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Thread: Maximum operation voltage for Neu 1527 2300kV competition

  1. #1
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    Default Maximum operation voltage for Neu 1527 2300kV competition

    Hi,
    I am just trying to find out what the maximum operation voltage for this motor would be.

    Does Neu give us kV values under load like Lehner or do they use no load values like all the chinese brands do?
    The Neu homepage says that the 1527 are safe up to 60.000rpm but is this the same for the competition version?
    I don't find any specific information on the competition version.
    They have slightly different kV values which indicates different magnets but this is just my guess.

    The rest is the usual math. I want to reach a certain operation speed under load (which means 3,5-3,6V/cell) and the motor should be safe in case the boat flips @ 4V/cell with a aproximately 10-15% higher kV as you see under load.
    Best Regards, Eike

  2. #2
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    Cool

    What do you intend to do with the motor? 60,000 rpm loaded is pretty useless even for SAW applications or any other competition for that matter. Will your ESC even support that rpm with a four-pole motor?

    Neu does not supply the Kv values you want. I?ve run a 3150 Kv 1521 Neu motor on 4S and at ~300-325 amps it spun 39,000 rpm. Based on that, 6S makes the most sense as a maximum voltage for your motor.




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  3. #3
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    Well sometthing similar to this:

    I know, the lake is too small for this but for some testing it is ok.

    I want 50k-55k under load which means 3,5V/cell and the kV under load. Looking at "China-kV" and also looking at Lehner motors the loaded kV is 10-15% lower then the unloaded kV so this is pure physics.

    If the boat has a blow over the rpm rises quite a bit. The batterie that just had 3,5V under load increases to 3,9-4V/cell and you have the unloaded kV of the motor. A little math:
    • 111-114% due to rising voltage from the batterie
    • 110-115% unloaded kV
    • --> 122% to 131% unloaded rpm


    When running the boat with 50-55k under load the motor should be safe up to more then 60k. This is why I ask.
    Just watch the recorded data of a logger during a bolw over. Yes, of course I do react and cut throttle but the human reaction time is quite slow.

    This is why I try to find out whether Neu gives loaded or unloaded kV values. At the moment I just read numbers but it is difficult to tell what they are worth.
    The other question is what changes Neu does for 90$ in the competition version. Do the 60k also apply for them?

    If the 60k do apply the max. rpm under load I would try would be ~46k which means I would go for different motors. There are also motors that are safe to 80k in that size and I am just trying to find out whether the Neu 1527 2300kV competition also are.

    Actually this is related to the decision of buying a used boat having these motors in it.
    I just try to find out whether it is cool for me that these motors are in the boat or whether it just makes the whole thing expensive.

    Best Regards, Eike

  4. #4
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    As I recall, Neu lists the Kv as “partly” loaded around 30 amps, but not what Lehner uses - whatever that is. Expect up to a 20% drop in loaded rpm versus calculated when pulling above 300 amps. Heck, you can load the motor to 600 amps and see a 40% drop, go for it.

    The motor is “safe up to more than 60,000 rpm” only if the bearings are in perfect shape, and if the magnet wraps hold.....



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  5. #5
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    Don't believe the marketing BS about max speeds. Realistically the Neu 1527 motors are reliable and safe up to 45kRPM loaded. That leaves 15kRPM margin if the prop becomes unloaded. 60kRPM is not a good continuous point to target. Yes some guys have run these to higher speeds and in particular car guys use them at really high speed levels, but accept a ton of risk in doing so. These really high RPM values are for marketing purposes for the guys running GPS speeds on streets.

    As Fluid mentioned bearings, rotor wrapping and a balanced coupler will affect the lifetime at high speeds.

    The 1527 1D running on 6S is a SAW only type set-up, but it is a reasonable reliable one if you prop correctly. You can expect somewhere between 40-50kRPM loaded depending on the batteries, controller and prop. It will need a stout controller!

    Neu likely uses carbon over Kevlar for the rotor wrapping or adds more wrap material and does a better job precision balancing. I have not looked inside any of the later model Neu motors in 5 years, but their quality took a dip from their early motors.
    Tyler Garrard
    NAMBA 639/IMPBA 20525
    T-Hydro @ 142.94mph former WR

  6. #6
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    Don't props generally loose efficiency above 39K RPM?
    If this is the case, doesn't it make sense to target less than 39K RPM, and keep propping up to thermal / stability limits?
    Cheetah, Super Rio, (Mod) Starship (Mod and sold),

  7. #7
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    Quote Originally Posted by Fluid View Post
    As I recall, Neu lists the Kv as ?partly? loaded around 30 amps, but not what Lehner uses - whatever that is.
    ...
    The motor is ?safe up to more than 60,000 rpm? only if the bearings are in perfect shape, and if the magnet wraps hold.....
    Lehner gives the kV at best efficiency - actually this is also partial load but it also changes from motor to motor.

