Matronics Email Lists :: View topic

Matronics Email Lists
Web Forum Interface to the Matronics Email Lists

Get Email Distribution Too! FAQ Search Memberlist Usergroups Register

Profile Log in to check your private messages Log in

Battery solenoids

Matronics Email Lists Forum Index -> Europa-List

View previous topic :: View next topic

Author Message

paul.mitchell2(at)homecal
Guest

Posted: Fri Jan 27, 2006 12:28 am Post subject: Battery solenoids

Can anyone tell me how hot I can expect the battery isolation solenoid case to be after being "on" on the ground and carrying 2 amps for an hour . Mine is really warm to the point of being too hot to hold for more than 10 seconds. Do you think it is faulty

Paul Mitchell

rholder(at)avnet.co.uk
Guest

Posted: Fri Jan 27, 2006 1:32 am Post subject: Battery solenoids

 	  Quote: 	
		   Can anyone tell me how hot I can expect the battery

 isolation solenoid case to be after being "on" on the

 ground and carrying 2 amps for an hour . Mine is really

 warm to the point of being too hot to hold for more

 than 10 seconds. Do you think it is faulty Paul

 Mitchell


	


It should not be carrying 2 amps. With the Rotax you only

have 19 amps to play with. If your solenoid is designed to

actually use 2 amps it is unsuitable.



I used a "rally/race car" master switch (red in colour) as

the battery cut off in mine. It uses no current to

activate itself !



Then if you want a master switch operated solenoid for the

non-starter battery current then a much smaller one can be

used - with a max switching capacity of about 25 - 30

amps. I have seen such which only use 0.1 amp for their coils.



Richard

paul.mitchell2(at)homecal
Guest

Posted: Fri Jan 27, 2006 2:51 am Post subject: Battery solenoids

Richard,

I believe it is the coil current that is generating the heat, not the load. 

Think it must be  faulty. Any idea where I can get one of these master 

switch operated solenoids with the 0.1 amp coil load.

Paul

---

Mark Burton

Joined: 10 Jan 2006
Posts: 74

Posted: Fri Jan 27, 2006 3:48 am Post subject: Re: Battery solenoids

Considering the principle of how the Rotax "regulator" operates (i.e. by shorting out the generator coils when the output voltage exceeds a limit), it is a possibility that having a permanent load of 1 or 2 amps is actually "kinder" to the regulator because it helps stop the load dropping to the point where the regulator actually starts "regulating". Maybe it's better to warm up the solenoid coil than warm the regulator innards.



Obviously, if you can't afford to loose 2 amps to the solenoid, don't use it.

hurstkr(at)growzone.com.a
Guest

Posted: Fri Jan 27, 2006 4:25 am Post subject: Battery solenoids

 	  Quote: 	
		   I believe it is the coil current that is generating the heat, not the 

 load.

 Think it must be  faulty.


	


Paul,



I doubt your contactor is faulty.

If it is one of the metal can types, it is quite normal for them to get 

quite hot or too hot to touch.



Regards

Kingsley

Gilles.Thesee(at)ac-greno
Guest

Posted: Fri Jan 27, 2006 5:51 am Post subject: Battery solenoids

Mark Burton a crit :



 	  Quote: 	
		  



Considering the principle of how the Rotax "regulator" operates (i.e. by shorting out the generator coils when the output voltage exceeds a limit), it is a possibility that having a permanent load of 1 or 2 amps is actually "kinder" to the regulator because it helps stop the load dropping to the point where the regulator actually starts "regulating". Maybe it's better to warm up the solenoid coil than warm the regulator innards.



  




	


Mark and all,



For what it's worth, the Rotax regulator doesn't work the way you state. 

Actually, the more amps it delivers, the more it warms up. Hence the 

problems encountered with too many amp-hungry goodies. In my opinion, 

drawing 19 amps is very optimistic in anything but the coldest outside 

temperatures. Something around 12 amps seems more conservative. Of 

course, 1-2 amps won't do any harm, be the amp budget is so limited with 

the continuous load of the electric fuel pump on the 914.



In the future, I'll publish a summary of the tests we conducted on the 

Rotax alternator/regulator, with pictures, regulator schematics and 

thermal investigations.



Regards,

Gilles Thesee

Grenoble, France

http://contrails.free.fr

Mark Burton

Joined: 10 Jan 2006
Posts: 74

Posted: Fri Jan 27, 2006 7:52 am Post subject: Re: Battery solenoids

Is the Rotax rectifier regulator not a shunt regulator then? There's quite a lot of references on the web to it being of that type.

Gilles.Thesee(at)ac-greno
Guest

Posted: Fri Jan 27, 2006 8:16 am Post subject: Battery solenoids

Mark Burton a crit :



 	  Quote: 	
		  



Is the Rotax rectifier regulator not a shunt regulator then? There's quite a lot of references on the web to it being of that type.



  




	


I'm afraid it is not.

I dismantled several of them, made a diagram,  and we bench tested one 

with a Rotax alternator rotor and stator. We also made a comparison with 

a Schicke regulator.

My buddy's students made a study of the thermal behaviour of the 

Rotax/Ducati and the Schicke.

When I have some time, I'll publish a complete summary on the topic.



Regards,

Gilles Thesee

Grenoble, France

http://contrails.free.fr

hdwysong(at)gmail.com
Guest

Posted: Fri Jan 27, 2006 8:34 am Post subject: Battery solenoids

.. and then we'll all be eagerly awaiting the day when you and Herr Schicke

set up an eBay store so we (across the pond) can get our hands this improved

regulator/rectifier!  



