Motor Balancing Question

[jumanoc]

Here is how to I did using my phone with Vibrometer App.
https://www.youtube.com/results?search_query=balancing+motor+with+a+vibrometer

Can you give me the details of how you powered each motor independently? Is it as easy as simply unplugging the other three and then powering up the radio and Phantom?

Thanks

Gary

You said it. Unplug 3 motors and start CSC without props. Put a piece of tape (ie 15 mm on motor can) and retest. Move 5 mm the tape and retest .... repeat until lowest vibration is found. I done 2 times with my original motors and then with T-motors. Don't worry about a annoying beep - beep coming from ESCs when disconnected and you start your test motor.

 

[jumanoc]

I'm not at home so can't check - but I seem to remember that it was possible in the assistant software to run each motor on its own to test the direction of rotation for example. Maybe I imagined it.

In Phantom 1.xx Naza Assistant you can test motor by motor individually, but it is only a start-stop test. That doesn't work for calibration because you require full motor run.
This video shows that useful tool after I did the balancing and detected a damage bearing:

[youtube]https://www.youtube.com/watch?v=IdkJ7BbEDsE[/youtube]

 

[jarance]

Get a ESC tester from China (AliExpress). They are relative cheap and It work much better and you can replicate the speed.

Is the ESC tester a "Plug 'n Play" proposition? Just unplug the ESC from the Phantom main board and plug it into the tester? I assume the knob controls RPM?

Gary

yes the ESC tester is a digital tester with numerical display. It has 4 outputs that you can hook up to four motors or just one motor.
The output from the tester is either PWM output or voltage output.
PWM can be used for ESC control and Voltage can be used for servo control.

I am not sure whether I am allow to post external link (please remove if not allow) but here is the link to the ESC tester for more detail.
http://www.aliexpress.com/item/HJ-1...ster-for-RC-Helicopter-Servo/32215924787.html

It used to sell at USD7.60 but the price have increase to USD8.00.

 

[phalcon51]

Can the display show motor rpm, or can it be inferred from whatever it does display?

Thanks

 

[phalcon51]

Seems like a lot of effort that is probably unnecessary.
Is there any reason to suspect that the motors might be unbalanced?

Sure, it's a mass produced item with each machined part of the item made to certain tolerances. If a few of these machined areas are produced at the extremes, or possibly even beyond these tolerances you can end up with an unbalanced motor. If quality control is particularly good then a batch of motors will probably run quite smooth. But if it's a Friday afternoon and the quality control guy (or gal) is in a hurry to meet their friends at the local watering hole (or whatever other vices they might have in China) or a Monday morning and the QC folks are still a little hungover, then the product may by sub-par. I liken it to blueprinting an engine, where you make sure all the pistons weigh exactly the same, not + or - several grams and the bearing clearances, valve timing, ring end-gap, etc. are all spot on. Then you know everything is as right as it can be. Plus, I like to tinker with stuff. It keeps me from getting bored.

Gary

 

[jarance]

Can the display show motor rpm, or can it be inferred from whatever it does display?

Thanks

Unfortunately, the RPM of the motor is not display on the LED display. You will need a tacho meter for that.

But the ESC being digital, the PWM output is always consistent and hence the speed of the motor is directly dependent on the setting of the PWM.

For dynamic balancing, you need to have phase angle as well as the amplitude to accurately determine the amount of weight and the sector to add the final weight.

If phase angle is not available, then it is a matter of trial and error but you need to have the same speed to determine the result.

 

[phalcon51]

Thanks, I appreciate the feedback.

Gary