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ULPower electrical system
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N43YX

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

Posted: Mon Sep 05, 2022 5:11 am Post subject: ULPower electrical system

I'm working on an electrical design for a Waiex-B with a UL Power 350iS.  I've started with Z21 but I think it may require some modification.  I'm going with a single ECU and probably the 50A alternator upgrade (the ECU and fuel pump use 15A so the stock 30A alternator wouldn't leave a ton left for my electrical loads).  The installation manual linked below seems lacking on the electrical system in several respects.  



1) There is no OV protection



2) There is no way---CB or switch--to disconnect the alternator



I'd like to use the B&C over voltage kit, but I doubt if that is possible with the larger alternator.  At a minimum, I'd like to be able to manually disconnect the alternator.



Could someone give me some guidance and suggestions?

https://ulpower.com/content/1-engines/5-manuals/installation-checklist-v2.2.pdf

user9253

Joined: 28 Mar 2008
Posts: 1926
Location: Riley TWP Michigan

Posted: Mon Sep 05, 2022 11:50 am Post subject: Re: ULPower electrical system

The UL Power electrical installation is explained in this manual:

https://ulpower.com/content/1-engines/5-manuals/installation-manual-2022-v1.5.pdf

If overvoltage protection is desired, use Z-16 as a guide.  In fact, Z-16 also shows how to disconnect the alternator using a relay.

Since the UL Power engine appears to have a 3 phase alternator, I recommend using 3 automotive relays, one for each phase.  

Using a 3 phase contactor is a more elegant way of controlling the alternator, but automotive relays have the advantage of low price and availability.

The UL Power manual warns that the regulator (30amp only?) will be destroyed if it is disconnected from the battery.  There is no danger to the regulator if the AC is disconnected.

Best practice is to not switch the charging system on or off while the engine is running.

The 10awg wire recommended for the 68 000 μF capacitor seems big.

_________________
Joe Gores

art(at)zemon.name
Guest

Posted: Mon Sep 05, 2022 12:54 pm Post subject: ULPower electrical system

Why are you sizing your alternator for 50A? It is more typical to size the alternator for the maximum continuous load and I really wonder whether a Waiex needs 50 amps. For example, in my airplane, the autopilot servos have a max draw of 3.4 amp but a typical draw of only 1.8. Similarly, my comm radio has a max draw of 3.0 amps but a typical draw of only 0.5 and the 10 inch EFIS screen has a max draw of 2.25 but a typical draw of only 1.2.

When I did a spreadsheet of max and typical draws for all devices, I came up with 29.28 max and 18.57 typical. You can see what I did in this overview drawing for my wiring system documentation.

    -- Art Z.

On Mon, Sep 5, 2022 at 8:23 AM 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)>

 

 I'm working on an electrical design for a Waiex-B with a UL Power 350iS.  I've started with Z21 but I think it may require some modification.  I'm going with a single ECU and probably the 50A alternator upgrade (the ECU and fuel pump use 15A so the stock 30A alternator wouldn't leave a ton left for my electrical loads).  The installation manual linked below seems lacking on the electrical system in several respects.  

 

 1) There is no OV protection

 

 2) There is no way---CB or switch--to disconnect the alternator

 

 I'd like to use the B&C over voltage kit, but I doubt if that is possible with the larger alternator.  At a minimum, I'd like to be able to manually disconnect the alternator.

 

 Could someone give me some guidance and suggestions?

 

 

 https://ulpower.com/content/1-engines/5-manuals/installation-checklist-v2.2.pdf

 

 

 

 

 Read this topic online here:

 

 http://forums.matronics.com/viewtopic.php?p=507828#507828

 

 

 

 

 

 

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My blog: CheerfulCurmudgeon.com

Wisdom is knowing what to do next. Virtue is doing it. -- David Starr Jordan

user9253

Joined: 28 Mar 2008
Posts: 1926
Location: Riley TWP Michigan

Posted: Mon Sep 05, 2022 3:59 pm Post subject: Re: ULPower electrical system

My RV-12 has a 20 amp alternator. The plane uses less than 10 amps.

_________________
Joe Gores

N43YX

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

Posted: Mon Sep 05, 2022 4:14 pm Post subject: Re: ULPower electrical system

The ULPower engine is electrically dependent.  It uses ~15 A at full throttle and about 12.5 A at cruise power.  So, that gets subtracted off the top.  Here is my list of electrical loads (first number is maximum; parenthetical numbers are typical):



Engine				15 (13)		

Battery contactor		0.8		

SkyView				3.6 (2.6)	

Intercom				0.1		

AV-20S				0.5		

iPad					0.4		

Strobe lights		        2		

Seat Heater			10 		

Nav lights				0.6		

Com					2 (0.2)		

Xpnder				0.4		

CO Monitor			0.1		

ADS-B receiver			0.1 		

AP					3.3 (2)		

Landing/taxi light		2.5		

					35.3 	continuous



Flaps are an additional 5 A, but since it is a (very) intermittent load I didn't include them.  With traditional alternators, I have read that you should plan on loading them at ~80% capacity.  Not sure that this applies to PM alternators.

user9253

Joined: 28 Mar 2008
Posts: 1926
Location: Riley TWP Michigan

Posted: Mon Sep 05, 2022 7:01 pm Post subject: Re: ULPower electrical system

The 10amp seat heater can be subtracted.  It is not a continuous load, especially in Tulsa OK.

