240 volt alternator

[nauticalnomad]

Has any body installed on there boat a 240Volt alternator to the engine to use the same as a generator?
There is a brand called Power-Tek which im looking for advice whether its as good as it sounds?
Mobile power vehicle mounted power solutions - Power with Unipower

[transmitterdan]

I have no direct experience with this system. The web site says it's a good alternative if you are needing a welder on board. That doesn't sound like a good thing to me. The challenges of building a robust system like this are numerous and on a salt water based platform doubly so. To get significant power from a belt driven alternator takes specialized design of the belt and pulley's and even then can put enormous stress on the engine crank shaft. If a reliable propulsion engine is any priority at all I would not consider this system. Try to find a cruiser with this system on board before going further.

[nauticalnomad]

I have spoken to a guy who used them in a fleet of ford transit vans to enable him to use mobile sprayers for spray painting cars..
Thats all. He said that they are worth the money for the power output for the 3 phase which he was requiring..

Originally Posted by transmitterdan

I have no direct experience with this system. The web site says it's a good alternative if you are needing a welder on board. That doesn't sound like a good thing to me. The challenges of building a robust system like this are numerous and on a salt water based platform doubly so. To get significant power from a belt driven alternator takes specialized design of the belt and pulley's and even then can put enormous stress on the engine crank shaft. If a reliable propulsion engine is any priority at all I would not consider this system. Try to find a cruiser with this system on board before going further.

[transmitterdan]

On a cruising boat there is no need for 3-phase power. The quality of power needed to operate an air compressor isn't that great. I would put this idea on hold until you find someone that has put a few thousand hours on one of these in a cruising or work boat. You could very easily end up with a broken crank shaft on the propulsion engine in the middle of nowhere.

[blackswan555]

Having a read "between the lines" (or the appropriate lines)

The alternator supplies the power directly to the Control Module (CM), which rectifies, controls, regulates and inverts this power to the required application.

So it is a high output alternator with an outboard regulator, Rectifier & Inverter, A modified sine wave inverter at that,,,, Hmmm
Will it work, Yes & No, Yes it probably will generate what it "says on the can" Although your engine revs may be high so fuel vs electricity generated will be poor & by the looks, There is no free-wheel type device, So you will have added engine drag all the time,
Then there's the price,,,, 3g+ Oww & take into consideration "most" boats will already have a similar system, Alt, batteries & inverter,
A longer Hmmmmm, I think I would invest in a little Honda I series gen

Tim

[RaymondR]

Farmers fit these systems onto their tractors to allow them to use power tools and weld. They use them for years without experiencing problems and it is very unlikely they would cause problems with the engine crankshaft. However if you want to run a compressor you may be better off fitting one of the ones the off-roaders fit to FWD vehicles or a belt driven truck compressor.

[transmitterdan]

Tractors have a PTO that is not directly connected to the crank shaft and usually has a dedicated transmission. That is completely different from installing a belt drive alternator on a marine propulsion engine. These engines typically do not like huge side loads on the main bearings.

[MBWhite]

Originally Posted by nauticalnomad

Has any body installed on there boat a 240Volt alternator to the engine to use the same as a generator?
There is a brand called Power-Tek which im looking for advice whether its as good as it sounds?
Mobile power vehicle mounted power solutions - Power with Unipower

Not being critical, I am just curious about what particular need you have for 240V power? As mentioned by others, things like microwave ovens and fridges can run from an inverter just fine, but if you have a need for a large and constant amount of 240V power something like this might work well, just wondering what that need would be?

[RaymondR]

Tractors have a PTO that is not directly connected to the crank shaft and usually has a dedicated transmission. That is completely different from installing a belt drive alternator on a marine propulsion engine. These engines typically do not like huge side loads on the main bearings.

A 200 amp 24V alternator pulls a couple of kilowatts at full power and these are fairly commonly run with a belt drive from the front of the engine? The system I was referring to replaces the alternator, don't know what's inside the alternator of control box which allows you to switch between mains and battery charging but since they have been around for decades suspect multiple windings in the alternator or some sort of series parallel switching of field coils. Don't know whether they supplied AC or high voltage DC; most power tools have universal motors which will work on both.

I have a 2.4KW 240V AC alternator but am switching over to a Honda electric start petrol engine on deck in a box with a 12 or 24V alternator and a rotary compressor and fitting a large capacity, sine wave inverter because I need the compressed air for maintenance on a steel boat and am sick of having to go on deck and pull the cord on the 2.4

[transmitterdan]

Your math isn't right. 200A DC at 24V is 4.8kW. Since alternators are about 80% efficient that requires about 8HP from the engine. A load that high requires a serpentine belt and even then could cause main bearing problems in a small sailboat auxiliary engine. In a boat that stays in a slip it may not be a big issue since rebuild facilities are near. But for a boat that may be in remote places it's a risk I would not take.

[Wotname]

And please remember that the frequency will be directly proportional to your engine speed. Without a governor, you will not be able to maintain a constant frequency.

For some applications (eg welding), frequency is not important but many other applications require your source to 50 or 60 Hz.

[blackswan555]

Yes on PTO type applications but the unit the OP shows uses an inverter to get it's AC, Crystal controlled frequency,

Tim

[RaymondR]

Your math isn't right. 200A DC at 24V is 4.8kW. Since alternators are about 80% efficient that requires about 8HP from the engine. A load that high requires a serpentine belt and even then could cause main bearing problems in a small sailboat auxiliary engine. In a boat that stays in a slip it may not be a big issue since rebuild facilities are near. But for a boat that may be in remote places it's a risk I would not take.

I wasn't being to pedantic with the maths but the point was that quiet hefty lateral loads are placed on engines on vehicles which rack up far more hours on the highway and as farming vehicles without causing problems to the engine.

My own engine has two alternators mounted on the same side of the engine and I average about 3,000nm per year of coastal cruising and I seldom have breakdowns and on the rare occasions I do they are generally fuel feed problems.

[sy_gilana]

My Detroit 3/53 had a 5 Kw 220v AC alternator on it when we bought the boat.
We also had an Onan genset. There was no propane/butane, and all heating was 220v. In those days (1978) Inverters were rare, so two generators were put in. There is a changeover switch, and the engine revs were dialed up by adjusting the throttle while watching the Reed type Frequency meter. It was belt driven off the crankshaft, with equal diameter double pulleys, about 12" diameter so there was enough friction. The engine had to run at 1500 rpm for 50 Hz. It worked well, but we did not need it so we gave it away, changed to gas cooking and forgot about the Lloyds 100/A1 ratings.

So to answer the OP question. Keep it clean and dry, and it will be reliable, but not economical.

[nauticalnomad]

I have found someone with a few 2 year old ones he has removed from a fleet of vans used for mobile spray painting. The business was downsized and are around the 400 gbp mark.
apparently the spec says 240 volts at 1200 RPM.
The 3 phase is changeable to single phase.

Originally Posted by blackswan555

Having a read "between the lines" (or the appropriate lines) So it is a high output alternator with an outboard regulator, Rectifier & Inverter, A modified sine wave inverter at that,,,, Hmmm
Will it work, Yes & No, Yes it probably will generate what it "says on the can" Although your engine revs may be high so fuel vs electricity generated will be poor & by the looks, There is no free-wheel type device, So you will have added engine drag all the time,
Then there's the price,,,, 3g+ Oww & take into consideration "most" boats will already have a similar system, Alt, batteries & inverter,
A longer Hmmmmm, I think I would invest in a little Honda I series gen

Tim