First run with my 6s rigger and NEU 1527

[StevenBryant]

hey Guys

i ran my 6s rigger today to test a NEU1527 1.5D which i purchased from someone on OSE. The first run was with a stock 1455 and was only on the water for 30 to 40 seconds, the boat was slower than i expected so i changed the prop to a 1457 and something very strange happened on the first lap, as i came around buoy 1 the RPM went up and the boat slowed to a stop. Initialy i thought i had snapped a flexi so i went and recovered the boat, only to find out the flexi was intack, the dog drive was still set, the collet seemed to be done up tight, motor was luke warm. After retightning the collet and checking the flexi i gave the boat another run with the same results, however this time rather than recovering it i gave it 10 seconds then throttled it up and all was good for about half a lap then the same problem happened again, so i gave up.

After getting home i checked the data from the datalogger on my MGM 28026 esc and found some very strange data on the rpm and peak current. The RPM should have been around 28K loaded on 6s, however when the slippage occured the RPM was jumping up to 46K and the peak current 915amps...

Datalog.jpg

A friend recons that the magnets might have be slipping on the axel (8mm)....

I decided to hook the cells back up and throttle the motor up and down and check the data, the data came out as expected for a 1500kv on 6s @ 3.7vper cell. However as i throttled up i small spark came out of the end bell hmmmm....

If anyone could help me i would be much appreciated

[StevenBryant]

data log.JPG

[photohoward1]

I'm going to guess the windings shorted out. Just a guess?

[ray schrauwen]

I think something similar happened with my TP4070-1250kv motor. My motor gets very hot compared to yours.

I ran it on 6s in a Whip 40. When I tried a new motor (other brand same dimensions 80kv less) the problem went away.

I'm surprised to see a Neu do this.

[Fluid]

Any used motor, Neu or other, has the risk of damage. The previous owner could have I over-heated it, bent the wires excessively, over-revved it....or it just had a thin spot on the winding coating. .

[StevenBryant]

I do understand the problem with buying second hand motors fluid, this particular motor had only been used 5 times and is from a very reputable source which is why i purchased it........

Is it possible for the magnets to slip on the axel?

[StevenBryant]

Video of the first run when the motor slipped.

https://youtu.be/0LlMMaB7pSo

[Brushless55]

I would send it back to NEU and see what needs replaced ..

[Fluid]

I do understand the problem with buying second hand motors fluid.......Is it possible for the magnets to slip on the axel?

It is possible, but the friction would heat the shaft to a very high temp very fast. The right thing to do is to send it to Neu for repair, as suggested above.

Even reputable sellers can have problems...I assume that if there was a problem with the motor the seller was not aware of it. I have had relatively new motors fail for no reason, it happens. Over the past ten years I have purchased quite a few motors used with a high success rate, a good way to save some $$$.


.

[NativePaul]

It is possible for a rotor to slip on a shaft, I have never had it happen to myself but I have heard of it happening several times.

What collets do you use? I bought 2 used Neu motors last year (both work fine) and both had circular discoloured scorch marks on the shafts, and no flat spots, I assume that the previous owner used MPB style double collet couplers rather than grub screw types I use, and had them spin on the shafts. If a collet slipped it could account for the sudden increase in RPM as the motor unloaded, and Neus are carbon wrapped so if some of that wrapping were to come off at high RPM it could account for sparks and high current as it wears through the windings and causes shorts. Neu have a good reputation for service so although it will be well worth the few quid it will cost to send it back.

I don't understand that datalog, does the manual say what the difference between input current, peak current, and pulse current are? I notice that input current, pulse current and input power are reasonably consistent throughout, but the peak current raises significantly in the highlighted area.

[crispyspa]

Had that happen on a Flux 1/8 scale Hpi Savage once....It's the magnet spinning on the shaft. I squeezed a bunch of thin CA in there after ordering a new motor. Haven't had the guts to try it out yet.

[RandyatBBY]

I bought the motor from a gent hear on OSE I bench tested the motor it was good on my end. I never ran it. I only sold the motor to pay bills no other reason. I can not read the graft it is too small. When ever I run a boat I own what I do to it and its parts. I do not know much about the set up either to state a opinion. It was a good motor when I had it and was going to use it in SAW racing.

[StevenBryant]

If you have a look at the second post Randy you will be able to read the graph....

I have checked the seating of the dog drive on the stub shaft, the seating of the collet (Aeromarine twin grub screw), and the flexi cable for signs of slippage. All are solid and nothing will move which leads me to belive that the magnets must have slipped on the axel.

On a bench test using onboard datalogging on my MGM esc and extenal AMP and RPM sensors the motor seems to be running fine, i have only had the one occasion when a spark came out of the bell end.
below is typical of the readings, RPM and input seem fine but the PEak is abit high :)
At 100% throttle
RPM 36,900 ~
Input Current 20Amp
Peak Current 300Amps

I took the water jacket off to get it ready for sending to NEU, and well i was quite shocked at the amount of salt residue on the water jacket, the original owner had obviously used the motor in salt water and had never cleaned it out. The salt has eaten away at the Anodizing and had corroded the can quite alot certainly does not look pretty...........

Well i'm going to email NEU motors and see what its going to cost, with shipping from the UK to the US and back again along with the repair cost i think i might just put it down to experience, dam shame as this was the first NEU motor.

[kfxguy]

Check the wires coming out of the end cap. See if there's any bare spots. Also see if one of the wires is loose

[StevenBryant]

Already checked the wires they are solid and still covered in silicone insulation.


Sent from my iPhone using Tapatalk