Seaking 180 ESC RPM Question?

[Howard]

I was wondering if anyone has experienced this before. I had a 60 amp esc in my boat running 3S lipos. My dry RPM using my tach at WOT was about 35,000 RPM. Now that I have the 180 seaking installed it runs about 45,000 RPMs with only 2S lipos. Yes it screams at wide open throttle. The throttle works fine. Em I crazy or what???? I have not tested in the water yet.


Howard

[Howard]

PS, I'm using a 2600KV motor. Is it possible the motor is bad? I smoked the 60amp esc. Thus the new 180 esc.

[Fluid]

First off, never run a BL motor at full throttle without a load - nothing good will happen if you do. The rpm you see is pretty meaningless, what matters is rpm on the water. So don't be crazy :nono: test WOT in the water only!



.

[detox]

Tach is probably wrong using 2s

[Boaterguy]

unless the 3S is wimping out at WOT, probably not but you never know.
specs on the batts?

[drwayne]

3S (12.6) 2600kv ~33krpm ..... so 35k is about it for a foolish wot on dry land with inaccuracies of tachs
2S (8.4) 2600kv ~21krpm ~! 45krpm not possible... was tach configured wrong ?..

What tach ?
aero blade counting tachs just tell lies on small diam props with large blades for eg.
W

What type of tach.. a prop blade counter ? Was it set to count one blade..

[Boaterguy]

21.8k is what you should be getting (approx)
that's about half of what your tach is giving so I think dr wayne hit it on the head.

[Howard]

Globee intellitach definitely set on 2 blades. I've done this many times before with no adverse affects on the boat/motor. Of course I don't run it long maybe 20 to 30 seconds tops. I can tell just by the sound that the motor is screaming. It's really wierd and it makes no sense I know but I guess I'll have to see what it does in the water. Batteries are 2S 5000 mah 40c.


Howard

[Howard]

prop is a balanced, polished octura x435. Like I said it makes no sense I know but this is what it is doing

[drwayne]

what brand motor here ?
2 pole or 4 ?

20-30 seconds is a nightmare long time wot unloaded.
It's the unsensored wot and the unharnessed wind down to idle that's bad.. all that backemf with nowhere to go...very bad for esc/motor... is that what caused your stock 60A to go
:flashfire:

If you like your electronics. dont repeat that


lightbulb moment
you run 2S2P and have them wired wrong = 4S1P @2600 = 43krpm ??

[Howard]

Great Planes Ammo 36-56-2600 In-Runner Brushless Motor No the first esc went while on the water running 4s 4000 40c bat. Nothing is wired wrong, I've been doing this for years and this is the first time this is happening :doh: I'll run this in the water today and see what happens

[drwayne]

Great motor.
Ive it's bigger sister in a 6ft aero

Eagle tree make a good rpm counter applet for under 100 complete .. leave onboard and grab loaded rpm.. good for prop choises too.

Not common, nor impossible, for an esc to misread pole positions in can at high rpm and misfire... prompting rotor lock or rotor flash ( spins higher )

best of luck !

W

[Howard]

OK Doctor, I know you think I'm nuts (that's OK :olleyes:) but for your diagnosis I made a video. Hope you can help...


I'm only using 2S 5000 40c ...everything is wired correctly. As I mentioned the motor is screaming. Although I did this for a very short time it is definitely hitting the 50,000 rpm range without a doubt.


http://www.youtube.com/watch?v=8t7s_bsldJQ

[drwayne]

mark the trailing edge of your prop blades with a solid black line and try again.
W

[drwayne]

if the motor is a 2pole, and those esc fire for a 4 pole, the motor will rev twice as fast as kv suggests.

Dont know the time where you are, but its 11pm here Sat night, and Im to work at 0600 Sunday.
time for me to Zzzzzzzzzzzzz.

will log on in 18hrs
W

[Howard]

hmmmm maybe that's it Doc, I tried the black line you mentioned with the same results. It's 7:30 am here.

I also have the same setup in a REd Evo that I have and with 3S it runs at 30,000 rpm and with 4S it runs at 40,000 RPM's which is normal. So if you are correct about the 2 pole and 4 pole how do I fix it? Or is there no fix?

Howard

[Howard]

OK Doc have a peaceful sleep :-)

I just did some research and discovered the Ammo motors are 2-pole. So maybe your on to something.

So I'm wondering my options now. 1) will I fry the motor running it this way? Should I lower the timing on the ESC maybe?

Or just use a different motor with this ESC?

Thanks for your help, I think were pin pointing this problem

[drwayne]

The catch22 here ( the twist ) is that if the 2 pole is actually driven twice compared a 4.giving us 2S@2600kv=45krpm, then why does 3s@2600kv act like a 4pole with 35krpm ?
Ive not taken a T180 apart to learn scripts or limits, I design things, not copy them.!
I recall reading something about 60k rpm firing speed limit
However, not all esc work for all motors.
Grab a diff esc.. swordfish/aquastar/hifei120A will fit this bill..


Id guess Jay is lurking about somewhere.
comments ?

W

[Howard]

Well Doc I did try a different ESC today ( I guess we think alike) and had the same results. I then put the boat in the water and it ran OK until I gave it full throttle. It ran for about 15 seconds and then started to slow down drastically. I brought it in and the motor was smoking at 155 F. Conclusion... The motor was/is bad. It's funny because I had a similar problem awhile back with a used boat I bought and didn't think about it until today. The motor also screamed and got real hot on land. I never used the motor and just figured it was bad. Now that I think back and with this incident my conclusion is if the motor screams like these did there's something wrong internally as apposed to a motor that is just dead and doesn't run.


Howard

[drwayne]

722am
glad you have it sorted.
B)