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Old Feb 29, 2012, 05:37 PM
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Mendo's Avatar
United States, CA, Ukiah
Joined Dec 2011
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I have a total of 28 of these servos and have not had one bad one yet. I have run them at 4.2v and 5v as well. I did notice that at 5v they ran a bit warm so now I diode the 5v most bec's put out down to 4.2-4.3 volts and have had great results. Nothing but good to say about these, Ill be buying more!
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Old Mar 09, 2012, 07:55 AM
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BatLaw's Avatar
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Joined Jan 2005
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It would be helpful to pull this thread to the top again as I think these servos are pretty good. I've used them in a 19 in. w/s depronised Frog Redwing and as it comes within a number of threads I've put a short build log on my blog. Take a look.
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Old Mar 09, 2012, 08:27 AM
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axelen's Avatar
Israel
Joined Dec 2006
771 Posts
Since I got 7 I decided to try and replace one of the servo's motors with a bigger one,
from a cheapo linear HK servo.

new motor's resistance is (as I recall) 2.5ohm less, but the servo
runs at the same speed. torque has increased nicely.

weight went up to 2.2gr

I don't have the camera here, so will post pics later and do a torque test.
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Old Mar 09, 2012, 08:32 AM
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too bad theyve been BK for months now. i was lucky to grab a few before the reseller/hoarders scooped up the supply. i cant see too much value in mods that increase weight though. there are several others in the 2g range that cost less and have more torque.
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Old Mar 09, 2012, 08:58 AM
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Israel
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Update :
upgraded motor servo torque - checked how much it can push at
the end of the long servo horn (the one with 3 holes at each end)

Orig servo did ~32gr
Upgraded servo did >400gr

I can't check it as my 'heavier' scales only go up to 200gr.. zeroing them with 198gr on them allows you to measure
(not very accurately, but never mind) up to 398gr... and I got "over load" on the scale screen..
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Old Mar 09, 2012, 08:59 AM
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Quote:
Originally Posted by dave1993 View Post
too bad theyve been BK for months now. i was lucky to grab a few before the reseller/hoarders scooped up the supply. i cant see too much value in mods that increase weight though. there are several others in the 2g range that cost less and have more torque.
The moded servo will be used as a tail servo for 120sized CP heli...

More over, all other cheap linear/non linear servo's are crap. EXEPT the spectrum ones, which are not digital.
so for me all other servos are not usefull, and the spectrums are today at 12$



EDIT :
Orig servo + horn (no screw @ horn) = 1.945gr
Moded servo + horn (no screw @ horn) = 2.225gr

so it's only .3gr more..
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Last edited by axelen; Mar 09, 2012 at 09:08 AM.
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Old Mar 09, 2012, 12:41 PM
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i suppose if you do get 10x more torque for 7% heavier its a good deal. for me weight is an over-riding factor. after getting mine below a gram they compete with expensive and hard to use actuators. not to mention more torque.
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Old Mar 09, 2012, 05:18 PM
ancora imparo
jj604's Avatar
Melbourne, Australia
Joined Jul 2005
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Just be careful that the electronics can cope long term. All that torque has to come from somewhere and the somewhere is now a massive increase in current through the new lower resistance motor.

You may find the driver stage now burn out easily.

Just worth being aware of.
Quote:
Originally Posted by axelen View Post
Update :
upgraded motor servo torque - checked how much it can push at
the end of the long servo horn (the one with 3 holes at each end)

Orig servo did ~32gr
Upgraded servo did >400gr

I can't check it as my 'heavier' scales only go up to 200gr.. zeroing them with 198gr on them allows you to measure
(not very accurately, but never mind) up to 398gr... and I got "over load" on the scale screen..
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Old Mar 09, 2012, 05:27 PM
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Quote:
Originally Posted by jj604 View Post
Just be careful that the electronics can cope long term. All that torque has to come from somewhere and the somewhere is now a massive increase in current through the new lower resistance motor.

You may find the driver stage now burn out easily.

Just worth being aware of.
Yes, you are right. This is a point of concern, if I burn out the board (servo amp)
I'll have to replace it with a WK one (an it's potentiometer). Im hoping that
I won't use all that power on the tail, so the servo will not burn out.
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Old Mar 09, 2012, 05:31 PM
ancora imparo
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Melbourne, Australia
Joined Jul 2005
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By the way, these are the manufacturer of this servo but unfortunately they do not appear to have any more data about this servo than is on this page.

http://www.pz-servos.com/en/products...etail&P_Id=798


Quote:
Originally Posted by axelen View Post
Yes, you are right. This is a point of concern, if I burn out the board (servo amp)
I'll have to replace it with a WK one (an it's potentiometer). Im hoping that
I won't use all that power on the tail, so the servo will not burn out.
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Old Mar 09, 2012, 05:56 PM
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New York
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that is one cool looking servo. looks easy to do too. hmmm.. 0.3grams. now you got me thinking about swapping a few out with my cheapo 6mm pagers just so i can harvest some of the 5230 4mm for tiny planes. anybody know how many ohms for the stock 4mm?

btw bigger motors dont have to draw a lot. i got little 4mm tail motors from toy heli that draw 4x more than some of my 6mm ones.
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Old Mar 09, 2012, 06:09 PM
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Israel
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Thanks for the info about the manufacturer

Yap Dave, this is quick and easy.
p.s : you need to reverse the polarity of this motor, or you will have to also swap two wires from the potentiometer (and get
a reversed servo, like I did).

just measured the motors :
Orig:
10.4ohm
4mm diam'
8mm can length
0.42gr (with plastic pinion gear)

Repacement :
8.7ohm
4mm diam'
12mm can length
0.735gr (with plastic pinion gear)
These came off some crap "Assan" linear servos.
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Old Mar 09, 2012, 06:36 PM
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thanks. so theres probably little difference in current. i would not worry about the drive transistors too much. smaller motors saturate much earlier than big ones and those drivers are often 4x-8x overdesigned from what i found testing to destruction.

my 6mm are only 0.4 gram more than my 4mm so im going to give that a try. looks like ill have to chop off a bit more than you.
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Old Mar 09, 2012, 06:45 PM
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Israel
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Quote:
Originally Posted by dave1993 View Post
thanks. so theres probably little difference in current. i would not worry about the drive transistors too much. smaller motors saturate much earlier than big ones and those drivers are often 4x-8x overdesigned from what i found testing to destruction.

my 6mm are only 0.4 gram more than my 4mm so im going to give that a try. looks like ill have to chop off a bit more than you.
hmm..
I'm not sure 6mm would fit w/o cutting the main body..
which in turn will make it harder to place the motor at the correct spot.
But then again, if you managed to get this servo down to 1gr, your up
for the job

Also, the end weight delta will be < 0.4gr since you will be taking material out of the body and back cover of the servo, from my weight
tests today I noticed the back cover part I took off is ~0.03-0.04gr. so you prob' end up with +0.35

would be interesting to see the difference in your setup
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Old Mar 09, 2012, 08:46 PM
ancora imparo
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Melbourne, Australia
Joined Jul 2005
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Dave, not sure that will be true.
Quote:
Originally Posted by dave1993 View Post
thanks. so theres probably little difference in current.

Well the big increase in torque has to come from somewhere! The voltage hasn't changed, the gears haven't changed and the speed was observed to stay the same (no change in mechanical advantage) so the current must have increased significantly to increase the force..

i would not worry about the drive transistors too much. smaller motors saturate much earlier than big ones and those drivers are often 4x-8x overdesigned from what i found testing to destruction.

I think that's probably the answer. The output stage has FETs that can cope with significantly more current than the original motor. Nice.
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