Now this is only a thought. 230vAC from 30HPengine

stuhaynes

stuhaynes

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Now this is only a thought. 230vAC from 30HP engine

30 HP @ 2000RPM max., cruising, say 1500 RPM Single 'V' pulley. 4 cylinder diesel.

What are the options for a 230 volt AC generator including min cost of equipment?

I'm not looking at this too seriously, I just wonder.. What are the dynamics of, say for instance, something that can produce 3.5KW to run maybe a washing machine or 1KW immersion heater or a standard electric kettle? Though not all at the same time...... Just curious :confused: I'm pretty sure that a single 'V' pulley drive won't hack it.

Given the use of our current boat, this is not a necessity, but if we change our boating patterns, which is possible, we may be glad to be prepared to use the engine to provide our 230 volt needs. We have a 1500 watt inverter, but only 4 'house' batteries, wired to provide 220AH (@24 volts). As has been said to me before in a previous question, this is nowhere near enough. We don't have space to place more than 2 more batteries max., and that is still not enough..even if the inverter was. Our alternator is 60 amps max and 24 volts, if that has any relevance.
 
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A single V belt will be no where near enough to transmit 3.5 kW



If you run an AC generator from the engine you will have to bear in mind the frequency.
For UK appliances using motors etc you will probably have to keep it somewhere around the 50Hz mark. No problem I guess for heaters etc.
 
AC alternator

I tend to agree that an AC alternator driven by the engine could be ideal.
I had an aquaintance long ago who did this on his engine apparently successfully. He used an airconditioner type DC powered clutch to the pulley to make it possible to switch it on and off.
As Vic says frequency is quite critical most gens will need 1500 RPM to produce 50 hertz. Or it might need 3000RPM if single pole design. You would need to be satisfied with the chosen engine speed depending on pulley ratios for motoring and the same speed for idling/power generation.
Theoreticlly 650 watts equals 1 HP `so in practice 5KW will suck about 10 HP and so need to be transmitted via the pulleys and belts unless you go direct coupling.
good luck olewill
 
AC generators need precise engine speed. What you need is a big DC alternator and an inverter.

3.5kW is asking a lot. I get about 2 practical kW out of my setup - 110 amps x 24v alternator, 3kW Victron inverter. The inverter will add battery power to cover short term loads up to 5kW. It will run a washing machine.

I have dual belts. An alternator that size also needs plenty of fresh air for cooling.
 
We have a Nanni inline generator and get 4 kw at any power setting of at least 1400 rpm. I know nothing is free, but there is no discernible loss of engine thrust with the generator running, so it feels like it is for free!
 
stuhaynes said:
30 HP @ 2000RPM max., cruising, say 1500 RPM Single 'V' pulley. 4 cylinder diesel.

What are the options for a 230 volt AC generator including min cost of equipment?
Click to expand...
New Beta 35 with the Travel Power unit at the foot of this page ?

Not most people's definition of "min cost" though. :rolleyes:

Boo2
 
To answer your question directly: No Way

I had a 5KW SeaPower system fitted to my 50Hp Beta and it needed 2 'B' type belts to run it. Not only that, but the crankshaft pulley was 10" diameter. Another challenge.

The SeaPower (now defunct) or Dometic Travel power units use a 3 phase alternator at 240V - the only practical way to get power in a small space - which is rectified and converted to stable 50Hz 240V AC. Seems like an elegant solution, but apart from the high cost they are not hugely reliable.

I think you should consider fitting a beefed up alternator possibly with an Adverc / Sterling controller system and an uprated inverter. Much cheaper.

It was the solution proposed by Charles Sterling as a better way to do it - so that's probably a kiss of death.....
 
TrueBlue said:
To answer your question directly: No Way

I had a 5KW SeaPower system fitted to my 50Hp Beta and it needed 2 'B' type belts to run it. Not only that, but the crankshaft pulley was 10" diameter. Another challenge.

