In the University of Canterbury document the nominal engine speed is given as approximately 2000rpm and the fan speed as approximately 360rpm.
In the Defender/FMR advertising the gear drives that are reported for the upper and lower gears are UD105 and W85 respectively.
So here's the deal. The ratios specified for the gears on the Amarillo web page are 1.64:1 for the UD105 and 2.25:1 for the W85.
And so in theory 2000/(1.64x2.25) should equal 360 if both the UoC and FMR Advertising were talking about the same product.
But it doesn't.
FMR are either still peddling the same specifications for the Amarillo in the Defender advertising or the University of Canterbury are having problems with an equation that a 9 year old could get right. I'm picking that the FMR advertising bureau have covered themselves in glory once again.
This wouldn't be too bad, but as part of checking compliance of these machines, one of the methods is to measure the speed of the engine with a tachometer and to calculate the fan speed from the supplied gear ratios. It's not going to be a pretty sight if the calculation for a Defender fan shows it to be turning at 542rpm. Not pretty at all.
But wait!!
It get's more interesting.
On the same web page that provides the gear ratios, is a small note near the bottom that talks about the electric powered wind machines. A UD105E, of which there is a variant that is exported for use on 50 Hz systems, has a ratio of 2.47:1.
And guess what?
2000/(2.47x2.25) equals 360. Which would be correct according to the UoC figures. So I'm going to presume that in spite of what the Defender advertising says, the University of Canterbury figures are correct and that the model of upper gear used in the Defender is the export model UD105E.
Now this might all seem like nit picking at the expense of a company that is more interested in a glossy brochure than the accuracy of the figures in it, but there is a slightly more worrying side.
The Amarillo gear company are justifiably proud of their sturdy gears. So much so that they specify their mechanical rating for both the UD105 and the W85. And both of these units are used in the Amarillo frost fan which is rated at 125HP at the fan.
But the electric powered fans are a different kettle of fish. They are rated at either 100, 75 or 50hp at the fan. And as a result the mechanical rating of the gears can afford to be less.
So what would happen to a gear that is rated for a light load on a frost fan designed to run electrically when it is used in a diesel powered fan which runs at a heavier load? What is the subsequent load when the thrust of the fan is increased when a larger fan is put on the tower?
I'm sure all these trifling mechanical matters have been carefully considered by the manufacturer and that they have sought the advice of the parts suppliers in making sure that the device is safe for use. I mean, that would be the responsible thing wouldn't it?
5 comments:
What a pity you can't do YOUR homework properly. The top gearbox on a Defender wind machine is not 1:1.64. Even if you were half as intelligent as you think you are, you would spend more time getting detail correct before rushing to print.
The history of advertising and noise testing of Amarillo Frost fans by FMR is a sad tale,where "buyer beware" rings loud. Eventually the chickens will come home to roost,it may be sooner than later. A large proportion of the two blade 1200 'odd' machines in Marlborough will have to be replaced as the reality will have to match the propaganda. The MDCouncil is gaining the technology and will, to assess machine noise from a distance. Frost protection will have to be accomplished below the noise limits in the District Rules.
Err... Thanks Anonymous. Actually you and I agree. Since my only source is the advertising published by FMR that specifies the gear box used (see the post again), I can only go on that. I'm sure you see how confusing this could be for prospective buyers. One day I hope to be 1.64 times as smart as an advertising weenie. But if I'm only half as smart as I think I am at the time I still don't think I'll make par.
Are they now getting into turbo fans? This should be a great idea as they will need fewer of them as they will do several neighbours vineyards and much more quietly, right? Perhaps they could just look into old jet engines and use them.
Now just be careful. You may think you're jesting about jet engines, but I have seen pictures of a device that could only be described as the evil love child of a frost fan and a cluster of large blow-torches. I am not joking.
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