samarium cobalt brushless motors

I'm wondering if anyone has used these motors for electric outboard.

The reason is, say a motor is designed 95% efficiency at 1kw. Then with neodymium magnets, the thing can't even operate at 2kw sustained without destroying the magnets, however with samarium cobalt magnets it could operate at 3kw (even much more power) at reduced efficiency 85-90%. Useful say to get through an atoll pass or something.

Then in bursts it could operate even stronger perhaps 10kw for 30 seconds in extreme cases (you ran aground or something)

Sure you could just use a larger motor too. In the case where you dont want a lot of weight, and nominally operate at efficient speeds, but wanted such power available in extreme cases, would it not make sense to trade the 1-3% efficiency at nominal speed (neodymium is slightly more efficient when running cool) to have potentially much higher power density, and potentially longer lasting motor.

Also a similarly premium to wind it with silver wire as well. Since the motor itself could be 1kg and 2kw nominal output 3210 ASTRO BRUSHLESS MOTOR https://www.astroflight.com/3210-astro-brushless-motor.html the cost of silver is only about $300 for that motor and gives 7% better conduction, and 7% better heat transfer so overall 12-15% better power density and higher efficiency.

 

Typically motors have a continuous duty/output rating and a peak that is sustainable for a short period of time due to heat as you have pointed out.

Moat of the consumer electric propulsion motor manufactures error on the side of caution and design around the continuous rating. sometimes more conservatively so due to the wide range of applications and use (lightweight small displacement boat, kayak, heavy displacement sailboat, etc..)

A few manufactures however have designed their products to take advantage of peak performance for the very reasons you suggest by offering a “boost” mode that allows higher output for a short period of time.

An example is EPropulsion’s ELite which is a motor that runs 500W continuous but will boost its output to 750W for one minute and then default back to continuous.

I have one of these motors and have found the feature to be quite useful when maneuvering my Trimaran into the wind and through a river mouth.

Since I leave the motor fixed and use the rudder for maneuvering, the more speed and water flow, the more effective the rudder, so a 50% increase in power input for a minute can be a handy thing.

Anyway, I think most manufacturers don’t bother to take advantage of peak power because it adds complication to the controller and because most are focused on range and runtime which is still the main gripe many have with electric propulsion.

I think Golden Motors might also have a boost feature on some of their electric outboards, and the new Remigo offering may have something as well.

 

sure boost of 150% or even 200% is possible with neodymium, but with samarium cobolt, continuous 300% is possible, it just reduces efficiency and boost of 5x for bursts. This is a completely different class.

I am talking electric outboard with 5kw boost power, 3kw continuous, and 1kw efficient output with motor weight 1kg.

 

I didn’t say it was in the same class, just pointing out the feature already exists at a lower scale for the reasons you suggested, and that many manufacturers could take advantage of it, but don’t.

What you are proposing is a boutique product.

There’s lots of technology that could be adopted by the industry that hasn’t yet been.

Most are still just copying each other and looking to cut cost as much as possible to match or beat competitor pricing.

Using better materials and components to make a better product is a rarity these days, especially if someone else hasn’t already proven the market space.

What do you think will happen when you increase power that much turning a prop that is optimized for efficient performance at continuous power levels?

From personal experience, the biggest problem with a “boost” feature is once you use boost mode, you wish you could operate the motor at that power level continuously

 

Some induction Motors can reach very high efficiency and are being investigated for use in electric cars. They don't use magnets which means they don't depend on Rare Earth elements, and might cost a lot less compared to the magnet type? But I don't know if they can be scaled down to smaller sizes and keep that efficiency..

induction motor efficiency chart at DuckDuckGo https://duckduckgo.com/?q=induction+motor+efficiency+chart&t=h_&ia=images&iax=images&iai=https%3A%2F%2Fwww.mdpi.com%2Fenergies%2Fenergies-15-02002%2Farticle_deploy%2Fhtml%2Fimages%2Fenergies-15-02002-g019.png

A large industrial motor was recently built in India with a record over 99% efficiency.

Metal belt Transmissions perhaps can be used to keep
induction Motors near their Peak parameters, and lessen the impact when they are run in the less efficient range.