BLX 185 ESC has motor Surging at WOT .... Not with BLX motor tho ??? Any ideas

[Big Kid]

As stated BLX185 ESC .... With the stock BLX 4274 size 2050 kv everything runs great, smooth with absolutely no issues noted.

Now with a smaller 3542 size 2250 kv outrunner we have the issue. Have reset esc to factory default, played with what setting we can change and the same issue happens no matter what .... WHICH IS THIS
Watching the ESC light it go's RED as we throttle up and the motor starts up and runs fine, it continues to gain RPM with throttle increases ALL THE WAY to JUST SHY of WOT ( Still a Red light ) ... When the motors starts pulsing Up/Down in an even manor ... @ 1 second between high and dropped rpm back & forth ... Odd.
Then when throttle pegged to WOT and light go's GREEN telling ESC is at WOT the motor is singing at full RPM and NO SURGE noted.

So my thoughts are a frequency issue or mismatch of what the Motor wants differing from what the ESC is preset to ??
Being an OEM motor is a 4 pole in-runner and the Out-runner a 14 pole

Any idea here guys ?

 

[Chapinb]

I'd guess it's outside the range it's capable of. The blx might only work with 2 and 4 pole, 8 maybe. 16 and it throws a fit.

What on earth are you using a 4000w esc on a little outrunner for? A EDF?

 

[jkflow]

Yep, pole mismatch.

 

[Big Kid]

Thanks guys ...
little bit of fooling around perhaps found something ? tho not sure whats happening other than ESC might see the motor is maxed on voltage / rpm ? * Don't see how being non sensored ???

My 3542 is rated as a 4S maximum and am running it on 4S
For giggles plugged motor into my TYPHON which I run as a 3S rig and also uses the OEM BLX185 ESC ( Not motor tho ) Well I'll be damn it revs all the way threw power band without an issue to green light maximum ... No problem

Ok, plug in a 4S on the typhons BLX185 ESC ... SAME THING as other BLX185 ESC with the Hi/low surge just before green light WOT ... Seems the motor is getting maxed out and ESC is Giving a warning perhaps with the surge somethings Fubar ... Just no idea .. but seem to of found it ... sorta I guess

 

[Big Kid]

I'd guess it's outside the range it's capable of. The blx might only work with 2 and 4 pole, 8 maybe. 16 and it throws a fit.

What on earth are you using a 4000w esc on a little outrunner for? A EDF?

The Crawler converted Kraton ... Had the ESC and it's been working just fine ( Until going to 4S a few weeks ago ) and just now trying to figure out why the Weird surging.

 

[cancelthefuture]

Even outrunner specific ESCs like RhinoESC ask you to set the pole count in the configuration settings, your ESC isn't set up for this type of motor.

 

[Chapinb]

The esc assumes the rpm based on how quickly it changes poles. But if it's calculating with the assumption of 4 poles, the 16 pole motor will appear to the esc to rotate 4 times for every single revolution. Spinning 20k but the esc sees 80k.
It might be limiting because it can't change poles as fast as it's required, usually why esc have either pole or rpm limits.