Postado originalmente por ErdemOzkan Ver Post

    ------------

    Dear Sir,

    That's exactly what I mean, everybody uses what everybody else uses. However, what they use do not solve the problem. If the problem was solved, you would not be in search of an alternative solution. Besides, once again, lightning rods can be used on buildings, there is nothing worng with it. They just can't be used on towers because they are not made to protect metal towers.

    I understand your concern about the pricing. As I told you earlier, please get in touch with your contact in MTO and there may be found a solution to this. Or, let me have your email address in a private message so that I can have one of my collegues get in touch with you.

    I also noticed some interesting (!) Ideas in the forum on using some brushes which can be found at local hardware stores to protect the tower from lightning. Guys, this is a serious business and serious solution which requires extreme attention and many calculations. There is a saying; "I am not rich enough to buy cheap stuff".

    Best Regards,

    Erdem

    Hi, Erdem! How are you?

    I was reading through all the e-mails I exchanged with Silvia Toprak last year, in August to be exact and we talked about pricing and such and apart from the price of the product itself, there is the freight price of DHL, at that time it was 470 dollars. Our government is so "evil" to its people that it includes the taxes in the total price of the product including the freight itself! If I have to pay lets say, 2000,00 USD for a product and pay 470 USD for the freight, they include taxes of 60% over the total price, which will make us pay 1482,00 in taxes only, almost doubles the price! To make things worse, the USD is over R$ 4,10 as of October 2019. To put it in simple words, in the end for us brazilians, it would be the same as paying 16000,00 USD for someone that earns its sallary in dollars. Really expensive! Your products ARE NOT expensive for what it do. My country is expensive! My government is shit!




    Citação Postado originalmente por ErdemOzkan;842258QUOTE
    -----

    If you do not keep the down conductor cable at least 1,5 meters away from the tower, lightning current easily jumps to the tower legs and you will face with the same problem. These parts are made for ordinary buildings, not for towers.

    Regards,
    Erdem

    I don't understand one thing. In one of the documents Silvia sent me last year, there is a project model where you guys from MTO states that the grounding system resistence must be 5 ohms or less. But Silvia told me that I should remove the lightning rod currently installed AND the copper down conductor. People here in this discussion are saying that these kinds of dissipators needs to be grounded to work correctly or that the tower itself should be grounded. My towers are painted, how can a painted tower make a good electrical contact with your EVODIS product so as to dissipate charges? Isnt it logical that the tower has to have some kind of grounding systems for your product to work and not be painted because as far as I know, many kinds of paints isolate the electrical contact with the metal, makes the electricity not flow very well... What do you have to say about that? Here is the part of the document Silvia sent me last year:

    Clique na imagem para uma versão maior

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