The SeaPower (now defunct) or Dometic Travel power units use a 3 phase alternator at 240V - the only practical way to get power in a small space - which is rectified and converted to stable 50Hz 240V AC. Seems like an elegant solution, but apart from the high cost they are not hugely reliable.

I think you should consider fitting a beefed up alternator possibly with an Adverc / Sterling controller system and an uprated inverter. Much cheaper.

It was the solution proposed by Charles Sterling as a better way to do it - so that's probably a kiss of death.....
Click to expand...

Thanks everyone, I thought that it would be a problem. I'm not too concerned because we have shore power most of the time. It's the old story about self sufficiency. Thinking about it though, even if we were to take an extended trip the only real problem would be washing clothes. We'll just have to find a laundrette! :eek:

Thanks everyone
 
TrueBlue said:
I think you should consider fitting a beefed up alternator possibly with an Adverc / Sterling controller system and an uprated inverter. Much cheaper.
Click to expand...
Well, 3500W is 257A at 13.6V so that's a bigger alternator than I've heard of being fitted to a 30hp diesel. Though in truth, what I've heard about the reliability of the Travel Power units doesn't inspire much confidence, especially given the £3k5+ price...

Boo2
 
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Boo2 said:
Well, 3500W is 257A at 13.6V so that's a bigger alternator than I've heard of being fitted to a 30hp diesel. Though in truth, what I've heard about the reliability of the Travel Power units doesn't inspire much confidence, especially giien the £3k5+ price...

Boo2
Click to expand...

We're 24 volts, so it's only half of that. It's still too much for our 60 amp alternator! Although it's new it doesn't even like our 1KW immersion. I did try it thinking that 42 amps might not be out of the question, but stopped because it got very hot, very quickly. I plumbed the engine in instead which was the advice I got here in a previous thread.

A definite no-go I think. :(
 
stuhaynes said:
30 HP @ 2000RPM max., cruising, say 1500 RPM Single 'V' pulley. 4 cylinder diesel.

What are the options for a 230 volt AC generator including min cost of equipment?

I'm not looking at this too seriously, I just wonder.. What are the dynamics of, say for instance, something that can produce 3.5KW to run maybe a washing machine or 1KW immersion heater or a standard electric kettle? Though not all at the same time...... Just curious :confused: I'm pretty sure that a single 'V' pulley drive won't hack it.

Given the use of our current boat, this is not a necessity, but if we change our boating patterns, which is possible, we may be glad to be prepared to use the engine to provide our 230 volt needs. We have a 1500 watt inverter, but only 4 'house' batteries, wired to provide 220AH (@24 volts). As has been said to me before in a previous question, this is nowhere near enough. We don't have space to place more than 2 more batteries max., and that is still not enough..even if the inverter was. Our alternator is 60 amps max and 24 volts, if that has any relevance.
Click to expand...

Machine Mart stock 240v alternators eg http://www.machinemart.co.uk/shop/product/details/3-5kva-3000rpm-alternator

With some work, one could be driven at 2:1 to keep the engine rpm down to 1500 provided you can fit an adequate belt drive system and ideally a clutch.
 
ianj99 said:
Machine Mart stock 240v alternators eg http://www.machinemart.co.uk/shop/product/details/3-5kva-3000rpm-alternator

With some work, one could be driven at 2:1 to keep the engine rpm down to 1500 provided you can fit an adequate belt drive system and ideally a clutch.
Click to expand...

Thank you for this reply. It does raise an interesting question for me though.

1. From past experience I really do not trust Machinemart. I remember, from my long past motor trade days, their cheap cr*ppy compressors were just that. In those days it used to be made in Italy.com (as opposed to AliBaba.com)((as agents of those who must not be named because of UK/Sino relations))

2. The Hz thing. I want 50, not 60 or more (or less). If the cr*pmart alternator requires 3000 rpm (to provide 50Hz) and the boat engine (because of pulley gearing) provides more or less revs than that whilst travelling, what happens to the Hz?

