Excited to join this forum. I have a question that motor manufacturers have been tactfully avoiding and I want to know if it is an ignorant question to ask, or if they just don't want to spend the money, or if its just unnecessary.
I have a Motenergy ME1305 5kW PMAC motor and a Sevcon Gen4 size 2 controller on 48VDC in an small electric boat, inboard drive with V belt 2.8:1 gear reduction. It is a highly efficient system driving a 12" three bladed propeller of uncertain pitch and EAR. The boat is a displacement hull and 16.5' water line length, hull speed is about 6mph.
The current gear reduction and propeller configuration requires the motor to run at 1500RPM at 1kW input power, achieving 5.5mph and 170MPGe (0.2kWh/mi). This motor speed is well below the motor's performance chart:
I can see that the 48V efficiency curve of this motor peaks at the 3250RPM range, but this shows performance at full load of course.
So my question is, I need 1 to 2kW at cruising speeds, what is the most efficient motor speed to do this at? I want to adjust my gear ratios to optimize efficiency.
I asked Motenergy for a motor efficiency contour, but was told that was too expensive to run a test like this: https://www.researchgate.net/figure/224 ... tion-motor
I really wanted a torque/speed plot that shows shades efficiency like above. The regular "dyno chart" these motors come with really just shows me the top end of the motor RPM range where torque is dropping off fast.
Thanks for any advice.