Dynamo belt tension

[MG]

yeah, but then there is the problem of translating the required pre-tension force (or oscillation frequency for that matter) into the appropriate twisting torque, i.e. some sort of calibration will be required.
I have found a post on another forum, where one of the guys wrote a LabView program to measure the oscillation frequency of car engine timing belts, using a laptop and microphone, just like those small hand-held devices do it. Unfortunately the link is broken. 
Anyone here good at Fourier analysis and software programming?   

[manosound]

Markus,  et al,

Not that I am anyone to challenge the belt manufacturer's or your (Markus's)  mechanical engineering calcs,  but I have a question. In the power calculating program,  the number of teeth in mesh on the driven pulley is given as seven. The drawing would appear to support this,  however,  it seems to me that only half that many could be working a any given time,  as the top run of the belt is in tension while the bottom is trying uselessly to push. Then,  I wonder if more than even the first couple of meshed teeth are truly working, the work having been mostly done before getting to,  say,  the third meshed tooth. If correct,  would this change the results for maximum power that the belt could tranfer?

On the question of oil or grease in the case, i can't see how it would hurt, as the belt can't possibly be depending on static friction from the face of the teeth to avoid slipping around the pulley.  At the same time I don't see how it would help.

Richaed L.

[MG]

Hello Richard!
You are right about the bottom of the belt being more or less uselessly "pushing" the pulley, hence the need for pre-tension in the belt to keep as many teeth as possible in mesh and avoid slipping of the belt. The higher the load on the belt, the higher the pre-tension (and width of belt). These effects are taken into consideration in the calculations, should be at least, that is the problem with such design tools, you can't be sure what it is doing in fact.
Gates' tool (called design flex pro iirc) for example also offers the possibility to distinguish between constant and periodic/intermittent loads, thus reducing the maximum transferrable power by 50-100%.

That is also the main concern I have about grease or oil in there, reducing friction in critical situations, like insufficient tension plus a torque impulse or resonance effects.