Thanks very much to steamshovel for passing on his detailed knowledge of belt drives, which seems to confirm my own observations of the video in my earlier post - belt resonance, then belt slippage, followed by belt loss.
I also reflected that a big engine might be expected to generate 300 amps at 110 volts (typical fairground loads). That's about 55 hp, call it 65 BHP to cover belt and dynamo losses. My earlier post estimated power from what others have said to be about double that. Don't expect to overload anything by a factor of 2 without some risk to life and limb.
As to governors.
1 They should be used as a first line of defence against the engine racing away.
2 Once the load starts to slow the engine from it's governed speed, the test should be stopped - a simple way to estimate excessive overloading.
3 Governors do not eliminate the need for someone on the footplate to shut down manually in case of problems.
As to general safety:
1 Barriers in this instance were not adequate to the rear of the demo. and would provide no protection from flying debris.
2 The coal team were definitely in danger, but perhaps were not made aware of the danger.
3 A maximum loading must be estimated before testing starts based on the lower of engine NHP x some agreed factor OR belt width x some agreed power per inch width.
4 There seems to be a case for a "referee / safety marshall" to oversee such tests and tell others when to stop.
I'm really not against dyno testing done in a controlled and safe manner. Nor am I a safety saint - I have had too many of my own self induced stupid moments but have been lucky.
I had a p.m. this morning from another member which reads "I was there to witness it and the whole spectacle left a number of us feeling like we had witnessed a car accident or similar, it was an unpleasant experience............"
Is that how we want rallies to be?
Martin
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