Best place to buy Spindle and VFD?

[Kitwn]

Oooops!
That should have been 30l/hour. 500ml/min which didn't seem like much to me at the time, especially as I'd measured 4 times that with a short 250mm stub of the 5mm tube from the same pump.
I have no problem with your calorific maths, it all looks fine to me.

One thing I do, which I think we exchanged some comments on in the 'plumbing...' thread I mentioned above, is leave the pump running continuosly when the VFD is switched on. This ensures the bearings get maximum cooling between sucessive jobs. This is done to avoid the 'Perth Transformer Effect'. A few years back I worked for the WA power utility company. If we had a sudden spell of hot days in summer there would be a rash of transformer failures on the third day...Maximum load is around 4pm when everyone gets home from work ( we tend to work 7 - 3:30 over here) and switches on their air-con. The transformers heat up on day one and cool down overnight, but start day two hotter than they started day one. Day two follows the same pattern. On day three the starting temperature is so high that by early evening there are plenty lof angry, sweaty poeple around and plenty of power company workers missing dinner but earning lots of overtime replacing burst transformers. That was a massive problem in 2003-4-5 with everybody fitting the ever-cheaper but more power-hungry refrigerative air-conditioning and peak demand changed from heating in winter to cooling in summer.

Kit

PS You never know what you might learn reading MYCNCUK!

[Neale]

Ah! That sounds better! And I would agree that 0.5l/min seems a little on the low side. I think a better value would be "a few" - and it's really not that critical, I would think.

Science is great for giving us some insight into what's going on, but a bit of real-world experience helps a lot - like your Perth transformer example. I always remember the story of the physicist who was asked to analyse some data to do with egg production due to his mathematical background. He came up with an answer, backed by pages of analysis and calculation, but qualified this with the proviso, "but it's only true for a ideal chicken in a vacuum!"

As for the original "where to buy?" question, though - that's in the realm of advertising and marketing hype, and no help from science there... My HY inverter and spindle came from a UK supplier who charged a bit more but reckoned that they were reselling kit from a trusted Chinese supplier. That one came with preconfigured inverter, ready to go, and it's been running for about 7 years now with no problems. I've even changed the cooling water a couple of times!

[ericks]

Ah! That sounds better! And I would agree that 0.5l/min seems a little on the low side. I think a better value would be "a few" - and it's really not that critical, I would think.

Science is great for giving us some insight into what's going on, but a bit of real-world experience helps a lot - like your Perth transformer example. I always remember the story of the physicist who was asked to analyse some data to do with egg production due to his mathematical background. He came up with an answer, backed by pages of analysis and calculation, but qualified this with the proviso, "but it's only true for a ideal chicken in a vacuum!"

As for the original "where to buy?" question, though - that's in the realm of advertising and marketing hype, and no help from science there... My HY inverter and spindle came from a UK supplier who charged a bit more but reckoned that they were reselling kit from a trusted Chinese supplier. That one came with preconfigured inverter, ready to go, and it's been running for about 7 years now with no problems. I've even changed the cooling water a couple of times!

Sounds great:)

[Kitwn]

"An ideal chicken in a vacuum", I'm going to remeber that one. It's near my bedtime here, but if we're going to talk science and in view of the recent anniversary, my most startling discovery of the last month was that when the Saturn V lifted off the pad back in July 1969 it took the power equivalent to fifty-five modern diesel railway locomotives just to run the fuel pumps!!!!!
As I've always said "Rocket science isn't that complicated. It's just BIG!)

Kit