Mailing List flyrotary@lancaironline.net Message #61117
From: steve Izett <flyrotary@lancaironline.net>
Subject: Re: [FlyRotary] Re: actual current use by a rotary?
Date: Fri, 4 Jul 2014 08:58:34 +0800
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Hi Charlie

The little plug in ammeter is a cheap digital (in lies the problem - certainly not accurate RMS)
I use walbro pumps and I think I have the higher capacity which I realise now are way overkill and just suck more electrons than necessary.

Steve Izett

On 3 Jul 2014, at 9:56 pm, Charlie England <flyrotary@lancaironline.net> wrote:

Thanks to Dave L for the 2nd opinion  :-)  verifying current loads, and to Steve, for additional info.

You mentioned using an inexpensive plugin meter for current measurement. Is it analog, or digital? If it's analog, it's probably doing a pretty good job of averaging the current.

Charlie


On 7/1/2014 10:13 PM, Stephen Izett wrote:
Charlie

Don’t know if it is wise but I have wired our electron traffic management as follows:
1. A Main 32 way blade fuse block which is broken into two busses: A & B being -
(The blade fuse block enables me to patch a current meter to any circuit to see whats happening. Helpful when setting up or trouble shooting but just nice and compact otherwise BUT I can’t just re-energise a circuit like with circuit breakers, though blade size circuit brakes do exist nowadays. This main fuse block is mounted directly below main system switches so is very accessible)

A. FLIGHT CRITICAL (16 fuses) fed by a keyswitch:
EC2(A), EC2(B), EM3, O2, Prop Pitch, Engine Fuel Pres Pump, Engine Backup Fuel Pres Pump, Fuel Transfer Pump, Backup Fuel Transfer Pump, Pri Fuel Injectors, Sec Fuel Injectors, Leading Coils, Trailing Coils. 
Notes 1. All engine fuel is fed from a header tank of 8 gallons with the transfer pumps feeding the header from the main wing tank
Note 2. Separate power and return feeds to Pri and Sec Inj & Leading and Trailing Coils, fuel pumps.

B. AVIONONICS (16 fuses) feb by Avionoics master switch:
RHS Dynon EFIS, FHS Dynon EFIS, Flight Computer of my own, Com Radio, Transponder, Autopilot servos, Position Lights, Strobe Lights etc,

C. LANDING GEAR PUMP switched through seperate breaker (this mongrel draws ~30 amps)

Our airplane is plastic so return lines are very important. We have separate main return paths - quiet and noisy.

Steve

 
On 2 Jul 2014, at 10:08 am, Charlie England <flyrotary@lancaironline.net> wrote:

Wow, Steve, that's great detailed info; I was just hoping to get the total. I was expecting the injectors to draw more than the coils, but with all the coils together under 5 amps (and even better for the injectors), then my wiring architecture can get a lot simpler.

Many thanks,

Charlie

On 7/1/2014 7:19 PM, steve Izett wrote:
Hi Charlie

I think these are in the ball park but not measured under flying conditions only idle.

ENGINE

EC2                                          .3

EM3                                         .5

COILS (D585)                          5

INJECTORS (Renesis)             2

FUEL PRESSURE PUMP  x 1  8.4

FUEL TRANSFER PUMP x 1  1.6

O2 SENSOR                             0.6      

Total Engine                            18.4

Steve Izett

On 2 Jul 2014, at 5:08 am, Charlie England <flyrotary@lancaironline.net> wrote:

Has anyone with an ammeter installed measured their engine's actual current draw (controller, injectors, plugs, fuel pump) with everything but the engine shut down, and the alternator offline? IIRC, Bernie Kerr once did a battery duration test & discontinued after ~40 minutes, but I don't recall seeing any actual current measurements.

Thanks,

Charlie 





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