flyrotary@lancaironline.net Mailing List Archive

Al,

Sounds like you and I think alike (at least on this subject.) I did not mention on my previous post, but I also follow the same redundant scheme on my fuel pumps and ECU (funny that I labeled the panel ECU A and ECU B, rather than EC2...) I also used diodes at the ECU end of the two feeds (so a short in one supply line does not bring both lines down since the two EC2 supplies are connected internal to the EC2. I would not have expected the EC2 controller to put noise into the supply line, but then again I have not put a scope on a running unit yet. What level spikes have you observed? And should I consider a capacitor to absorb/dissipate potential spikes? I used Schottky diodes on the supply lines ( due to the low forward voltage drop characteristics.)

Joe

----- Original Message -----

From: Al Gietzen

To: Rotary motors in aircraft

Sent: Saturday, April 14, 2007 6:35 PM

Subject: [FlyRotary] Re: RWS ECU Switch call-out

To: Rotary motors in aircraft
Subject: [FlyRotary] Re: RWS ECU Switch call-out

A thought on the injector power supply. In my installation I use a separate

power supply for primary and secondary injectors (as well as for the coils.)

In my case primaries are wired to battery 1 and secondaries are wired to

battery 2. Even if you are using a single battery (IMO) its beneficial to

have separate wiring/switches/overload devices. If a power supply wire,

switch, overload, connection were to open there goes all supply to the

injectors (or coils.)

I agree. Fault tolerance (read reliability) is redundancy from source to use. I designed for either of any of the engine critical items (ECU, coils, injectors, fuel pumps) to operate from either of two batteries, fully isolated.

This required the use of some diodes which may have uncovered some noise issues in the EC2 - don't know for sure yet. The isolation diodes can prevent voltage spikes from traveling back to the batteries where they would dissipate.

Al