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Switched voltage generator

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Paul Eckenroth

Joined: 29 Jun 2010
Posts: 14

Posted: Sun Jun 12, 2022 4:12 pm Post subject: Switched voltage generator

I need suggestion for a switched Voltage and current regulator to be used with a PM generator.  I have a Revmaster engine with a burned stator which I am replacing.  The stock voltage generator is a shunt type.  I see plenty of switching voltage regulators on line but they all look like they were designed for use on a printed circuit board, not for the firewall of a airplane.  Thanks



Paul

user9253

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

Posted: Sun Jun 12, 2022 6:50 pm Post subject: Re: Switched voltage generator

I use a John Deere voltage regulator that  I bought from eBay for my Rotax 912ULS PM dynamo.  eBay item number:255349413368 costs $20.

I mounted it with heat conductive paste between metal surfaces.  I also cool it with a blast tube and shroud.

_________________
Joe Gores

Paul Eckenroth

Joined: 29 Jun 2010
Posts: 14

Posted: Mon Jun 13, 2022 7:49 am Post subject: Re: Switched voltage generator

Thanks Joe.  Is this a switching type of regulator.  My original stator burned up due to heat generated and I want to make sure I don't repeat this.  It is my understanding that the shunt type regulator works by grounding the generator when the needs of the battery are fulfilled.  This has to add to the heat produced by the generator which is a real problem for the Revmaster stator.  I am hoping that a switching type regulator will keep the stator cooler.



Paul

skywagon185(at)gmail.com
Guest

Posted: Mon Jun 13, 2022 11:23 am Post subject: Switched voltage generator

Stator Burn up.....



Some of the newer chemistry batteries have such low internal resistance that they can "take" huge amounts of charging amps from the alternator at engine idle; low rpms.

Most alternators are built to supply fairly low amperage at idle BUT are capable of putting out large amounts if the external load is very low resistance.

The problem;  The alternator is mainly cooled by air driven by its built-in fan system. At idle, the heat generated by high amps is greater than the air flow can handle. Thus, items inside the unit start to overheat and fail.

So, just beware if you are using a battery of this type.....

PS: there are special alternators and regulators that are designed to handle this sort of charging situation....

On Mon, Jun 13, 2022 at 8:51 AM Paul Eckenroth <jeckenroth(at)nbn.net (jeckenroth(at)nbn.net)> wrote:



 	  Quote: 	
		  --> AeroElectric-List message posted by: "Paul Eckenroth" <jeckenroth(at)nbn.net (jeckenroth(at)nbn.net)>

 

 Thanks Joe.  Is this a switching type of regulator.  My original stator burned up due to heat generated and I want to make sure I don't repeat this.  It is my understanding that the shunt type regulator works by grounding the generator when the needs of the battery are fulfilled.  This has to add to the heat produced by the generator which is a real problem for the Revmaster stator.  I am hoping that a switching type regulator will keep the stator cooler.

 

 Paul

 

 

 

 

 Read this topic online here:

 

 http://forums.matronics.com/viewtopic.php?p=507184#507184

 

 

 

 

 

 

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Paul Eckenroth

Joined: 29 Jun 2010
Posts: 14

Posted: Mon Jun 13, 2022 1:35 pm Post subject: Re: Switched voltage generator

I am aware of the Lithium battery low resistance situation but also believe that the regulator must add to the problem.  If, as I believe, the shunt regulator shunts to ground when the charge of the battery is satisfied then that action should be as much or more of a problem than the low resistance battery.  Thus my search for a non shunt regulator that can handle the rigors of flight.  If you know of special regulators that are made for this purpose please send me details.  Also if my understanding of the shunt regulator is faulty, please correct me.  Thanks.



Paul

user9253

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

Posted: Mon Jun 13, 2022 5:03 pm Post subject: Re: Switched voltage generator

My John Deere regulator is a switching type.  The outside air temperature was 80° F when I flew Saturday, 3 days ago.

There is a thermocouple on my voltage regulator.  Its temperature is displayed on the Dynon D-180.

The highest voltage regulator temperature Saturday was 151 °F.

_________________
Joe Gores

Paul Eckenroth

Joined: 29 Jun 2010
Posts: 14

Posted: Tue Jun 14, 2022 4:42 am Post subject: Re: Switched voltage generator

I believe I have the John Deere regulator in the workshop.  How do I confirm what type of regulator it is.  Is there a simple way to test it.  Thanks



Paul

user9253

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

Posted: Tue Jun 14, 2022 5:57 pm Post subject: Re: Switched voltage generator

Buy a type "J" thermocouple and attach it to the voltage regulator.

https://www.omega.com/en-us/temperature-measurement/temperature-surface-sensors/wt/p/WTJ-6-60

I attached a thermocouple using a regulator mounting bolt.  

