Fried Servos

[elderfo]

I just received an order yesterday and didn't get to start messing around with it til this morning. Out of the 4 servos (TowerPro SG-5010) I received, only 2 of them work at this point. One seems to be completely seized up and the other one can be turned by hand (albeit with some force), but only rotates about 10-15% of it's range in one direction when powered/connected.

I have them connected to my raspberry pi via the AdaFruit Servo Driver (and power supply). I was tested one at a time on channel 15 using the Servo_Example.py script. The first one was run for maybe 2-3 minutes total with various tweaks to the script. It eventually completely seized up. The second one, operated a little longer then stopped responding after moving the initial 10-15%. In both cases, the bottom of the servo was extremely hot to the touch.

I have run the other two servos continuously for longer than either of those servos.

Does anyone know what could have caused this? Like i said, i was tweaking the settings in the script a bit on the first one (frequency, servoMin and servoMax) to see what they did, but i did not think they would fry the servos.

With the TowerPro SG-5010, are there suggested ranges for the frequency, servoMin and servoMax?

[elderfo]

I just realized this should've probably been posted in the "Other Accessories" forum as it's likely unrelated to my raspi which is operating as expected

[adafruit_support_bill]

Hi. I moved the topic for you.

In your initial tests, were the servos moving freely? The servoMin and servoMax in the example code should be appropriate for the TowerPro servos. As analog devices, there will be slight variations from sample to sample, but most servos work well with those limits. If you set those limits too wide, the servo will hit the internal physical stops. Hitting the stop hard can damage the geartrain. Pushing against the stop continuously can cause the motor to overheat.

[elderfo]

Thanks for moving the topic!

Both servos were moving freely on my initial tests. With the completely seized servo, i did notice it was humming (probably up against a stop) but when i noticed that, I immediately unplugged it. I don't believe the gear train has been damaged on either, but I cannot confirm without taking them apart.

[adafruit_support_bill]

Alright. Sounds like these two packed up on their own. Contact support@adafruit.com with a link to this thread and they can replace them.

[elderfo]

Just curious, are these servos known to be volatile or did i just get some bad apples?

[adafruit_support_bill]

These are 'budget' servos. As it says in the product description:

They aren't the highest quality servo (which is why they are less expensive) and so are not suggested for hobby planes.

They are not as smooth, quiet or reliable as a high-quality servo such as a Futaba or HiTec. That said, we don't get many returns on these. I think you just hit the jackpot.