PDA

View Full Version : servo power requirements..



rao
11-15-2005, 11:30 PM
people I got this off lynxmotion..

Servo Power Requirements
Author: Jim Frye

Have you ever wondered what the limits are to servo power? Well, I have been doing some research in this area and have found some interesting facts. The servo is rated for 4.8 to 6 volts. This is representational of 4 AA NiCad batteries for 4.8 volts, or 4 AA Alkaline batteries for 6 volts. However the servo is an analog device, which means there is a certain amount of tolerance inherent to the design. A rep from Hitec has assured me that the electronics don't smoke until about 12 volts is applied. I have also found that it is considered very common for some remote control race car folks to power the servo directly from the 7.2 volt sub-C battery pack used by the drive motor. Also, the servo is quite a bit faster, which can result in more torque when moving an item with more mass. If anyone has any useful information on measuring rotational torque using a simple cheap fixture I would love to hear from you.

Below is a list of servo supply voltages and the estimated torque values extrapolated from the 4.8 vdc and 6.0 vdc specs provided from Hitec. Of course, these are just estimates based on limited technical specs from Hitec, your mileage may vary...

Ratings for a Hitec HS-422 Standard Servo
-20% Rated voltage + 20% +50%
4.8 vdc=46 oz/in | 6.0 vdc=57 oz/in | 7.2 vdc=68 oz/in | 9.0 vdc=86oz/in

The really great part to using the 7.2 volt packs are their availability. Lynxmotion has 7.2 volt NiCad or NiMh packs for $20.00, we also carry battery chargers as well. You can even get the quick disconnect plugs to wire onto your robot.

Disclaimer Use this information at your own risk! I have several robots using the 7.2 volt battery packs, including a Hexapod II with 12 Futaba 9202's. It is strong enough to do a one handed pushup, with no hesitation. I trust the electronics enough to risk $720.00 worth of servos. But don't even complain to me if you blow something up. ;-)

ice
11-16-2005, 08:51 AM
I run mine safe at 6v.
You can run them at a higher voltage,but i guess ,at a price.
Maybe reduced servo life

vikas
11-16-2005, 11:11 AM
Id have no problems if servos were Cheap ( sadly they are not ) . Why can you simply 5v at a higher current rating ??? .

subot_robot
11-16-2005, 04:22 PM
Hi,
Are any servo motors available in India? Either imported or locally manufactured. If yes can any body give more info about that. Or is it feasible to make our own servo from low rpm high torque dc motor?

Regards
Subot_robot

rao
11-16-2005, 10:31 PM
I have just the thing you asked for subot.... I came around it yesterday while going through the lynxmotion site...


here is the link...

http://www.lynxmotion.com/images/html/ht01.htm

see if this helps..

Rao

subot_robot
11-17-2005, 10:42 AM
Thanks Rao, the custom servo is great. Have anybody built a custom servo?

Regards
Subot_robot

bug
01-02-2006, 01:35 AM
Every now and hen i come across the word servo motors...

but i've never come across ne shop selling this good in bombay atleast...i often go ro bombay for buying stuffs...

can ne1 plz tell me a place where i can but a servo motor...not the lynxmotin.com..i donna want to import it....

and by the way do servo's perform + or - 90 degree task i mean + or - 2790 task maximum or they do have intermediate steps.

melchi
10-23-2007, 06:20 PM
om electronics hobby center had a servo motor - they were asking about 700 bugs for it.

allbits
10-23-2007, 06:52 PM
I know i am posting an irrelevant post...

but

700 bugs??
how am i going to catch them?? :roll:

docel
10-24-2007, 02:10 AM
Catch a pair 'n breed 'em Jobin :!: :lol: :lol: :lol:
Jokes apart, if those are the dirty grey kind , then they are of the "local" make freshly doled out by VEGAkit.
They are as useless as their geared motors.

Why buy junk when fresh imported stuff is available in India :?: :?: :?: