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ULPower electrical system
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user9253

Joined: 28 Mar 2008
Posts: 1921
Location: Riley TWP Michigan

Posted: Thu Sep 08, 2022 9:34 am Post subject: Re: ULPower electrical system

 	  Quote: 	
		  One more question...how would I wire TWO relays with the B&C overvoltage sensor. 

I have looked everywhere I can think and I can't see that documented anywhere. 	


If you are using the original B&C over voltage device that is shown on Bob's Z-16, then wire according to Z-16.

It doesn't matter if there are one or two or three relays.  They are wired in

parallel and function as a single component.  One wire controls all.

_________________
Joe Gores

N43YX

Joined: 22 Feb 2021
Posts: 10
Location: Tulsa, OK

Posted: Thu Sep 08, 2022 10:08 am Post subject: Re: ULPower electrical system

Thank you all very much.  I appreciate it.  The diagram was exactly what I was looking for.  



This is the B&C OV kit I was planning on:

https://www.aircraftspruce.ca/catalog/eppages/08-00658.php?clickkey=8339



I'd need to order another relay.



One other question regarding buss design.  I am using a single ECU and dual redundant fuel pumps.  Per the Z diagrams, my plan is to have the ECU and at least one fuel pump powered from the battery buss.  I am only planning on a single ECU but as the switch and wiring would be a possible single point-of-failure, I am considering wiring a parallel switch providing an "alternate feed" to the ECU.  



Are there any potential problems with this?  From which buss should I power the AUX feed to the ECU and the second fuel pump?  I can't imagine a battery buss failure would be a common event, but would it be better to power it from the endurance buss?

user9253

Joined: 28 Mar 2008
Posts: 1921
Location: Riley TWP Michigan

Posted: Thu Sep 08, 2022 1:38 pm Post subject: Re: ULPower electrical system

You might consider combining features from 2 or more Z figures.

For instance, use Z-16, but add the engine bus from Z-101B.

http://www.aeroelectric.com/PPS/Adobe_Architecture_Pdfs/Z101B.pdf

The engine circuitry is drawn in pink. Using 2 switches wired in parallel is feasible.

Another option is to use a single double pole switch with the contacts wired in parallel.

_________________
Joe Gores

yellowduckduo(at)gmail.co
Guest

Posted: Thu Sep 08, 2022 2:29 pm Post subject: ULPower electrical system

I'd question the benefit of a double pole switch.

Still subject to a mechanical switch failure and also no warning if one 

pole has failed.

Two switches with separate fuses would add more redundancy although I'm 

not sure it adds much value with a single ecu unless there are two power 

sources.

Ken



On 08-Sep.-22 5:38 p.m., user9253 wrote:

 	  Quote: 	
		   



 You might consider combining features from 2 or more Z figures.

 For instance, use Z-16, but add the engine bus from Z-101B.

 http://www.aeroelectric.com/PPS/Adobe_Architecture_Pdfs/Z101B.pdf

 The engine circuitry is drawn in pink. Using 2 switches wired in parallel is feasible.

 Another option is to use a single double pole switch with the contacts wired in parallel.



 --------

 Joe Gores





 Read this topic online here:



 http://forums.matronics.com/viewtopic.php?p=507862#507862

nuckolls.bob(at)aeroelect
Guest

Posted: Tue Sep 13, 2022 5:12 pm Post subject: ULPower electrical system

 	  Quote: 	
		  

 I'd question the benefit of a double pole switch.

 Still subject to a mechanical switch failure and also no warning if one pole has failed.

 Two switches with separate fuses would add more redundancy although I'm not sure it adds much value with a single ecu unless there are two power sources.

 	


   Agreed.



   Note that Z101 uses only ONE switch to control

   an second power path to specific busses. NORMAL

   power is carried through a diode from the main

   bus. I.e. if the main bus is up, all busses

   are up.



   Otherwise, reduced energy operation protocols

   are managed with closure of one switch per bus.



   Essentially zero probability for un-manageable  loss of

   power to any bus.



 

   Bob . . .



   Un impeachable logic: George Carlin asked, "If black boxes

   survive crashes, why don't they make the whole airplane

   out of that stuff?"

N43YX

Joined: 22 Feb 2021
Posts: 10
Location: Tulsa, OK

Posted: Sun Sep 25, 2022 12:51 pm Post subject: Re: ULPower electrical system

In the wiring diagram that Bob provided, can someone please explain why I need a fusible link and fuse in series for the alternator switch?  



