Jump to content
Sign in to follow this  
RustyKnee

Mks 6125 mini with mlink fast response setting.

Recommended Posts

RustyKnee

I tried the h version, and it doesn't seem to suffer as bad. the problem is worst on slow medium speed movement and the juddering is quite apparent when using the servo test run feature of the devil pro. I will just live with 20ms frames...my thumbs aren't good enough to notice. Stu

Share this post


Link to post
Share on other sites
RustyKnee

More news…the juddering is less apparent or possably absent when I used my new 5 cell 1600mah intellect 2/3A pack….hmm. Will keep an eye on things and see if it reappears as the pack discharges. I should try it on a variable bench PSU really. Stu

Share this post


Link to post
Share on other sites
isoaritfirst

Ahhhh!!! You shouldn't be using 5 cell packs on MKS 6125 servos. The smoke will out!

Share this post


Link to post
Share on other sites
RustyKnee

hmmmm :|Spec sheet says 6v nom is fine. You are the second person I have heard say it now. Not heard or read about one who has actually done it though.

Share this post


Link to post
Share on other sites
isoaritfirst

Just be careful about 6v on spec sheets.It means 6v not 5 cell.  My understanding is that MKS does not like 5cell. But of course in the real world you may be lucky. Well do yah feel lucky, well do yah?

Share this post


Link to post
Share on other sites
RustyKnee

Got to love spec sheet woolliness. I bet the torque figures at "6v" aren't using a 4 cell :). I did a quick waggle check yesterday and they are way quick... Quicker than necessary. So I will probably chop out a cell and free up some room. Not got the cg set yet so not much extra work.

Share this post


Link to post
Share on other sites
Austin

I think the 6v spec on most servos may come from dry cell voltage, 4x1.5vSome time back I did some testing of 1400 2/3AF Intellect NiMH cells. After charge they can produce over 7v and @400mAh discharge they produce 6.5v for a long while. Not sure how this will affect servos over longer periods of time but I can't see it being good for them.My question is. Are 5 cells needed, and apart from gaining servo speed what is the benefit. More torque and power yes but these servos have enough of that at 5v anyway? 

Share this post


Link to post
Share on other sites
RustyKnee

Fresh off charge I was seeing about 7v yesterday. Just done a cellectomy and after settling for a day and waggle checks the voltage is 5.2v. I don't need the speed or torque. They are the fastest servos I have had in an f3f even at 4 cell. Positives are more room and lower current draw but will need a bit more nose lead. I will test for "steppyness" on 4 cell fast response again later. I have a regulator, but Didn't want the extra complication and reduced reliability so 4 cells it is :)Cheers guys. Stu

Share this post


Link to post
Share on other sites
satinet

I was a bit surprised that MKS released them not being able to run at LiFe voltages given that LiFe are, arguably, going to start going in a lot of gliders in the future (it is a glider servo according to MKS).  It would be strange if they were not happy on 5 cells, in terms of sales to the north american market.  As anyone who has read Rcgroups will know it is impossible to fly a glider on the north American continent with less than 5 cells in the nose.  Although of course that may be technical reasons for it.  Or maybe they will release a high voltage version for £100 a pop.....

Share this post


Link to post
Share on other sites
Woodstock

satinet said:

I was a bit surprised that MKS released them not being able to run at LiFe voltages given that LiFe are, arguably, going to start going in a lot of gliders in the future (it is a glider servo according to MKS).  It would be strange if they were not happy on 5 cells, in terms of sales to the north american market.  As anyone who has read Rcgroups will know it is impossible to fly a glider on the north American continent with less than 5 cells in the nose.  Although of course that may be technical reasons for it.  Or maybe they will release a high voltage version for £100 a pop.....
Yes, this is surprising. I thought the big trend in servos is higher voltage capacity in order to handle LiFe with no regulator, so one would expect all newer servos to be quite able to handle 5 cells no problemo..

Share this post


Link to post
Share on other sites
Woodstock

RustyKnee said:

I have a regulator, but Didn't want the extra complication and reduced reliability
I see this concern about the reliability of regualtors appearing often on the forums.  I have never heard of a regulator expriring or causing a crash.  It's just another electronic device, one of many we rely 100% on to guide our planes safely (receiver, transmitter, etc. etc.).  Almost every electric power plane uses a regulator (either as a BEC in the ESC, or as a separate power source)…. 

Share this post


Link to post
Share on other sites
RustyKnee

hi Chris. All very valid points. I wasn't saying that regs are unreliable. Just that they are another singlepoint of failure. Tried with the now 4 cell pack and the juddering is back. So set to 20ms and be done with it :).

Share this post


Link to post
Share on other sites
Sloper

Hi GuysMKS state the DS6125 range servos are happy to run up to 6v but do not recommend running them over 6v, for any length of time.I have heard about the guys in the US running them on 6.6 LiFe including the Futaba s3155 which are also recommended no more than 4.8vsurprise.gif. I will refer to them again on this issuerich

Share this post


Link to post
Share on other sites
RustyKnee

Cheers Rich, They look plenty fast on 4 cell. Stu

Share this post


Link to post
Share on other sites
satinet

t9hobbysport said:

Hi GuysMKS state the DS6125 range servos are happy to run up to 6v but do not recommend running them over 6v, for any length of time.I have heard about the guys in the US running them on 6.6 LiFe including the Futaba s3155 which are also recommended no more than 4.8v. I will refer to them again on this issuerich
What does that advice really mean though? if you take that literally you can't run it on 5cell nimh battery. They only go to 6v or under when they are just about to go flat (or under a heavy load). Even after the voltage has settled down post charge, they have a voltage way over 6v.

Share this post


Link to post
Share on other sites
jiberjaber

t9hobbysport said:

Hi GuysMKS state the DS6125 range servos are happy to run up to 6v but do not recommend running them over 6v, for any length of time.I have heard about the guys in the US running them on 6.6 LiFe including the Futaba s3155 which are also recommended no more than 4.8vsurprise.gif. I will refer to them again on this issuerich
Rich, the 3155 is rated to 6V, the 3150 isnt.  I checked before putting a 5 cell in my Needle :) 6.6V might be pushing it though.I too have jerky/juddery MKS servos, but only on the flaps.  Ailerons are fine.  This is on 5V from a uBEC.  Both the 6125 and 6125-mini show the same on two different gliders.  If I slowly apply crow, thereare judders in the flap deploying.  If I rapidly deploy crow, there is no juddering of the flaps.  It is as though the weight of the flap allows the pot to overshoot but then the servo tries to bring the flap back up to hit where it should have been, which then overshoots so the servo tried to correct and starts to oscilate.  I have managed at one point to get the flay to oscilate for some time… this is on the Xpro so I put it down to slop in the linkages and flap join.  This seem to co-incide with flap2 on the Futaba 8ch receiver (ch6)On the new Stork4 I have just finished, there isnt any oscilation but the judder is still there on brand new full fat 6125's on both chn 5 & 6 (flap 1 & 2) on a new Futaba 8ch receiver.  It is almost as if there is something rubbing which is causing the servo to stop/start.  However, the flap moves freely both with and without the servo connected to its linkage..Both flaps are cross over installations, however the ailerons on the Xpro are also cross over where as the Stork are direct link… no judder on the ailerons as I said! :)Not a problem in flight of course as I think the air loading keeps it in check, just on the bench!Other than that I am very happy with the servos…. the clevis break before the servo and thats on the mini!

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Sign in to follow this  

  • Recently Browsing   0 members

    No registered users viewing this page.

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.