If the alternator can not maintain the voltage, It won't hurt to let the battery discharge for a few minutes while heating the seat.

Percentage of safe alternator load depends on its temperature.  If kept cool, it can even be operated at more than 100 percent.

_________________
Joe Gores

Ceengland

Joined: 11 Oct 2020
Posts: 391
Location: MS

Posted: Mon Sep 05, 2022 7:25 pm Post subject: ULPower electrical system

Not a safe assumption.  Some use seat heat to replace cabin heat. In those cases,  load would be continuous,  when it's needed. 

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 On Sep 5, 2022, at 10:04 PM, user9253 <fransew(at)gmail.com (fransew(at)gmail.com)> wrote: 	  Quote: 	
		    	  Quote: 	
		  --> AeroElectric-List message posted by: "user9253" <fransew(at)gmail.com>The 10amp seat heater can be subtracted.  It is not a continuous load, especially in Tulsa OK.If the alternator can not maintain the voltage, It won't hurt to let the battery discharge for a few minutes while heating the seat.Percentage of safe alternator load depends on its temperature.  If kept cool, it can even be operated at more than 100 percent.--------Joe GoresRead this topic online here:http://forums.matronics.com/v --> http://forums.matronics.comhttp://wiki.matronics.comhttps://matronics.com/contribution

_________________
Charlie

N43YX

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

Posted: Tue Sep 06, 2022 3:03 am Post subject: Re: ULPower electrical system

Exactly.  I'm forgoing an exhaust shroud heater for a couple of different reasons and I am just using electric seat heat.

user9253

Joined: 28 Mar 2008
Posts: 1926
Location: Riley TWP Michigan

Posted: Tue Sep 06, 2022 7:39 am Post subject: Re: ULPower electrical system

OK, I was wrong. Include 10 amps continuous for electric seat heat.

_________________
Joe Gores

kenryan

Joined: 20 Oct 2009
Posts: 426

Posted: Tue Sep 06, 2022 8:04 am Post subject: ULPower electrical system

Or consider a heated vest with its own power supply.



On Tue, Sep 6, 2022 at 7:45 AM user9253 <fransew(at)gmail.com (fransew(at)gmail.com)> wrote:



 	  Quote: 	
		  --> AeroElectric-List message posted by: "user9253" <fransew(at)gmail.com (fransew(at)gmail.com)>

 

 OK, I was wrong.  Include 10 continuous for electric seat heat.

 

 --------

 Joe Gores

 

 

 

 

 Read this topic online here:

 

 http://forums.matronics.com/viewtopic.php?p=507838#507838

 

 

 

 

 

 

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 eferrer" target="_blank">http://forums.matronics.com

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user9253

Joined: 28 Mar 2008
Posts: 1926
Location: Riley TWP Michigan

Posted: Wed Sep 07, 2022 7:29 am Post subject: Re: ULPower electrical system

Below is a drawing showing 3 relays that can shut off the charging system right at the source.

Substitute the 3 relays for the single relay shown in Z-16.  Only one flyback diode is needed for all 3 relays.

3 PHASE DYNAMO.png

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_________________
Joe Gores

nuckolls.bob(at)aeroelect
Guest

Posted: Wed Sep 07, 2022 8:46 pm Post subject: ULPower electrical system

At 10:29 AM 9/7/2022, you wrote:

  	  Quote: 	
		  --> AeroElectric-List message posted by: "user9253" <fransew(at)gmail.com>



 Below is a drawing showing 3 relays that can shut off the charging system right at the source.

 Substitute the 3 relays for the single relay shown in Z-16.  Only one flyback diode is needed for all 3 relays. 	


   You only need two relays to completely shut down

   the 3-phase supply.



 

 

   Bob . . .



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

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

   out of that stuff?"

Eric Page

Joined: 15 Feb 2017
Posts: 247

Posted: Wed Sep 07, 2022 9:56 pm Post subject: Re: ULPower electrical system

 	  user9253 wrote: 	
		  The UL Power manual warns that the regulator ... will be destroyed if it is disconnected from the battery. 	


 	  nuckolls.bob(at)aeroelect wrote: 	
		  You only need two relays to completely shut down the 3-phase supply. 	


