| > I am thinking of using a 3 phase 7.5kW 2840 rpm motor to power a bow | > thruster propeller as my generator has a 3 phase output and can accept | > loads up to 8kW using starting and running capacitors. It should also | > be simpler than a hydraulic installation. When started it will be | > against a stationary propeller - so I am hoping to be able to use a | > DOL system so that I do not have starting delays. | >
| > Grateful for any advice on pitfalls etc. | | Rob, one of the many reasons that hydraulics are used on bow thrusters, and | other auxilliary machinery, is that the motor only needs to be started | once - whilst you're still tied up. | | No matter how you start it, a motor that size will cause your genny to | strain a little on startup (due to very high inrush currents), and then | there is the possibility of the motor stalling out the generator just when | you need it most (ie. whilst manuvering). | | If you *really* want to go electric, you might like to install another | generator (a dedicated one just for the thruster woud be nice.. :-) | | Cameron:-) |
Ditto for Cameron's comments. and you might also consider the use of a small Variable Speed drive. THis will eliminate the starting unrush currents as well as giving you a little more control over the amount of thrust you are applying to the bow.
I am not a "Boat Man" So am not really sure if variable thrust at the bow is a desirable thing or not.