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RadiPac: Quality assur­ance in produc­tion

Accu­racy classes are a measure of manu­fac­turing accu­racy

At ebm-papst, the focus of atten­tion is on making top quality fans. Docu­mented perfor­mance data and the correct choice of fan are only part of the story. It is also crucial to ensure that the fan is constructed in such a way that it actu­ally attains the spec­i­fied perfor­mance level in oper­a­tion, regard­less of the produc­tion date.

Fig. 1: Accu­racy class as per DIN 24166 (ISO 13348)*

A certain amount of toler­ance is inevitable with any tech­nical product, for example on account of dimen­sional devi­a­tions in compo­nents and assem­blies (e.g. enam­elled wire diam­e­ters or elec­tronic compo­nents). Toler­ance limits can be set and action can be taken to ensure that these are not exceeded. This is the job of a company’s Quality Assur­ance depart­ment.

And the greater the possible devi­a­tions and the resul­tant perfor­mance deficits, the greater the safety allowance required when selecting fans. DIN 24166 – “Fans; Tech­nical delivery condi­tions” there­fore defines accu­racy classes and permits devi­a­tions from the docu­mented perfor­mance char­ac­ter­is­tics. The so-called limiting devi­a­tions are divided into Classes 0 to 3. The stan­dard allows accu­racy class 3 for fans smaller than 10 kW for example (Fig. 1).

Top class RadiPac

EN_accuracy classes analysis_500h

Fig. 2: The accu­racy classes define produc­tion-related devi­a­tions from fan perfor­mance data. Accord­ingly the RadiPac product range attains Class 1. Analysis is based on perfor­mance measure­ments on 6,953 fans.

At the end of the produc­tion process, all RadiPac fans are checked in the as-deliv­ered condi­tion for any perfor­mance devi­a­tions. This quality assur­ance proce­dure involves recording all the elec­trical perfor­mance data and confirming compli­ance with the permis­sible manu­fac­turing toler­ances. Based on a size 500 RadiPac fan, analysis shows that ebm-papst attains accu­racy class 1 (Fig. 2). For air handling unit manu­fac­turers, this means that the figures given for the fan in the cata­logue and Product Selector must not differ from the actual drive perfor­mance by more than 2 % and from the total effi­ciency by more than 1 %.

Plan­ning reli­a­bility

Compar­ison of the product docu­men­ta­tion and the actual product deliv­ered reveals that in prac­tice the power consump­tion of the fan will be lower and the total effi­ciency level higher than the docu­mented figures. Conse­quently there is no risk of any unpleasant surprises when the air handling system goes into oper­a­tion and there is also no need for any precau­tionary over-dimen­sioning of the fan.

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