- 1936 Hoover Junior 37 - 2 Updates
- Dyson cyclone puzzle - 2 Updates
- What differentiates good audio xmfrs from bad ones? - 2 Updates
| tabbypurr@gmail.com: Jan 17 01:15PM -0800 > The other weak spot is the brushes themselves. The ends will fill up with crud and slow the spin way down. Not good. Clean everything out and make sure the brushes spin freely. And if they are 10 or more years old, simply replace them. > Peter Wieck > Melrose Park, PA Sorted! I think the main problem was a matchstick-like sliver of wood stuck in the first hose. Each time I unblocked it it quickly reblocked because of that. I also cleaned out the compacted dirt in the brush roller assembly. Cheers. We used the ancient Hoover 119 as a stopgap. Someone reckons it works better than the Dyson - they've not tried using the hose on it though lol. It has no carbon bristles left, but the plastic ones are fine. NT |
| "pfjw@aol.com" <peterwieck33@gmail.com>: Jan 18 05:31AM -0800 Ladies and Gentlemen, Boys and Girls, and Children of all ages: That ancient Hoover may pick up everything in sight. Which is then redistributed as microscopic (and often not so microscopic) dust particles throughout the entire area. "Back in the day" a 5-micron filter bag was considered remarkable. Today, HEPA level filtration is the norm. So, that Ancient Hoover may be the stuff of a Luddite's dreams - but in terms of actually catching and keeping the really nasty stuff (down to 0.3 microns) it is pretty wretched. And if a paper liner is used to 'modernize' its efficiency, the cost of operation goes way beyond that of a modern device. Note that Luddites were not against technology - just technology that rendered them obsolete. Peter Wieck Melrose Park, PA |
| tabbypurr@gmail.com: Jan 17 01:17PM -0800 On Wednesday, 16 January 2019 22:08:11 UTC, Jeff Layman wrote: > operators if you can have one of the cyclones to (a) swap with your one > or (b) try to take apart. If the cyclones have no scrap value, there > shouldn't be a reason why they won't let you take it. Sadly getting stuff from dumps has been impossible for many years here. NT |
| Jeff Layman <jmlayman@invalid.invalid>: Jan 18 08:21AM >> or (b) try to take apart. If the cyclones have no scrap value, there >> shouldn't be a reason why they won't let you take it. > Sadly getting stuff from dumps has been impossible for many years here. Really? You'll just have to get Sarah Moore involved. ;-) <https://www.bbc.co.uk/programmes/b06bhwvy> -- Jeff |
| makolber@yahoo.com: Jan 17 10:58AM -0800 > voltage, and waveform. > Thanks, > Eric Core saturation is not a function of load "TO A FIRST ORDER APPROXIMATION". Only the primary voltage matters. But to a second order, if the transformer core is near saturation unloaded, when you load the secondary, the primary current and the primary resistance will in effect LOWER the primary voltage and reduce the core saturation. So considering the second order effect of primary winding resistance, yeah, loading a transformer _may_ reduce the distortion a little. mark |
| Phil Allison <pallison49@gmail.com>: Jan 17 01:19PM -0800 > Core saturation is not a function of load "TO A FIRST ORDER APPROXIMATION". > Only the primary voltage matters. ** And of course the input frequency - the two operate in reverse proportion. > unloaded, when you load the secondary, the primary current and the > primary resistance will in effect LOWER the primary voltage and > reduce the core saturation. ** True even when the applied primary voltage has no changed one tiny bit cos it is coming form the mains supply. > So considering the second order effect of primary winding resistance, > yeah, loading a transformer _may_ reduce the distortion a little. ** With a tube amplifier, the effect can be very marked - since the voltage applied to the primary drops when a load is applied to the secondary. The source impedance of a pentode or beam tube output stage is pretty high, triodes are somewhat better. Only those amplifiers with large NFB ratios avoid the issue. ..... Phil |
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