MKS DS92A+ & Brown-Outs

[scallybert]

Quite tidy by my standards...

[Gryphon Polaris BEC is in the middle of the L/H side.]

[cjcj1949]

When you decouple what you do is to provide a voltage source for the device that wants the power. The voltage source must be very close to the device. Putting one capacitor in, especially a large one isn't better than putting a small one close or in the servo. The alternative is to separate the high current side and the computer side by feeding from separate power supplies. Our power distribution system is very old and not designed for high power digital servos, especially ones that are not properly decoupled. MKS do separate power supplies which might help. It's one for each servo. They cost about £5 each. I'd like to see what your rx voltage looks like, especially if a big capacitor doesn't hold it up. You could also try a simple bodge which is to wrap the positive voltage feed wire to each servo around a ferrite core. Only one wire should be fed through so you'll have to take the wire out of the servo plug.

Which part of London are you?

[scallybert]

The alternative is to separate the high current side and the computer side by feeding from separate power supplies.

Which is what I have done. While saving weight. It works well, and I'm pleased....

Which part of London are you?

UCL.

[Bronek]

Re: MKS DS92A+ & Brown-Outs

Very interesting thread. Perhaps this explains my fried servo MKS DS95 (running from Koby 40 with AR7200BX, no sats)

[cjcj1949]

Have you established if the problem is high current existing as a DC condition causing long brownouts or short peaks causing interference or reset of the rx? You can probably usefully reduce the size of the SBEC supply to the servo side. The smaller the supply current the slower the servos will respond under heavy load, but the less likely they are to overheat and die. Most digital servos seem designed to increase their current beyond the safe operating area. The only stall current limited servos I've seen are henge, HK sell a servo with the same spec. I have only looked at 450 cyclics, so there may be others. I think this is an area of design that could be improved on. Current limit should be applied after a short time and when servo motor temperature gets critical. Escs do it and lots of chips like the 1S lipo charger chip that costs 50p in one offs. For 3D usage it would need an audible warning first.

[Bronek]

Re: MKS DS92A+ & Brown-Outs

Have you established if the problem is high current existing as a DC condition causing long brownouts or short peaks causing interference or reset of the rx?

in my case it was not a brownout, servo seemed to lose strenght while in the air, very fast, then shorted. Black wire fried on the whole length. I assume inadequate power from Koby might have something to do with it, plus possibly other factors. Will run these servos from BEC 10A from now on.

[scallybert]

Have you established if the problem is high current existing as a DC condition causing long brownouts or short peaks causing interference or reset of the rx?

I believe it's the latter.

[Ade_Law]

Resurrecting another old thread!

what's the current (pun most definitely intended) situation here? Has anybody tried a zener (voltage limiting) diode as well as a capacitor?

Seeing as Scallybert had tried a high power BEC and still had issues until he split the power supply to the servos from the one that supplied the rx it defo looks like noise on power issue rather than voltage drop issue.

[Jez N]

Seeing as Scallybert had tried a high power BEC and still had issues until he split the power supply to the servos from the one that supplied the rx it defo looks like noise on power issue rather than voltage drop issue.

Errrrr

Scotty: Shunt the deuterium from the main cryo-pump to the auxiliary tank.

.............

Never had issues with my ds92a's

😊

[scallybert]

Never had issues with my ds92a's

Nor I with my DS95s.

However, these are DS92A+s, and there was definitely a problem.

[cjcj1949]

Sounds like tritium is needed. Chinese are going to corner the market.

[Mike Sanders]

It's overloading the dilithium crystals Captain!

[laserfish]

Check inside servos , shorting between alloy case and solder connection for servo wires has been found on Turnegy copies.
Excess solder on joints and no insulation !

[scallybert]

Check inside servos , shorting between alloy case and solder connection for servo wires has been found on Turnegy copies.
Excess solder on joints and no insulation !

These are pukka MKS, and I'm not convinced the symptoms are consistent with that. And the DS92A+ have plastic tops & tails (unlike 95s).