my boat motor (input wanted on electric motor, variable speed drive, 6.5kva genset)

[colfar2]

Morning all
Am building a russian design boat here in Africa and my plan for engine is a 1.1kW electric motor controlled by a variable speed drive that will get power from a 6.5kva genset. Advantages I see are eliminating a gearbox as you have forward and reverse on the speed drive .

[colfar2]

Just curios as to what people think of my idea my main issue I have is will the electronic components stand up to the elements

[philSweet]

There is an electric boat forum at Yahoo Groups that might get you a better audience. Would need to know AC or DC and the sort of controller you had in mind.

[Stumble]

It a highly inefficient way to power a boat, but it will work. And why run a generator that much larger than the drive motor? A 1kw motor will need a 1kw generator (minus some efficient loss) to operate, no reason to go to a 6.5.

[colfar2]

Thanks gents
Am going for lager genset purely to run other tools on boat .it will be AC speed drive 220v in and 220v out and main reason I am doing that is if drive packs up I will have bypass switch so I can still motor and if all systems fail I have a small 2 stroke outboard

[fredrosse]

A 5kW generator can just barely start a 1.1kW motor. Once the motor is up and running, it will consume about 1.1kW, but on starting it needs about 5kW, and if the generator isn't up to the task the breakers will trip, or the generator may be damaged.

There are electric arrangements whereby a motor can be "soft started", these switching schemes were usually used in factories where the electric supply system was inadequatte for starting very large motors. I think this complication is a difficulty you do not want to face.

One option that might be considered is a DC system with batteries. This works well for many boats, and could use a DC generator (or an AC Genset with separate charger) to continuously charge the batteries while underway. It also allows limited travel on the batteries alone.

Power inverters that convert DC to AC are available and work well. When I was having an addition put on the house, the electricians had to shut down power for a day, and I wanted AC for the carpenters who were still at work. I hooked up a 2200 watt inverter to the battery pack in my boat, and kept the project going all day. The inverter started the 12 inch chop saw (and skill saws, etc) all day long.

Going to IC-Electric drive seems to be much more work than its worth, but is feasable so long as the starting loads are considered.

[mydauphin]

Originally Posted by philSweet

There is an electric boat forum at Yahoo Groups that might get you a better audience. Would need to know AC or DC and the sort of controller you had in mind.

Yeah, people here actually know what it takes to push a boat. Most people talking about these hybrid ideas are clueless as to what they need, and others are trying to scam others. Is it possible? Sure, if you have the money. But when you run out of juice or don't have the horsepower to fight a current your going to need a tow from a regular boat.

[mydauphin]

Originally Posted by colfar2

Morning all
Am building a russian design boat here in Africa and my plan for engine is a 1.1kW electric motor controlled by a variable speed drive that will get power from a 6.5kva genset. Advantages I see are eliminating a gearbox as you have forward and reverse on the speed drive .

What size boat?

[colfar2]

Morning

Boat is 8.5 meter long and can be seen on this forum under my russian boat. Am currently testing my design at work with a 6.5kva genset and a 2.2 kW Emerson frequncy drive and it does work .
My next step Is to put it in a tank of water to see what sort of torque it puts out .. A lot of people have exspressed there concern about wheter it will be able to handle a strong current and I have the same concern .the boat will be going to a dam first to see how it copes