Also, should I feed the alternator on/off switch from the battery, endurance, or main buss?

Ceengland

Joined: 11 Oct 2020
Posts: 391
Location: MS

Posted: Sun Sep 25, 2022 1:14 pm Post subject: ULPower electrical system

On Sun, Sep 25, 2022 at 3:54 PM N43YX <awgaut(at)gmail.com (awgaut(at)gmail.com)> wrote:



 	  Quote: 	
		  --> AeroElectric-List message posted by: "N43YX" <awgaut(at)gmail.com (awgaut(at)gmail.com)>

 

 In the wiring diagram that Bob provided, can someone please explain why I need a fusible link and fuse in series for the alternator switch?  

 

 Also, should I feed the alternator on/off switch from the battery, endurance, or main buss?



	
Are you referring to the one he posted in this thread on Sept 8? If so, the 20ga link protects the 16ga wire that runs from the bus to the circuit breaker (not a fuse) in the drawing) which is typically in the instrument panel, remote from the bus. 

As to main vs endurance, kinda depends on whether it's the primary alt or the backup, and your personal philosophy. I put all my backup alt connections on my *engine* bus, because I'll have auto style injection which has high and constant current demand. Allows 'smoke in the cockpit' master-off as we're hard wired to do in training, while keeping the engine running. I don't have an endurance bus; just the ability to feed either bus from different switches (cross-tie features).

Charlie

_________________
Charlie

N43YX

Joined: 22 Feb 2021
Posts: 10
Location: Tulsa, OK

Posted: Sun Sep 25, 2022 2:57 pm Post subject: Re: ULPower electrical system

Yes, sir.  I was referring to the post of 9/8.  



Makes sense.  It protects the WIRE running to the panel CB.  I always seem to forget that basic premise.



Ceengland:  I am only running one alternator and one battery with a battery/engine buss, if that helps in deciding from where to feed the alternator switch power.  I'm thinking of just using the engine buss.

user9253

Joined: 28 Mar 2008
Posts: 1921
Location: Riley TWP Michigan

Posted: Sun Sep 25, 2022 6:20 pm Post subject: Re: ULPower electrical system

In the event of smoke in the cockpit, the pilot needs the ability to shut off all 

electrical power at the source.  Most pilots would do that by shutting off the 

master switch.  Depending on how the electrical system is wired, 

disconnecting the battery might not shut off electrical power because the 

alternator could be still be working and supplying its own field current.

It is something to keep in mind when designing the electrical system.

_________________
Joe Gores

nuckolls.bob(at)aeroelect
Guest

Posted: Mon Sep 26, 2022 3:25 pm Post subject: ULPower electrical system

At 03:51 PM 9/25/2022, you wrote:

  	  Quote: 	
		  --> AeroElectric-List message posted by: "N43YX" <awgaut(at)gmail.com>



 In the wiring diagram that Bob provided, can someone please explain why I need a fusible link and fuse in series for the alternator switch?  



 Also, should I feed the alternator on/off switch from the battery, endurance, or main buss? 	


    Most TC aircraft are fitted only with breakers

    for protection in which case, the 5A alternator

    field breaker would be mounted with its cousins

    in the 'breaker patch' and driven directly from

    the bus.



    When using fuseblocks, the busses are centralized

    in the blocks. Further, they're generally mounted

    out of sight, out of reach given that there is

    no practical reason to fiddle with fuses in flight.



    The crowbar ov protection departs slightly from

    from this philosophy because there might be electrical

    events that cause the crowbar to operate when in

    fact, no serious fault condition exists. In this

    case, it's nice to have access to ONLY that

    breaker allowing pilot reset to see if the problem

    persists. 



    Hence, the BUS needs to be EXTENDED from the

    fuseblock to the breaker. Faulting this piece

    of wire offers potential for lots of smoke.

    A fusible link limits this severity of such

    an event.



    This is a reminder that fusible links are not

    replacements for fuses or breakers. They are

    low resistance, high reliability, long fusing

    constant protection of bus extensions . . . i.e.

    conductors at risk for experiencing fault currents

    supplied by a BATTERY.



    They are used sparingly. Typically limited to

    alternator b-leads, feeders to bus-tie contactors,

    and . . . crowbar breakers located remote from

    the bus buried in a fuse block.



 

 

   Bob . . .



   Un impeachable logic: George Carlin asked, "If black boxes

   survive crashes, why don't they make the whole airplane

   out of that stuff?"

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