Monitor the thermocouple temperature somehow.  I connected mine to the Dynon D-180 in my plane.

Go flying and monitor the regulator temperature with a heavy load, then a medium load, and then a very light load.

If the temperature goes up with the load, the regulator is a switching type.

_________________
Joe Gores

nuckolls.bob(at)aeroelect
Guest

Posted: Sun Jun 19, 2022 5:56 am Post subject: Switched voltage generator

At 08:57 PM 6/14/2022, you wrote:

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



 Buy a type "J" thermocouple and attach it to the voltage regulator.

  https://www.omega.com/en-us/temperature-measurement/temperature-surface-sensors/wt/p/WTJ-6-60 

 I attached a thermocouple using a regulator mounting bolt.  

 Monitor the thermocouple temperature somehow.  I connected mine to the Dynon D-180 in my plane.

 Go flying and monitor the regulator temperature with a heavy load, then a medium load, and then a very light load.

 If the temperature goes up with the load, the regulator is a switching type. 	


   A cogent observation.



   I would like to suggest a refinement of terms for the

   rectifier/regulators common to permanent magnet

   alternator installations. Early in this thread, a

   writer expressed some confusion arising from his

   search for sources on 'switching regulators' . . .

   seems those little bits of plastic with a few connections

   coming out of them were not applicable to managing

   the energy available from an PM alternator . . .



   He's right.  In the broader world of electron herding,

   SWITCHMODE regulators describe a class of devices common

   to electronic energy management devices found in virtually

   all consumer products. Things like the little 'wall warts'

   that quick-charge our mobile phones up to sine-wave, DC to

   AC inverters that might manage thousand of watts . . .

   and everything in between. They are the core technology

   of step-up, step-down converters and power suplies in our

   computers with 'switching' frequencies on the order

   of tens of thousands of Hz and higher.



   In the PM alternator world, the smallest devices first

   showed up in mini-bikes and garden tractors over 40

   years ago. The simplest regulators took advantage of

   a common design for small alternators that rendered

   them impervious to damage to to 'dead shorting' of the

   output windings. So the easiest regulator designs

   would literally short out or SHUNT excess energy

   when a battery was fully charged.



   This produces a situation where the alternator is

   essentially loaded to full capacity 100% of the time

   with the regulator preventing battery overcharge

   (or bus over voltage) by turning unneeded energy

   into heat . . . both the alternator and regulator

   needed design features that tolerated what in

   other situations might be considered severe or

   even catastrophic overload.



   As magnet technology improved and electrical

   demands on small machines grew, larger alternators

   were developed . . . many configured with 3-phase

   windings. Tossing off excess energy with a SHUNT

   style rectifier/regulator became rather undesirable

   from an efficiency and performance standpoint.



   SERIES type regulators were crafted that controlled

   excess energy by disconnecting the alternator from

   the system during some portion of the AC output

   waveform. This produced a situation where as demands

   for engine driven energy went down (battery charged,

   system load minimal), alternator and regulator

   temperatures went DOWN.



   Obviously, the generation of heat is directly

   related to efficiency so the optimal design

   works to minimize waste heat in both machine

   and electronics.



   Getting back to the core premise of this thread,

   the Revmaster engine has a profound design flaw

   in the alternator stator which promotes the

   burning of windings.

   



 

   Bob . . .



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

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

   out of that stuff?"

nuckolls.bob(at)aeroelect
Guest

Posted: Tue Jun 28, 2022 6:07 pm Post subject: Switched voltage generator

At 07:12 PM 6/12/2022, you wrote:

  	  Quote: 	
		  --> AeroElectric-List message posted by: "Paul Eckenroth" <jeckenroth(at)nbn.net>



 I need suggestion for a switched Voltage and current regulator to be used with a PM generator.  I have a Revmaster engine with a burned stator which I am replacing.  The stock voltage generator is a shunt type.  I see plenty of switching voltage regulators on line but they all look like they were designed for use on a printed circuit board, not for the firewall of a airplane.  Thanks



 Paul 	




   It's not possible to tell whose rectifier/regulator

   is of the shunt/series type without having access

   to the schematic. However, modern 'shunt' regulators

   (more often called FET regulators) are not as

   abusive to the PM alternator as the SCR shunt devices

   circa 1965.



   The Revmaster alternator stator has some

   serious design problems that make it prone

   failure of the winding.



   Hence, type of battery and style of rectifier/

   regulator may have some effect on service life

   of the stator windings . . . but they are not

   root cause for the failures.



 

 

   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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