Narrowboat Electric Motor Test - Mothership vs Vetus

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Mothership Marine have been designing and building electric propulsion systems since 2016. On the waterways there are 2 main types of electric motor.
1. AC Induction Motor
2. PMAC Motor (Permanent Magnet AC Motor)
Of the 2 Mothership Marine prefer the PMAC motor. Here's why. Permanent Magnet AC Motors (PMACs) stand out as superior choices for marine propulsion due to their exceptional reliability and efficiency.
The motor consists of two key components: the rotor and the stator. The rotor, connected to the propeller, features permanent magnets typically made of rare-earth metals. These magnets react to the magnetic field generated by the stationary stator, which surrounds the rotor. The stator contains electromagnets powered by an AC current.
The AC current is produced by the motor controller which converts DC current (from the boat’s batteries) to 3 phase AC current and when introduced into the electromagnets causes the rotor to rotate.
PMACs offer several advantages for marine applications:
1. Efficiency: PMACs excel in efficiency as the rotor and stator interact solely through a magnetic field, eliminating friction and reducing wasted energy. The AC signal further enhances efficiency, ensuring smooth transitions between electromagnetic coils for a continuous, efficient rotation.
2. Low Wear and Tear: Labeled as "zero maintenance" motors, PMACs do not require extensive lubrication, ensuring high reliability and longevity. This contrasts with brushed motors that suffer from contact points wearing out over time.
3. Low Noise: PMACs operate quietly by avoiding excess friction and jittery rotor rotation, making them one of the quietest motor types.
4. Power Density: The efficiency of PMAC motors translates into higher power output or a smaller form factor, offering superior power density compared to other motor types.

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Опубликовано:

15 фев 2024

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Комментарии : 14

@trevorsbarkingmadchannel4501 4 месяца назад

Love it. Very interesting indeed. Very into evs. Would love to have an ev narrowboat. Keep the vlogs coming pls. Best wishes.

@mothership_marine 4 месяца назад

Thank you! Will do!

@ajw1467 2 месяца назад

very intresting coming from both a boat builder as trade and a commercial fisherman i wonder if a type of kotz nozzle would improve even more ?

@mothership_marine 2 месяца назад

You might have point. I know they are widely used on tugs. Ii guess trawlers are kind of tugs. I’ll take it up with our prop manufacturer. Cheers Tim

@mothership_marine 2 месяца назад

Good point. I know they are use widely on tugs. I guess a trawler is a tug. I’ll take it up with our prop manufacturer. Cheers Tim

@clivestainlesssteelwomble7665 29 дней назад

Generally an enclosed prop is more efficient and powerful up to a key speed .. I've seen data relating to rim driven blade... motors and they claimed that the speed limits with motors this size was about ten knots. Not a problem for a waterways boat plus the rim driven designs allow debris and weeds to pass through the center.. the individual blades can be swapped out and self trimming. RM and DeepBlue plus another french group all produce these sort of units. There's also an outboard producer who adds a nozel impeller .. to prevent tip spill and maintain better flow over the blades. There is a sea going cat cruiser called the Earthling E 40 from Australia it's built around efficiency at 10kn cruising it's an E powered hybrid electric system. It's props are huge scimitar form multiblade items.

@sunlightconversions828 4 месяца назад

100% with you on the advantages of a large slow spinning prop. That's what I always aim for. Is there a direct correlation between thrust and efficiency? If so the MS is about 50% more efficient. Thats what I can't wrap my head around.

@mothership_marine 4 месяца назад

Hi there and thanks for getting in touch and your kind comments. Our simple test on the marina compared thrust (pull), measured in kgs, to the power drawn by the motor measured as kW. The Mothership motor and prop use much less power to achieve the same pull as the Vetus motor. So yes our set up was shown to be more efficient. The hulls were different but not massively and the weather did vary a little too. To say that we are 50% more efficient is a big claim and the experiment was not in a lab under lab conditions so I’d just prefer to say the Mothership setup is ‘more’ efficient. But where every watt is valuable these things are important. Here’s a nice experiment to get you thinking. it’s on a model airplane motor www.tytorobotics.com/blogs/articles/how-to-measure-brushless-motor-and-propeller-efficiency

@robinbennett5994 3 месяца назад

The maths is fairly simple, GCSE-physics-level: a 13" prop is only pushing a 'tube' of water with about 40% of the cross section, so it has to push it more than twice as fast to get the same thrust. However while momentum scales linearly, the kinetic energy in the water scales with the square of the speed. So the smaller prop should require twice as much power for the same thrust. The interesting thing here is that this matches the experiment at the higher power settings, but at the lowest power setting they were much closer. That implies that at very low power the smaller prop might even have been more efficient. Possibly there's more skin friction with the bigger blades, or the speed controller is less efficient when running at an extremely low setting.

