120HV - Ground Strap to motor

[GnarfleTGarthok]

After working with the timing I still have a hot esc unless I move the timing very low. I'm not sure where the built in thermal protection will cause the esc to start to shut down or what the maximum temp of the HW 120a HV is but it's running around 150F at 12khz and 15 degrees and it certainly has that hot electronics smell when its back on the ground.

After a lot of research and help from fellow freaks in the 7HV group, running the scorpion 4035-560 at low timing is a horrible idea as it can generate magic smoke quickly.

Which leads me to the question about "grounding" for lack of a better word. I currently have my ESC bolted to the carbon frame. This is the first time I haven't used velcro and a strap etc. The ohms are very low to the motor but it still has some resistance.

So for the point. Should the ESC be left floating (the case not touching the frame) or should I run a wire from the case of the ESC to the motor? And any help on what the shutdown temp of the ESC is would also be helpful. I can't find that information anywhere. So I don't know if 150F is well within spec, near it, or too hi.

Thanks

[P.I.Engineer]

check all your solder joints

[GnarfleTGarthok]

The solder joints are basically perfect. I just ran an ohm check on all of them and no resistance in any of them.

[chucky21022002]

On a sunny day I flew my 7hv on throttle curve mode because i forgot to put a common ground on the esc when I change my BEC to a flightpack. The max temp I got was 78F at 100% throttle. The location of the esc is completely covered so I decided to install a brushless fan on top of the heatsink which I bough it from a computer shop.

[GnarfleTGarthok]

OK I finally had a chance to run a few tests. I just posted this in the 7Hv section but figured I should follow up here also. The timing is set to 12Khz for all timing tests.

Each flight was done from a hover just doing pitch pumps to 10 feet and back to 3 feet for 5 minutes. Then recording the temp as fast as I could get the canopy off after landing. The temperature starts climbing after it's off since the motor doesn't have the fan running on it. So overall these values are close. The ambient air temp outside is 89 degrees.

7.5 degrees Motor 170 ESC 164F
11.25 degrees Motor 170F ESC 163F
15 degrees Motor 150F ESC 143F
18.75 degrees Motor 141F ESC 129F

I stopped at 18.75 as its performance with the governor turned on is incredible. No weird under speed or over speed issues at 18.75 compared to the other values with the scorpion motor. I also just sounds better at this value. Like it's not laboring. Hard to explain but I'm sticking with 18.75 until I get a few flights for real on it.

Thanks for the help.

Chucky what voltage does the fan run at?

[chucky21022002]

Originally Posted by tokenlefty

OK I finally had a chance to run a few tests. I just posted this in the 7Hv section but figured I should follow up here also. The timing is set to 12Khz for all timing tests.

Each flight was done from a hover just doing pitch pumps to 10 feet and back to 3 feet for 5 minutes. Then recording the temp as fast as I could get the canopy off after landing. The temperature starts climbing after it's off since the motor doesn't have the fan running on it. So overall these values are close. The ambient air temp outside is 89 degrees.

7.5 degrees Motor 170 ESC 164F
11.25 degrees Motor 170F ESC 163F
15 degrees Motor 150F ESC 143F
18.75 degrees Motor 141F ESC 129F

I stopped at 18.75 as its performance with the governor turned on is incredible. No weird under speed or over speed issues at 18.75 compared to the other values with the scorpion motor. I also just sounds better at this value. Like it's not laboring. Hard to explain but I'm sticking with 18.75 until I get a few flights for real on it.

Thanks for the help.

Chucky what voltage does the fan run at?

Hi, it is 12v. Since Im running a flightpack 2s which is 7.4v and regulated to 5.5v I soldered a booster regulator to make it 12v. Brushless fan is so quite and running at 5000rpm so the esc is nice and cool now. I'll upload some pics later.

[chucky21022002]

Heres the pics as promised...

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[GnarfleTGarthok]

Excellent Mod Chucky. It's interesting that Hobbywing has fans on the Car ESC's since they don't get much airflow. I wonder if we could convince them to have the option for a Heli setup when under the canopy. It would be easy enough for them to implement. They did a good job on the anti-spark connector and the extra capacitor pack.

[GnarfleTGarthok]

Just a quick update now that I have a dozen flights on the 7HV. The HW 120HV internal governor is so inconsistent that I have completely given up on it. It needs a major software upgrade but as the performance of the gate circuits degrade with temperature changes it becomes much worse. I'm flying throttle curves now and it works well. I see why the V-bar guys like these with the vbar governor. But I wouldn't recommend the HW internal governor at this point until they make some major changes to it.

[GnarfleTGarthok]

Chucky, where did you get the boosted regulator for the fan?

[chucky21022002]

Originally Posted by tokenlefty

Chucky, where did you get the boosted regulator for the fan?

I bought it from here http://www.fast-lad.co.uk/store/33-9...0-p-17599.html

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