Ems ground and airframe ground

Re: Ems ground and airframe ground

by Richard Boslaugh » 9 years ago

Richard Boslaugh

9 122 84

I suspect a drawing error in the Rotax diagram shown in this thread. (lower right hand corner). It should show the ground side of aircraft
load going to aircraft ground not to EMS ground.There are available many discussions concerning the proper grounding for common electrical loads and avionic loads.

Re: Ems ground and airframe ground

by Rob Seaton » 9 years ago

Rob Seaton

3 1.32k 251

I don't see the error Richard,(chapter 24-00-00 page 28 912iS installation manual)
airframe ground should go to:

• regulator B
• master switch
• terminal #4 Back-up switch
• terminal #4 Start-power switch

Re: Ems ground and airframe ground

by stephen gong » 9 years ago

stephen gong

16 18 4

Hi Rob,
Yes,but we connect the wirings follow the install manual,it need we turn on backup battery switch and master switch at the same time.avionics equipment(eg.screen,radio) have power,Because Aircraft load connect to Reglerplatte A(Ems ground).it can't form a loop.negative pole(ems ground)stop at fuse box,it doesn't connect to engine or battery.
we tried to connect to Reglerplatte B,then connect to Aircraft ground,it can work like you said.So I don't know what is wrong.

Re: Ems ground and airframe ground

by Richard Boslaugh » 9 years ago

Richard Boslaugh

9 122 84

Hello Stephen and Rob. As I look at the diagram provided in Stephens opening page of the thread, and locate the symbol 'aircraft load"
I see pin two of load connected to 12v buss. When I follow pin one of load to the right. down the page, slight angle to the right, I end up at Ems ground. From Stephens comments it appears that He recognized that, wired as per the schematic and found the backup battery
switch had to be on to get the ems and aircraft grounds connected together in order that the engine display system would be on for engine start. If this was the sequence of events I would have expected some smoke. Perhaps the Rotax electrical design team build in a fail safe
circuit.

Re: Ems ground and airframe ground

by Rob Seaton » 9 years ago

Rob Seaton

3 1.32k 251

I dont have young eyes anymore so I cant see your drawing (is that blue line a wire?)

the airframe ground should not be connected to regulator A, that should be totally isolated and independent.
Did you perform this test from the installation manual?

ContinuityCheck.jpg (You do not have access to download this file.)