Oil temp Indicator Increases when AP engaged..??

[mhatfield]

Hi Everyone.. I know this sounds a bit crazy, but even when I am not 100% sure ..It seem that when I engage the AP the Oil temp raises over the normal limits, and when i disengage the AP it goes back to normal...  it sounds to me like some king of induction in to the oil temp wire...

Can any one share any ideas or experience on this regard..??

thanks in advance

 

[dynonsupport]

The servos draw 2-4A each depending on their size. This extra draw pulls more current from the alternator. If your ground is bad on your engine, this will cause the oil temp to raise.

Is this a D10A/D100 or a SkyView system? What kind of engine, and what kind of plane?

 

[mhatfield]

Hi

D180 + AP74 +2 small servos config.  Colyaer Martin 3 with Rotax 100 ULS...

But Ground theory Makes a lot of sense to me...I will look at it closer this next weekend...And comment on it next monday

Thanks for the support

 

[mhatfield]

No success was achieved...  i double checked the grounding on the engine and everything was ok...i also added an additional Grounding line direct to the negative pole of the battery. the problem persist and if i am not crazy it seems to be worst...

The config is as follows...

Colyaer Martin 3 (pusher, 100% composite) .... Rotax 912 ULS 100 hp

Dynon 180 + AP74 + 2 servos (small ones)

Any Ideas??? what else should I look at.....
The Oil temp sensor line as well as all other engine sensors lines runs together (thru the same route) with the Servo DSAB BUS and power lines ....I guess this may be part of the problem... what do you think...

Thanks in advance

 

[dynonsupport]

This still sounds like grounding.

I'm not sure how you ran an additional grounding line, but unless this is a zero gauge cable, it generally doesn't do anything for grounding issues since it's just a small wire in parallel with another enormous wire.

You can check if this has anything to do with the servos by changing loads on the plane in other ways. Turn on landing lights, heated pitots, or transmit on the radio, and I bet you'll see oil temp changes. With this data you'll know if it really is just the servos, or any electrical load that causes an issue.

Generally running wires like this in a bundle with others doesn't cause any issues.

 

[mhatfield]

Ok, I will Double Check everything related to Grounding ...Basically I agree with you ....I will follow you advice and see what can i find....

I'll come back to you with news soon...

Regards & happy landings