Replacing diesel engine with electric motor


Replacing diesel engine with electric motor

SEEKING PROJECT HELP: On an IRG boat we have a huge 450HP turbocharged diesel engine that is drastic overkill for the application, old, unreliable, expensive and has a cracked cylinder head. Time to re-power, but with what?

APPLICATION: to slowly maneuver in docking situations (infrequent) or motor-sailing. At 1,000 propeller revolutions, the propeller pushes the boat at 4 knots in light air so with confidence this would be adequate for motor-sailing or "get you home" motoring in light air. This is a sailing vessel, high acceleration or raw power to defeat currents or pound into the wind is not required.

The vessel has two AC generators which can power an electric motor:

Genset #1: 16kW, 240V, 50Hz single-phase

Genset #2: 20kW, 240V, 50Hz single-phase

If needed, both generators can be run at the same time and there is plenty of space to install two electric motors using drive belts and pulleys, but prefer a single electric motor set-up.

Power frequency and phase are important as some electric motors are sensitive to this. The motor should have these characteristics:

  1. Accept 240V @ 50 Hz single-phase
  2. Turn the prop-shaft at up to 1,200RPM (a gearbox could be added but would increase losses)
  3. Preferably (but not vital) be reversible
  4. At only 20kW a rev controller is not required, simple on-off would suffice.

We need help from someone who understands power applications to help design the basic electrics and source equipment for this application. Issues being considered include:

  • Start-up of motor
  • AC or DC motor?
  • Can the 50Hz 240V AC be rectified to drive a DC motor?

Please contact me if you can help! We are hauling the vessel out to remove the existing engine in the next 2 months.

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Latest Activity: Apr 5, 2018

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