@mothership_marine 3 месяца назад

Hi Robin, I think of a propeller more as a screw rather than a jet. The more traction is has the better it performes. Big ships have huge props that revolve only about 150 times a minute. Slip is only a few percent which shows this setup is very efficient. Cheers Tim

@alecfowler667 4 месяца назад

Hi was interested by this video. As I think comparisons are good. BUT sorry I couldn’t see the direct comparison. Any test should surely be on a level playing field. To do this perimeters must be known. So are the hulls identical as this would affect the water to the prop. When using a kg loading, on a strap tied to the bank ( not highly scientific or representative as I’m sure the marine world in general don’t use this as there standard test) was the wind in the same direction and at the same strength, what was the comparative weight of each vessel. You talk about large to small prop comparisons but you don’t go into usable distance ie how far can you go on a charge. They don’t put big tyres on EV cars as rolling resistance is detrimental to battery life. Having read into the the Vetus Eline you are incorrect that it is air cooled. The motor controller is water cooled as it is pointless cooling the windings as the temperature they can run to is well beyond anything that the motor will produce in an open engine room and if it did hit higher temperatures the motor would derated till normal temperature is achieved which will be minutes. The point being is anything can be over engineered but it drives the cost up, whereas correct design and R&D testing means the best solution for the purpose intended at the most competitive price, also meaning less resources, are used driving up its ecological credentials. I think in general terms what is most important to the end user is longevity of cruising time against the recharge time when choosing an EV propulsion system, but you studiously ignored those factors which was highly disappointing. So when I was suggested this video to make comparison based choices it was hugely disappointing.I do personally feel this is solely a poorly done sales pitch, lacking in substance, scientific knowledge, understanding of the EV market and the requirements of the end user. I wish it had given me more knowledge to make an informed choice, instead I feel I got a poorly pitched sales video shoddily produced, and using the rank of a chief engineer to give it a whiff of credibility.

@mothership_marine 4 месяца назад

Thank you @alecfowler667 for getting in touch. Initially I’d like to point our my experience and that of Martin in the Merchant Navy. Martin’s experience is more relevant as he was a Chief Engineer, I was a Deck Officer. Bollard test are fairly common place in the marine world - please see this example on youtube ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-Pkq9X2sOrps.html You’re right this was more of a practical demonstration rather than a scientific experiment but if we ignore figures over 10kW the data is very convincing. 1kW Mothership 40.5kg - Vetus 38.5kg 2kW Mothership 78.5kg - Vetus 53.5kg 3kW Mothership 105.0kg - Vetus 70.0kg 5kW Mothership 155.0kg - Vetus 100.5kg 7kW Mothership 190.5kg - Vetus 135.5kg 10kW Mothership 259.0kg - Vetus 161.5kg The Vetus e-line does have water-cooling elements fixed to the motor’s casing. These only have contact with a small proportion of the available surface. There is also an air fan fixed to the front of the motor. There is a loverly saying ‘Engineers do the same as anyone else but for half the price’. The Mothership Tidal Motor is built to our specification in Europe. When I commission them and they go through their set-up sequence, I’m in awe of the power, they just purr. They really are a thing of beauty. Vetus is a reputable company and I’ve been using their products for years (not motors) however they have big overheads and spend tons on marketing. Mothership are a small team of 6 employees with a few specialist consultants pitching in. Our overheads are minuscule and our product very niche. It’s how we are able to offer a superior product at a good price. I personally think that the Vetus motors are designed for small launches. Here we are David and Vetus is Goliath. Yes this was a sales pitch by demonstration. And if I had Vetus’s resources I would advertise extensively, have a large sales force and exhibit at great cost in every exhibition. We have a lot to be proud of. But for the moment RU-vid will have to do. Tim (aka David)

@user-iw8cn5mb1c 4 месяца назад

What a surprise: "We from Mothership advise Mothership". Comparing a 10Kw with a 15Kw is like doing a drag race with a VW Golf and a Ferrari. A 50% power difference ! The only difference in the 5 points mentioned in the text above compared to an induction motor, is the efficiency. A PM motor usually has a better efficiency compared to an induction motor. There also is a little price difference in between the 2. Correct? Using an already switched of power mode on the Vetus E-line, does indeed deliver less power. The conclusion about the RPM is a complete misconception. For cooling purposes? 🙂 The intention of this test was good, however doesn't serve a purpose due to the big differences. Perhaps Vetus next time can compare a 15Kw Mothership with the upcoming Vetus 20Kw? Or do the test together with Mothership to make sure things match up? Next time please do better.

@mothership_marine 4 месяца назад

Thank you user-iw8cn5mb1c for getting in touch. I do not wish to be arguing with fellow electric boaters (assuming that you are). I think that we should all be on the same side. I’d also like to ignore the fact that the Mothership Tidal Motor is capable of 15kW because because most of the time narrow boaters will find that they will be quite happy with around 1kW. Where is the power going to come from after all? At Crick 2019 I was asked by potential customers ifl our motors cope with a strong river flow or tide. Always one to rise to a challenge, I ended up on the River Thames with the Editor and Technical Writer of Waterways World mothershipmarine.com/about-us/press/. Just downstream of the Houses of Parliament I needed 7kW for about 5 minutes. I had our smaller belt drive motor fitted to Shine then and the motor temperature rose to 90 degrees centigrade. That was a belt drive motor, air cooled. That experience prompted the Mothership Tidal Motor. The real point of our test last year was to show the efficiency benefits of having a larger propeller. Vetus I understand recoment a 13" prop, we recoment and 18" or 20". The conclusion being that, motors that have the guts to drive larger propellers offer a more efficient solution for narrowboat propulsion. Ignoring figures over 10kW the data is very convincing. 1kW Mothership 40.5kg - Vetus 38.5kg 2kW Mothership 78.5kg - Vetus 53.5kg 3kW Mothership 105.0kg - Vetus 70.0kg 5kW Mothership 155.0kg - Vetus 100.5kg 7kW Mothership 190.5kg - Vetus 135.5kg 10kW Mothership 259.0kg - Vetus 161.5kg All the best Tim