Dou­ble ends 

The JÄGER Group secures gen­er­a­tors in case of light­ning strike 






High­est require­ments for light­ning strikes

The experts at Jäger are meet­ing these chal­lenges, but the fun­da­men­tals for this must first be clar­i­fied. The hub of a wind tur­bine is bolt­ed to the rotor of the gen­er­a­tor from 72 to 108 dou­ble ends, depend­ing on its size. Each of these met­al bolts should be ful­ly pro­tect­ed in the shaft area. This means that the hose must not only fit tight­ly, but also be pre­cise in its length and diam­e­ter. The spe­cial com­pound select­ed must also meet the require­ments per­ma­nent­ly: It must be extreme­ly flex­i­ble and must not be dam­aged at all dur­ing the assem­bly process. A tiny hole would destroy the surge pro­tec­tion. In addi­tion, it must be ensured that no mois­ture can pen­e­trate between the shaft of the dou­ble end and the hose.

Jäger tests such prop­er­ties in a spe­cial plunge pool. The dou­ble ends, in this case with a diam­e­ter of 42 mil­lime­ters and a length of 506 mil­lime­ters, are already cov­ered with the spe­cial hose. The pres­sure gen­er­at­ed sim­u­lates the pres­sure pre­vail­ing on the sys­tem under full load. The dou­ble ends and the spe­cial hose are designed for the life cycle of a wind tur­bine, which is cal­cu­lat­ed at 25 years.

But the engi­neers have not yet reached that point. All pre­vi­ous attempts to apply a hose to the dou­ble ends have failed. All too often the hose, whose inner diam­e­ter is small­er than the out­er diam­e­ter of the dou­ble end, is over­stretched and no longer ful­fills its intend­ed func­tion. The qual­i­ty of the man­u­fac­tured com­po­nents is not in ques­tion. The assem­bly process is the key.


Intel­li­gent adjust­ment with great effect

The hose and com­pound experts at Jäger Gum­mi und Kun­st­stoff devel­op a hose that is tai­lored to the spe­cif­ic appli­ca­tion in its com­pound com­po­si­tion and result­ing prop­er­ties. The spe­cial hose is man­u­fac­tured with a slight­ly high­er wall thick­ness than before. In a com­pressed air process, the hose can now be applied to the dou­ble end with­out dam­age. The air pres­sure stretch­es the hose just enough to allow it to be brought over the thread area and shaft of the dou­ble end. After­wards, how­ev­er, the hose con­tracts to such an extent that it sits firm­ly and water­tight on the dou­ble end.

The dou­ble ends have a hot-dip gal­va­nized sur­face to pro­tect them against cor­ro­sion. How­ev­er, tiny chips and zinc residues can remain in the thread area. Such sharp chip edges are fatal for the pro­tec­tive hose. For this rea­son, Jäger’s experts check every sin­gle dou­ble end very care­ful­ly: Their tol­er­ance range here is in the tenth of a mil­lime­ter. But this is only the first step, because the col­lar length of the hose must still be short­ened precisely!

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Accu­rate to a tenth of a millimeter

Cut­ting devices spe­cial­ly devel­oped by Jäger short­en the hose to a tenth of a mil­lime­ter. Min­i­mized waste ensures min­i­mum pro­duc­tion costs. The blade stops pre­cise­ly to pro­tect the impor­tant zinc coat­ing of the dou­ble end. The surge pro­tec­tion is made per­fect by an addi­tion­al­ly applied sil­i­cone seal of the hose end on the bolt itself. This pre­ci­sion and care can be proven at any time: Each indi­vid­ual dou­ble end is num­bered and can be traced back to its batch num­ber. The same applies to the hose applied to it.

For Jäger Gum­mi und Kun­st­stoff, the devel­op­ment and pro­duc­tion of this surge pro­tec­tion for dou­ble ends is a mile­stone as a long-stand­ing sup­pli­er to the wind ener­gy indus­try. All goals have been achieved, the require­ments for the fin­ished prod­uct have been ful­filled. Process-safe pro­duc­tion and deliv­ery on time of the pre­pared dou­ble ends are guaranteed.

Your con­tact for surge protection:

Loca­tion Man­age­ment Oldenburg

T. Dyck­rup

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