I suppose that what I am asking is...... To produce 230AC @ 50 Hertz, is it necessary that the 230 volt alternator turns at a specific RPM. I suspect that this is true, but I honestly don't know.

Hmmm. Ive used more brackets than Hinge and Co. Mmmm. :rolleyes:
 
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Alternator speed and frequency

The 3000 RPM is a function of 50 turns per second so 50 hertz AC. The AC cycle is produced magnetically by the rotor turning a full circle. So for all alternators the speed dictates the frequency. However this does guarantee a good sine wave AC.
The alternative on some modern small alternators is that the alternator generates AC at any frequency depending on engine speed and load. This is rectified to DC then inverted to "make" AC. The made AC being more often like an inverter off a battery not a good sine wave. (so not good for AC induction motors.

My guess is that for most purposes a 10% accuracy of engine speed will suffice. So 1500 RPM engine speed requires between 1350 and 1650 RPM. Any more variation and some induction motors will lose power and get hot. Like a fridge motor. An imersion heater won't care what frequency. A microwave oven will have an inaccurate clock and timing with inaccurate frequency. I suspect your washing machine also will have inaccurate cycle timing and possibly overheating at wrong frequency.

What you want then is some sort of electronic device which will determine engine speed and only allow alternator electric clutch to operate if the engine speed is close to correct. A governor would help a lot of course. I would imagine that you could choose an engine speed that is fast enough for cruise motoring but not too fast for idle/ engine run for power. Unless you chose only to run the alternator when idling (just above idle speed). Engine speed to get 3000 RPM alternator speed is done by pulley ratios. I think the alternators in the link would be really excellent for the purpose.
Certainly far better than a huge 12v alternator huge batteries cabling and inverter. good luck olewill
 
stuhaynes said:
Thank you for this reply. It does raise an interesting question for me though.

1. From past experience I really do not trust Machinemart. I remember, from my long past motor trade days, their cheap cr*ppy compressors were just that. In those days it used to be made in Italy.com (as opposed to AliBaba.com)((as agents of those who must not be named because of UK/Sino relations))

2. The Hz thing. I want 50, not 60 or more (or less). If the cr*pmart alternator requires 3000 rpm (to provide 50Hz) and the boat engine (because of pulley gearing) provides more or less revs than that whilst travelling, what happens to the Hz?

I suppose that what I am asking is...... To produce 230AC @ 50 Hertz, is it necessary that the 230 volt alternator turns at a specific RPM. I suspect that this is true, but I honestly don't know.

Hmmm. Ive used more brackets than Hinge and Co. Mmmm. :rolleyes:
Click to expand...

You need to spin the alternator at 3000rpm for 50HZ, or gear it up 2:1 and run the engine at 1500, (or some other rpm with different gearing).
The rpm does therefore determine the Hz which really makes it a no go for using it whilst underway.
If you need to keep the frequency close to 50Hz, then it would prove more costly and you'd be better off with an inverter or only use frequency sensitive devices at the appropriate engine speed.
 
even if we were to take an extended trip the only real problem would be washing clothes.
Click to expand...

One of the things you learn when long-distance cruising is that you don't allow dirty clothes to accumulate - the old adage of 'one on, one off and one in the wash' applies. Most modern washing detergents work well at low temperatures, so a boiled kettle is enough to do your day's underwear and 'T' shirt in a few minutes with a hot, detergent wash and a cold rinse. You can also do equally well by taking a shower and washing your clothes at the same time. You don't need a washing machine!
 
if dabbling with the idea of 240v AC on board while at anchor (not marina) I suppose that one solution would be to go to the main engine being a proper 240v 50Hz generator, feeding the domestic supply OR an electric motor for the prop.

Engine then would be precisely governed for RPM, and you would not be able to use the washing machine while under way.
 
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