ICE 50 Governer Readings based on 90% eff

[solidhelix]

Been doing some testing on the governor of the ICE 50. It seems when you put in the gear ratio, KV and Poles, it fails to allow you to enter the motor's efficiency and assumes from my calculations that the efficiency is 90%.

Scorpion lists my motor (HK-2221-8) as having a 92% efficiency.

Therefore If I enter a governor speed of say 2800 rpm in CC software, I'll really be getting around 2862 rpm.For 3200 rpm, around 3270.

Not that this is a big deal or anything, It would be nice to see a place to enter the efficiency into the software.

Since it seems to be calculating the rpm which is shown in the graph from the electrical rpm in volts and KV value entered, What you are reading in the graph isn't correct but can be corrected if you could enter the efficiency of your motor.

You might say that the efficiency varies, but I've been reading peoples posted headspeed for my motor and gear ratio and found they are consistent with a 92% efficiency. and CC is clearly assuming a 90% efficiency.

I've found a workaround by lowering the entered KV value in the software until the numbers matched. but an only get to an accuracy of 1 rpm between 3 headspeeds 200rpm apart.

By changing the KV value in the software won't do anything other than change reported rpm in the logs, but it may be a lot closer to actual.

If I'm out to lunch, let me know

[JoeW]

I think you're over-doing it...

The ESC knows quite reliably where the motor is (once it's turning) otherwise it would never be able to get the timing right to pull it around a full revolution.

The software assumes in your gov setup, that it needs to reserve a certain amount of headroom so it can keep constant when you start bogging it, and a certain factor of efficiency. Lets say it keeps a generic 10% in reserve for efficiency, then a few points for headroom.

The precision in that measurement though, is going to be in the motor RPM, then multiply the error rate by a factor of your gear ratio. So I'd say your precision is going to be -/+ (x) * gear ratio.

The number I put in my gov setup, is (within reasonable error rates) the same number I'm getting out of my telemetry RPM sensor, which is (within reasonable error rates) the same number I'm getting from an optical tach.

Good enough that I don't bother with the Telemetry sensor or the Tach any more....

[solidhelix]

Originally Posted by JoeW

I think you're over-doing it...

The ESC knows quite reliably where the motor is (once it's turning) otherwise it would never be able to get the timing right to pull it around a full revolution.

The software assumes in your gov setup, that it needs to reserve a certain amount of headroom so it can keep constant when you start bogging it, and a certain factor of efficiency. Lets say it keeps a generic 10% in reserve for efficiency, then a few points for headroom.

The precision in that measurement though, is going to be in the motor RPM, then multiply the error rate by a factor of your gear ratio. So I'd say your precision is going to be -/+ (x) * gear ratio.

The thing I noticed is that when I work out the theoretical rpm of my setup, I use 92% efficiency. When you enter the headspeed into the software you can click "info" and it will tell you the % of power it's using. 95% is max before you're in the red. Those percentages it displays for those head speeds are consistent with a 90% efficiency in a standard headspeed calc. If my motor is 92% efficient, there from what I can tell will be a discrepancy. I know it isn't a big deal or anything, just trying to figure it out. And I'm still searching for an acurate Tac to further test.