FS90R Continuous Rotation Servo fails

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DaveKay
 
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FS90R Continuous Rotation Servo fails

Post by DaveKay »

Invoice # 812405
ordered June 18, 2015

The servo, which initially worked, has gradually developed an intermittent failure to turn the gear set. The motor runs, but the gears do not move. If I "assist" it by hand it will sometimes unstick for a while.

This may be a problem with this model. I had previously purchased the same motor from another source, and it failed the same way, eventually never turning the gear set..

Running off the 5v output of an Arduino Micro, which is in turn supplied by a 9v battery.

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Re: FS90R Continuous Rotation Servo fails

Post by adafruit_support_bill »

Does the problem persist if you run the Micro powered via USB?

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DaveKay
 
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Re: FS90R Continuous Rotation Servo fails

Post by DaveKay »

Yes.

I run it for a few turns in each direction (+/- 30 degrees from 90), with pauses. Code below:

Code: Select all

#include <Servo.h> 
 
Servo myservo;  // create servo object to control a servo 
                // twelve servo objects can be created on most boards
 
int pos = 0;    // variable to store the servo position 
 
void setup() 
{ 
  myservo.attach(9);  // attaches the servo on pin 9 to the servo object 
} 
 
void loop() 
{ 
    myservo.write(90);               
    delay(2000);    
    myservo.write(120); //ccw
    delay(2000);    
     myservo.write(90);               
    delay(2000);                
    myservo.write(60); //cw
    delay(2000);
     myservo.write(90);               
    delay(2000); 
  }
Last edited by Franklin97355 on Thu Jul 23, 2015 5:14 pm, edited 1 time in total.
Reason: Added [code] tags

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adafruit_support_bill
 
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Re: FS90R Continuous Rotation Servo fails

Post by adafruit_support_bill »

So the motor is spinning, but the output shaft does not move? What do you have the servo shaft connected to?

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DaveKay
 
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Re: FS90R Continuous Rotation Servo fails

Post by DaveKay »

There is nothing on the servo shaft.
The (apparently) brass gear on the motor shaft is not driving the nylon gear set at all.
My guess is that there is too much play in the gear that meshes with it.

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Re: FS90R Continuous Rotation Servo fails

Post by adafruit_support_bill »

If you contact [email protected] with a link to this thread we can send a replacement.

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DaveKay
 
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Re: FS90R Continuous Rotation Servo fails

Post by DaveKay »

Great. Thanks for your help!

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DaveKay
 
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Re: FS90R Continuous Rotation Servo fails

Post by DaveKay »

Thank you for the replacement unit. Unfortunately, it has failed in the same way.

Speculating as to cause: While there is no load in the current setup, it is possible that the motors were briefly (<2s) stalled during mechanical tests when the shaft was out of alignment.

I would not think that a stall should cause a gear train failure, however. Is it your experience that stalls damage micro servo motors?

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Re: FS90R Continuous Rotation Servo fails

Post by adafruit_support_bill »

Unfortunately, yes. The gear trains on the micro servos are pretty delicate - even on some of the expensive, premium brands. I've stripped more than a few myself.

The metal gear models are more robust. But I don't know of any continuous rotation metal gear micros offhand.

If you contact [email protected] we can issue a refund for the servo.

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DaveKay
 
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Re: FS90R Continuous Rotation Servo fails

Post by DaveKay »

Thanks for the help.

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