More Generating 240 Volt Ac

Q: As the last thread seemed to meander off, I thought I would start afresh. As mentioned earlier in that thread, it is very common to hang an additional 240 volt alternator onto marine engines. They are fitted and driven the same as the charging alternator. Companies Like Sterling Power should able to help. Sorry no contact details. I'll not contradict any of the experts here, I'm only stating the fact that they are readily available and commonly used on yachts (not ships). Quote from Living On Board:- http://www.livingonboats.co.uk/27/mains-electricity-onboard-boats/ 240 volt AC Alternator These devices attach to the boats main engine. They are similar to a car alternator except they produce 240 volts AC current instead of 12 volt DC current as a car does. Again, these come in different outputs to suit your needs but remember power is only generated when the boats main engine is running. If your mooring dries out at low tide this could be a problem. I've since found that the engine must be set to run at a certain revs to give 50Hz. If the alternator needs 3000rpm then a smaller pulley on the engine end will mean the engine only has to run at low speed to provide the correct Hz. (Still can't find who sells them though). Apparently there was a US version that controlled itself at any speed, but it wasn't reliable! But after all this it seems that this may not be ideal for water wheel design after all!

A: Water wheels are reasonably constant in speed because the mill pond will have a weir with a 'gate' that allows the level to be regulated, and you're going to need some sort of gear box or heavy duty clutch between the generator and the wheel or any problems will tend to do some serious mechanical damage. I dont know if any of your saw the programmes "Its not easy being green" on BBC a year or so ago - With Dick Smallbridge. He looked into all this, and sourced a fancy alternator/dynamo/power source which he connected to a water wheel. He accepted that the power went into 12/24v batteries and then was inverted to basically light the house. He also had a wind turbine which via a battery powered a water pump to fill the cold water tank. I am no engineer, but I suspect that the OP should give up on the idea of heating water with this power, and just set up a thermostat to control a switch to power a 12V pump for the swimming pool water. Just as an aside, today was the first sunny morning (here) for a while, and our solar water heating kicked in at around 0930. Currently (midday) the panel temp is around 46C and the tank coil exit temp (roughly equals tank temp) is 40C. We've got about 8sqm of panels on the roof, but at this time of year there are long shadows across it cast by the chimney stack, so probably only about 4-6sqm actually productive for most of the morning. I don't know how much energy the pump has used - I ought to measure it really (see another thread, etc.). That's about 30 gallons worth, not counting the upper part of the tank which _may_ also have been solar heated to a similar temp (depends exactly when the rest of the family showered this morning!). It's not 'free' energy, of course, but IMHO it's paying back the investment nicely.

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