Doubt it was the frequency diff, more to do with trying to get the same power out at less speed.
- Thread starter Cheesie
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Speed was the main thing on one job , learning as I go here, on some parts I've done the faster the part is turning the cleaner the finish
Scalarocco
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My concern about the lay shaft bearings was related to it not being a roller bearing. If oilite bushes were used on the lay shaft it may have a limiting factor. Roller bearings are less of an issue.
RWD3M
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Yes, that. The lower frequency made it run slower therefore puling more current.
I would have been sick of that job too. It is a classic job for CNC or capstan. You are never going to be competitive doing jobs better suited to those machines, on a centre lathe, and you will get fed up. I know, because I do it myself, I make stuff far better suited to a capstan on my L5. However I can make small quantities at a time, sell them and make some more, to prevent terminal boredom.
My biggest concern with overspeeding a motor, would be how old the motor is.
A modern motor should handle 50% overspeed without issue, but a motor from 30+ years ago, I'd have reservations about pushing it too far, but then I'd probably also have concerns about a VFD destroying the insulation.
A modern motor should handle 50% overspeed without issue, but a motor from 30+ years ago, I'd have reservations about pushing it too far, but then I'd probably also have concerns about a VFD destroying the insulation.
Dave-sparks
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Normally a 60Hz motor will overheat and eventually burn out on 50Hz simply because the cooling fan is now turning slower and it is not colling the motor effectively any more.
Isn't US voltage a bit lower as well?
So the combination of ~20% less cooling plus the higher voltage pushing more current through combines to overheat things.
RWD3M
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Yes, domestic voltage is 120v but I'm led to believe that a twin phase system is employed in domestic and commercial installations giving 120v phase to ground and 240v phase to phase.
I'm prepared to be corrected, but the compressor I biought was definitely a 240v single phase machine, just like this one
Edit: I didn't imagine it!
I just found this: 
Mains electricity by country - Wikipedia
Paragraph 1 refers.
Dave-sparks
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The US uses all sorts of voltages, for domestic installations it is usually 120V/240V split phase but they also commonly have 480V/277V 3 phase and 208V/120V 3 phase. Plus a whole bunch of other quirky supplies, they also have odd earthing arrangements such as corner grounded delta 3 phase, high leg delta 3 phase and other nonsense.
But yes they do have a slightly lower voltage on their nominal 240V supplies than we do on our nominal 230V supplies, which makes no sense on paper.
But in the real world the vast majority (if not all) substations in the UK are outputting 250V exactly the same as when a national standard voltage, and the national grid, was first established.
