Diamond Geezer Posted April 13, 2022 Share Posted April 13, 2022 Hi guys Anyone tell me why my micro tacho has been starting at 300 revs changed the battery still the same? Quote Link to comment Share on other sites More sharing options...
Alan Gorham_ Posted April 13, 2022 Share Posted April 13, 2022 Are you standing outside in open air when getting this reading or indoors especially in a room lit by fluorescent tubes? 1 Quote Link to comment Share on other sites More sharing options...
Diamond Geezer Posted April 13, 2022 Author Share Posted April 13, 2022 Inside mate Quote Link to comment Share on other sites More sharing options...
Martin Arnold 1 Posted April 13, 2022 Share Posted April 13, 2022 53 minutes ago, Diamond Geezer said: Hi guys Anyone tell me why my micro tacho has been starting at 300 revs changed the battery still the same? Yep try it outside, my tacho does the same under florescent lights Quote Link to comment Share on other sites More sharing options...
PatMc Posted April 13, 2022 Share Posted April 13, 2022 As Alan infers, you're indirectly measuring the mains frequency. The good news is that your tacho is correctly calibrated ? Quote Link to comment Share on other sites More sharing options...
Geoff S Posted April 13, 2022 Share Posted April 13, 2022 As Pat says, you've checked your tacho's calibration (assuming your mains frequency is 50Hz - it used to be varied for load shedding purposes, not sure if that's still the case). If you want to check rpm indoors, as I do with electrically powered models, then use a torch as the light source. Quote Link to comment Share on other sites More sharing options...
Nigel R Posted April 13, 2022 Share Posted April 13, 2022 49.884Hz at present Geoff. https://www.gridwatch.templar.co.uk/ 35GW demand. About 500W per person! I did read the average farm worker* can put out about 50W worth of labouring effort on a constant basis... It's as if we all wandering around with 10 servants in our pocket. * or other labourer. Quote Link to comment Share on other sites More sharing options...
Geoff S Posted April 13, 2022 Share Posted April 13, 2022 A pro cyclist can keep up about 400 watts on a climb for a while and a lot more in the last 200 metres of a sprint stage, for comparison. ? That's an interesting site. I see it doesn't include Solar as an energy source and that's what's powering my PC right now. Quote Link to comment Share on other sites More sharing options...
Frank Skilbeck Posted April 14, 2022 Share Posted April 14, 2022 Geoff, look more closely it does, Solar peaked at 4GW midday yesterday. Quote Link to comment Share on other sites More sharing options...
Christopher Wolfe Posted April 14, 2022 Share Posted April 14, 2022 I used to check my tacho by pointing it at the TV. 300 was a good number as it meant that the tacho was working and so was the TV. * chris * Quote Link to comment Share on other sites More sharing options...
Nigel Grant 1 Posted April 15, 2022 Share Posted April 15, 2022 I used my GloBee Intellitach today for the first time today after it had been in the draw, with the battery disconnected, for a few years. In bright sunlight it showed the rev's on an OS 25 at 6000 at what I thought was a fast idle and full rev's was 12K. These figures seemed high as I'm sure it used to be 3.5K and 10K. The prop was a 9.5x6 so the engine was revving flat out. When I got home I tested the tach on the only fluorescent tube left in the house and the tach read a steady 3000, as it did to with LED ceiling lights. The calibration figures in earlier posts refer to 300 so does this suggest my unit is out of calibration? I'm down here in NZ but our power is 50Hz. Quote Link to comment Share on other sites More sharing options...
jrman Posted April 15, 2022 Share Posted April 15, 2022 No it sounds OK. 50 cycles per second is 3000 revs per minute. Is the prop very shiny as sometimes reflections can give false readings. Try reading from the rear of the prop. Quote Link to comment Share on other sites More sharing options...
Nigel Grant 1 Posted April 15, 2022 Share Posted April 15, 2022 Thanks very much for confirming this for me. I have a couple of electrics and and can try it on them here at home tomorrow outside. Quote Link to comment Share on other sites More sharing options...
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