Thinking out loud here...  If the OVP sensor trips, then isn't it safe to assume that the regulator has already failed?  If so, then why would we be concerned about damaging it by disconnecting it from the battery?  Is there some other reason not to use a single relay to disconnect the regulator's output from the bus rather than multiple relays to disconnect the alternator's phases from the regulator?

N43YX

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

Posted: Thu Sep 08, 2022 12:33 am Post subject: Re: ULPower electrical system

I am aware of at least two people that wired it as you described, Eric.  I guess a downside (if I am understanding correctly) of this arrangement would be that you wouldn't want to manually disconnect the alternator via the switch for fear of harming the regulator, but I can't see why you would want to do that anyway unless there was a problem.    With two relays wired prior to the regulator, you would be able to shut it down manually without harming the regulator, correct?



Also, the B&C OV kit is only rated for 30 amps.  I found these that are rated for 60 A.  Would this work?  I'm assuming they can be mounted FWF.

60A relay SPDT.pdf

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user9253

Joined: 28 Mar 2008
Posts: 1926
Location: Riley TWP Michigan

Posted: Thu Sep 08, 2022 4:22 am Post subject: Re: ULPower electrical system

I thought about using just 2 relays.  But what if the dynamo windings are

connected in "Y" with the center grounded?  Or is that highly unlikely?

_________________
Joe Gores

user9253

Joined: 28 Mar 2008
Posts: 1926
Location: Riley TWP Michigan

Posted: Thu Sep 08, 2022 4:38 am Post subject: Re: ULPower electrical system

 	  Quote: 	
		  If the OVP sensor trips, then isn't it safe to assume that the regulator has already failed? 	


Could be, but Not necessarily.  Depending on the the aircraft wiring, there could be resistance causing a voltage drop that

the regulator interprets as low system voltage.  Thus the regulator would increase output voltage and cause an overvoltage event.

That problem can be minimized by not putting a load on the voltage sense wire.  But it has happened.

_________________
Joe Gores

Eric Page

Joined: 15 Feb 2017
Posts: 247

Posted: Thu Sep 08, 2022 6:07 am Post subject: Re: ULPower electrical system

 	  N43YX wrote: 	
		  With two relays wired prior to the regulator, you would be able to shut it down manually without harming the regulator, correct? 	


It sure sounds that way.



 	  N43YX wrote: 	
		  Also, the B&C OV kit is only rated for 30 amps.  I found these that are rated for 60 A.  Would this work?  I'm assuming they can be mounted FWF. 	


Yep, those would work.  That sort of relay is mounted in vehicle engine bays all the time.  The datasheet says they're rated up to 125°C (257°F).  Be sure to order them with a mounting tab on the back.



More thinking out loud...  I'll bet that a 30A relay would be more than sufficient since the alternator's 50A max output would be evenly split across the three phase wires (~17A per wire).  Bob, am I out to lunch here?



 	  user9253 wrote: 	
		  ...what if the dynamo windings are connected in "Y" with the center grounded? Or is that highly unlikely? 	


I'll defer to Bob on this one; I don't know if there are any alternators or stators wired in wye configuration.

N43YX

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

Posted: Thu Sep 08, 2022 6:41 am Post subject: Re: ULPower electrical system

You guys are great!  Thanks for the help.



I think I'll go with the two relays wired before the R/R, so I can have manual control of shutting off the alternator.  If I could use the 30 A relays from the B&C kit, that would be even better.  I'd like to hear Bob's thoughts, too, on using the B&C relays.



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.

nuckolls.bob(at)aeroelect
Guest

Posted: Thu Sep 08, 2022 6:48 am Post subject: ULPower electrical system

 	  Quote: 	
		  More thinking out loud...  I'll bet that a 30A relay would be more than sufficient since the alternator's 50A max output would be evenly split across the three phase wires (~17A per wire).  Bob, am I out to lunch here?



 

 user9253 wrote:

 > ...what if the dynamo windings are connected in "Y" with the center grounded? Or is that highly unlikely?



 I'll defer to Bob on this one; I don't know if there are any alternators or stators wired in wye configuration. 	


    There are some legacy products being offered as

    spares which are y-wound, but I'm not aware of

    any modern y-wound devices. In any case, y-wound never

    grounds the center. Some designs bring that

    node out as a AUX terminal . . . this is the connection

    that used to drive the "S" terminal on the legacy

    electro-mechanical regulators.



    Current production B36 and B55 alternators at

    Beech still have an AUX terminal but it hasn't

    be used in decades.



    30A relays are plenty big . . . especially

    given the fact that they're switching AC

    current.



 

   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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nuckolls.bob(at)aeroelect
Guest

Posted: Thu Sep 08, 2022 9:26 am Post subject: 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.



 

 	


    See attached



 

 

   Bob . . .



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

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

   out of that stuff?"

3-Phase_PM_Alternator_Control_and_OV_Management.pdf

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