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-   -   servo help (https://www.rcuniverse.com/forum/questions-answers-154/1079248-servo-help.html)

blindfly 08-22-2003 02:42 PM

servo help
 
hi,
I am recently bought a futaba s9252 (it's a digital), and using a 6v battery pack.
and well, on the back of it it says "use 4.8v only".
now, I know that basically all servos works at 6v.
on the futaba site it says "not recommended".
Has anyone ever used this servo w/ 6v pack, or has any idea whether it works well?

FLYBOY 08-22-2003 02:45 PM

servo help
 
Seems to me, if the company doesn't suggest using 6 V with that particular servo, you should stick to 4.8. Sure someone on here might tell you it will work, but for how long? If futaba says stay with 4.8 on it, maybe if you run 6V you will burn it up in short order. Why push it.

bsindel 08-22-2003 03:39 PM

servo help
 
You could insert a couple of silicon diodes connected in series into the power lead going to the servo and that would drop the voltage at the servo to 4.8 volts.

Bill

3DFanatic 08-22-2003 08:15 PM

servo help
 
KISS (Keep It Simple Stupid)

Go with flyboy's advice and run the 4.8.

john flynn 08-23-2003 12:38 AM

servo help
 
Gidday again Bill, please disregard 3dmagic's rude reply to your advice. He has obviously put his mouth into gear before thinking it through. If Mazlat's other servos are running on 6 volts then why not throw in the diodes on the futubas power line? Regardless of, if it's right or wrong there is no reason for belittling a new member or senior for that matter. Regards, John from downunder.

depfife 08-23-2003 12:32 PM

servo help
 
Here is some info I found in another thread.

Eric

http://www.rcuniverse.com/showthread...037&forumid=27



Originally posted by amcross

As far as the digitals, they are labeled as being for 4.8V only because they were originally intended to be gyro servos, adn the gyros are not to be exposed to unregulated 6V. Therefore the team that did the testing would've tested only at 4.8V. I have triple confirmed their maximum voltage and they are undoubtedly, definitely, WITHOUT QUESTION fine on 6.0V. In fact they are recommended in the 3PK manual with the HRS systems which REQUIRE 6V.

]

Rodney 08-23-2003 02:53 PM

servo help
 
EDFanatic's advice was not rude, just good advice.

john flynn 08-24-2003 12:25 AM

servo help
 
Rodney. your saying that calling someone stupid for suggesting a practical solution to a problem, is not rude? Throwaway remarks like Fanatics and those that defend them, are a reflection on a person's lack of intelligence, not sound advice given in good faith. All other replies to the post were answered without the need to resort to degrading remarks. Above all, I hope it doesn't deter Bill from offering his experience in further discussions. Forgive me bill for acting in your defense but I felt the need as you have assisted me on an occasion and I consider you as a new friend. Regards, John.

Smoky 08-24-2003 03:02 AM

servo help
 

Originally posted by 3DFanatic
KISS (Keep It Simple Stupid)

Go with flyboy's advice and run the 4.8.

KISS = an achronym used extensively as a friendly reminder that the simple things are often better and overlooked. Albeit looking for a problem or finding a solution.
K= keep
I=It
S=simple
S=stupid

This remark was not meant to be degrading or insulting. Just friendly Banter often used to make a point.

FWIW. achronym = For What It's Worth. :)

Smoky.

KW_Counter 08-24-2003 01:47 PM

KISS
 
Keep
It
Simple
Silly

Same thing - Less degrading.
Kudos to the Aussie for trying to keep this place FRIENDLY and helpful!!!
KW_Counter

danny03 08-27-2003 06:43 PM

diodes?
 
I realize that this may be a little off topic, but since it was suggested to install a couple of diodes to bring the voltage down from 6v to 4.8V, I thought that the purpose of diodes was to limit the flow of elec. to one direction and the purpose of resistors was to change/limit voltage. Is there something that I am missing/Forgotten over the years?

bsindel 08-27-2003 08:28 PM

servo help
 
Thanks John for picking up the cudgel on my behalf, but those sort of folks don't really put me off. However, should I happen to walk by while they are puzzling about the black goo coming out of their exhaust I will just smile and walk on by, if you know what I mean.

Danny03, you are right in that generally speaking diodes do allow current flow in only one direction. However, one of the neat things that a typical silicon rectifier diode does is that when it is forward biased, conducting current, it develps a voltage drop across it of approximately 0.62 volts and this voltage will remain fairly constant over a wide range of current flow. This characteristic makes for a very simple, inexpensive, and reliable voltage regulator. At least to an old electronics hacker like me.

You can usually obtain a spec sheet from a manufacturer which will tell you the voltage range they specify for their products.

Good Luck All
Bill

danny03 08-28-2003 12:17 PM

diode?
 
Thanks bsindel, I never knew or realized that about diodes, before long I might just become an electrical wizard from all the info that I am getting from the members here.........yea Right in my wildest dreams anyway Thanks again...

cabanestrut2002 08-28-2003 04:56 PM

servo help
 
TLAR= that looks about right

KISS isnt offensive, some of you guys are very sensitive-get real

RJChip 08-28-2003 05:58 PM

just have to add 2c worth
 

Originally posted by bsindel

Danny03, you are right in that generally speaking diodes do allow current flow in only one direction. However, one of the neat things that a typical silicon rectifier diode does is that when it is forward biased, conducting current, it develps a voltage drop across it of approximately 0.62 volts and this voltage will remain fairly constant over a wide range of current flow. This characteristic makes for a very simple, inexpensive, and reliable voltage regulator. At least to an old electronics hacker like me.

Bill

Yes, this is a common way of dropping a fixed amount of voltage, but just be sure not to get it confused (for any non-electronics enthusists) with genuine "regulation." A fully charged 6V pack running at, say, 6.75V, would drop to approx. 5.5V with two diodes in line. Then, at (near) end of capacity, battery voltage of 5.5V would be dropped to approx. 4.25V. Within specs for operation, but servos would be just a little slower.

FWIW suggestion, also: If needing to drop voltage for just one servo, consider placing diode(s) in supply line to that servo only. Thay way, there is no additional risk to Rx and other servos if diodes should fail. Also, other servos still get benefit of higher voltage if that is desired for speed/torque.

Finally, be sure to use diode(s) with high enough current rating!

bsindel 08-29-2003 07:53 AM

servo help
 
Rich, if you read my original post you would see that I suggested that the diodes be put in the power lead of the servo in question. I figured that if he knew what I was talking about he would just go ahead a try it if he needed to, and if he didn't know but was interested in finding out he would ask me a question at which time we could take the electronics discussion offline.

Bill

You never have too much fuel onboard until your aircraft catches fire.....

RJChip 08-29-2003 10:37 AM

servo help
 
Bill
Sorry, my mistake in not re-reading your first post. I replied after your second post, and I somehow completely forgot in the meantime that that was exactly what you had suggested!
Didn't mean to step on any toes.
Rich


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