    I did a test with a Lehner SAW-setup last year:

    Actually this is calculated based on an unilog measurement and has to be interpreted right ;-)

    Not loaded the motor has a little more then 110% kv measured vs. nominal listing.
    When the boat has accelerated the motor reaches the nominal kV and shows a "close to 100% match" under load with the potential to use a slightly bigger propeller. This setup was not pushed to the limit yet.
    About 15% gap between no load and reasonably loaded is quite constant to my experience on many motors of different types (all inrunners).

    Quote Originally Posted by RaceMechaniX View Post
    Don't believe the marketing BS about max speeds. Realistically the Neu 1527 motors are reliable and safe up to 45kRPM loaded. That leaves 15kRPM margin if the prop becomes unloaded. 60kRPM is not a good continuous point to target. Yes some guys have run these to higher speeds and in particular car guys use them at really high speed levels, but accept a ton of risk in doing so. These really high RPM values are for marketing purposes for the guys running GPS speeds on streets.

    As Fluid mentioned bearings, rotor wrapping and a balanced coupler will affect the lifetime at high speeds.

    The 1527 1D running on 6S is a SAW only type set-up, but it is a reasonable reliable one if you prop correctly. You can expect somewhere between 40-50kRPM loaded depending on the batteries, controller and prop. It will need a stout controller!

    Neu likely uses carbon over Kevlar for the rotor wrapping or adds more wrap material and does a better job precision balancing. I have not looked inside any of the later model Neu motors in 5 years, but their quality took a dip from their early motors.
    Hi Tyler,
    thank you for the answer that I kind of expected but actually I was not sure.
    It is about details in the language and most people use Lehner for these purposes here in Germany so there is little knowledge on Neumotors here.

    On the other hand I wrote a few mails with Neu and the reply was quick, competent and friendly

    60k is the official and safe limit - it can be considered to be a conservative limit but it is the limit for the warranty.

    On the other hand expecting warranty on a SAW setup sounds strange to me anyway

    For example the communication of values is more direct at TP. For CM-versions they name the peak-values for 10sec including max. speed, not just current and directly tell there is no warranty on these motors. Whether the TP4050CM really last 80k or not is a different topic ;-) but the rating is that high that also 90% of it is enough when checking the unloaded szenario

    I am definately aware that a bursting rotor can cost the whole boat, there are enough people that tried that out. The rotor kills the winding, causes a short circuit and the party is on...
    This is exactly why I ask.

    Quote Originally Posted by RaceMechaniX View Post
    ...
    The 1527 1D running on 6S is a SAW only type set-up, but it is a reasonable reliable one if you prop correctly. ...
    I think this is a good summary. Thank you!

    Quote Originally Posted by larryrose11 View Post
    Don't props generally loose efficiency above 39K RPM?
    If this is the case, doesn't it make sense to target less than 39K RPM, and keep propping up to thermal / stability limits?
    This depends very much on the propellers that you use.
    When setting up my last years boat - the red one from the youtube link I tried with less cells and then increased the number of cells, measured speeds, rpm, currents, ... all that stuff.

    Propellers optimized for high rpm don't work well at too low rpm. I did not have any efficiency issues up to 50k under load but I did not use the propellers from my Tug

    On the other hand you put so much power into a SAW setup - maybe you loose a little bit of efficiency but if that enables you to keep control it also helps. Torque and lift from bigger propellers are probably more difficult to handle...

    Thanks a lot!
    Best Regards, Eike

  8. #8
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    http://www.offshoreelectrics.com/neu-motor-chart.htm

    Look at this chart from NEU;

    Larry
    Past NAMBA- P Mono -1 Mile Race Record holder
    Past NAMBA- P Sport -1 Mile Race Record holder
    Bump & Grind Racing Props -We Like Em Smooth & Wet

  9. #9
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    Hi Larry,
    I did but it does not make a difference between competition versions and the normal ones.
    Eike

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