1700kv sensored Taurus Rocket motor(-cables) hot (no load)

[Jay81]

Hey,

I hooked a new Taurus Rocket 1700kv sensored motor up to the SkyRc Ts150competition ESC to run in my Big Rock and have some problems.

- After like 10 seconds of half throttle cables are really hot, motor starts getting hot.
- Also one weird thing; with sensor cable connected it will rev much higher then without.

I am not sure if I forgot a shim on one side of the motor when I took a look inside, solder joints seem to be okay, and I run the exact same combo in my Kraton without any heat whatsoever.
However I did notice two things while disassembling:
- Strator /windings has one spot where I'm not sure if that could cause a short of some kind (pic)
- Rotor is a bit scratched up from some burr that was inside - should be all clean now.
I use 4mm plugs, once I connected ESC wrong and some sparks flew, one of the connectors is kind of dull ever since.
So, the motor runs, but gets super hot super fast & revs much higher with sensor cable plugged in.
Also, it sounds a bit as if it's running under water (never seen water).

Anyone has an idea what could be wrong? Could the 4mm plugs be too small? Motor draws 95amps...

Any help would be greatly appreciated!

 

[Turbobrick]

If there is a short on the windings.
This will cause increased capacitance and power factor as well as reduced insulation resistivity. ... of the entire machine winding kV = the rated machine terminal potential (rms kV)

Ideally you need to do an insulation test on the motor and check for leakage.

 

[Jay81]

Thx Turborick, by now I did test the motor thoroughly, I did the following:

- Spun Motor on drill (1300RPM) for 5 minutes straight, no dissipation, no blocking, no strange noises that I can tell (drill sounds kinda weird)
- Tested all 3 phases with multi meter, looks alright.
- Checked for short circuits between the stator and the windings - none.
- Hooked up the wires to a multi meter while spinning on the drill, I was NOT able to get any current out of it (I might use the meter wrong in that instance, I have to look deeper into that).

Motor still runs, gets hot, revs higher with sensor cable and starts to get on my nerves. Might just get a new one, if this turns out to be more of a time-eater.

Anyone else has an idea? The ESC is brand new too, I plastic-dipped it, but that couldn't have hurt it I suppose.
Could it be that one - possibly - missing shim?

 

[LibertyMKiii]

4mm bullets shouldn't be an issue. I ran over 300 amps through the Arrma motor with factory 4mm bullets.

If you wanted to buy one of these motor testers it would reveal possible issues with resistance and amps to turn no load. One of my new favorite tools to ensure I have an efficient motor in my high speed cars.

This is a good TP 4070 with the 2080KV winding. Notice it pulls 3.6A with no load.

This is not necessarily a "bad" motor but it would surely run hot and eat up batteries in a hurry.
Same specs, it is 4070 motor with 2080KV rating. Doing the same test it pulls 6.5 Amps. I fully charged the battery to 8.4V and the same results of 6.5 Amps. Slightly higher wattage consumption in that scenario but still proved this motor was a power hog. TP Power never agreed with me though...

 

[Jay81]

That surely is a neat tool - it will cost me exactly the same as a new motor though...

I have heard good things about the Rocket motors, so I'm willing to assume their rating concerning power draw is halfway decent.
If this motor proves to be unsavable, I might get the 1400kv version. 78A and <36V for 71€, if just there wasn't the waiting for shipping from Gina...