Hello all, I’m stuck and really need help.
I’m trying to determine the servo speed of my continuous rotation HS755MG servo. Normally this servo isn’t CR but it was modified to be by ‘Servo City’. Not sure all what they do to it.
The standard specs of the HS-755MG are :
6V 0.23sec/60°
That gives 82.8 RPM w/ no load
When I use the stopwatch on my phone to calculate roughly 10 rotations I get 13.3 sec’s everytime I do it and I’ve done it over a dozen times trying to average these results. That gives ~80RPM. Seems about accurate, right?
I wanted to double check the results and I bought a photo tachometer. It gave consistent readings of 45RPM’s. I didn’t rust that tachometer and returned it. Bought a much higher end tachometer and it gave me the same 45RPM readings. Tried the photo tach inside, outside, different servo horns, etc.
So now i’m doubting myself. Is the servo horn spinning at 45rpm or closer to 80rpm? And how can I figure this out!?!
Thanks
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To clarify: I’m moving the servo right now with a servo city 2-axis Manual Joystick at 6V with no load and I like the RPM rotation I’m getting, however I need to know what that rotation actually is before going further with R&D. I have to make sure definitively that I know what that RPM is.
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@Overkill Welcome to the RobotShop Community. Did you just count the number of revolutions in 10 seconds and multiply by 60 to get RPM? You could take literally only a minute and count the evolutions to verify (no calculations required at all)?
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No I never counted how many total RPM’s in 60 seconds lol I thought it would be too imprecise. Just did it now and low and behold I get about 45 revolutions in 60 seconds. So I guess that does backup the tachometer speed. Well I love it when the answers are this simple lol. Thanks for the help.
Luckily it can be done this way. I guess it would be really difficult to determine if it was say something like a few hundred or thousand rpm. Something you couldn’t count by hand. I guess you have to make sure your tachometer is calibrated and that it is the only tool you can trust in the end?
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