D



----------------

On 1/27/06, Gilles Thesee <Gilles.Thesee(at)ac-grenoble.fr> wrote:

 	  Quote: 	
		  

 <snip>  When I have some time, I'll publish a complete summary on the

 topic.



 Regards,

 Gilles Thesee

 Grenoble, France

 http://contrails.free.fr

n3eu(at)comcast.net
Guest

Posted: Fri Jan 27, 2006 11:30 am Post subject: Battery solenoids

An aircraft battery relay draws 1A or a bit less,

dissipating about 15W, so a device that big shouldn't get

hot.  A 50W resistor is about the size of our little finger.



I tried a latching relay, which draw zero, but takes a brief

voltage to flip-flop 'em with a mere pushbutton switch.

Found out two things.  One was the spec sheet was deceptive

about its power handling ability.  The contact resistance

was too high, and it would cause about one volt drop when

the starter was engaged.  We don't need that for best

starter RPM, so watch any substitute, non-aircraft-type

relay.



A latching relay will not fail safe though.  If in an

emergency, like where a large current develops which doesn't

pop a breaker, we may just have to wait for things to melt

and hope a fire doesn't start!



Reg,

Fred F.

n3eu(at)comcast.net
Guest

Posted: Fri Jan 27, 2006 11:30 am Post subject: Battery solenoids

Mark Burton wrote:

 	  Quote: 	
		  

 Is the Rotax rectifier regulator not a shunt regulator

then?
	


 	  Quote: 	
		   There's quite a lot of references on the web to it being

of that type.
	


 	  Quote: 	
		  


	


Circuit schematic suggests to me it is a shunt, bit not of

classic variety.  It appears it has to dissipate heat either

no-load or high-load, for different reasons, but high-load

looks worse to me.  Four semicon devices maybe about near

their rating in the watts department.  Shouldn't design 'em

that way.



Reg,

Fred F.

Gilles.Thesee(at)ac-greno
Guest

Posted: Fri Jan 27, 2006 2:24 pm Post subject: Battery solenoids

 	  Quote: 	
		  Circuit schematic suggests to me it is a shunt, bit not of

classic variety.  It appears it has to dissipate heat either

no-load or high-load, for different reasons, but high-load

looks worse to me.

  



Fred and all,
	




According to measurements we took two years ago, it appears the 

Rotax/Ducati heat dissipation is proportional to the output. As you 

said, a shunt type regulator would dissipate much heat whatever the load.

In order to help clarify matters, I hurriedly wrote this little page :



http://contrails.free.fr/elec_ducati_en.php



Further info in the future, when I sort out my previous documents and 

translate them.

FWIW,

Regards,

Gilles Thesee

Grenoble, France

http://contrails.free.fr

n3eu(at)comcast.net
Guest

Posted: Fri Jan 27, 2006 7:36 pm Post subject: Battery solenoids

Gilles Thesee wrote:

 	  Quote: 	
		  

 According to measurements we took two years ago, it

appears the
	


 	  Quote: 	
		   Rotax/Ducati heat dissipation is proportional to the

output. As you
	


 	  Quote: 	
		   said, a shunt type regulator would dissipate much heat

whatever the load.
	




If the TO-220 case semiconductor pair are SCRs, then in that

circuit "abuse" would be proportional to load.  It still has

to shunt in proprtion to lighter load, but perhaps with less

abuse.  Maybe phase lag at the high freq of the many coils?

Anyway, it's not a series regulator, but appears to

dissipate heat like one, proprtional to load.  So, if all

true, it doesn't matter what it's called.  It's

regulator....which can get hot.  But that's not important

right now.     I mounted mine inside the cabin to help

matters.  Nice work on your site, BTW.



Reg,

Fred F.

Mark Burton

Joined: 10 Jan 2006
Posts: 74

Posted: Sat Jan 28, 2006 2:28 am Post subject: Rotax regulator innards (was Battery solenoids)

Fred kindly supplied me with a copy of the schematic.



It looks like a shunt regulator to me.



It makes more sense if the two transistors marked tp154e are actually N channel MOSFETs with body diodes incorporated (or do some SCRs have a reverse conduction mode?) Otherwise, the circuit is missing the two diodes needed to connect the -ve side of the generator coil to ground. If the above is true, the dissipation at high load curents is simply the voltage drop across the body diodes + the voltage drop across the other two diodes (mr2510) times the load current.



Google doesn't return any useful hits for tp154e.



Bit worried about the two resistors marked 47 because as soon as the input goes +ve the transistor/SCR/MOSFET would turn on and immediately short out the coil. Can't believe that's right!



If the above is true, my original point about the external load of the battery solenoid reducing the dissipation in the regulator is also true in the situation where the total current drawn from the regulator is sufficiently low to allow the voltage to rise to the point where the shunt transistors turn on.

rholder(at)avnet.co.uk
Guest

Posted: Sat Jan 28, 2006 3:16 am Post subject: Battery solenoids

 	  Quote: 	
		   Richard,


	


 	  Quote: 	
		   I believe it is the coil current that is generating the

 heat, not the load. Think it must be  faulty. Any idea

 where I can get one of these master switch operated

 solenoids with the 0.1 amp coil load.


	


 	  Quote: 	
		   Paul


	


Paul



If you want a relay to operate the battery connection to

the starter you will need a big relay, and a manually

operated "big red switch" from a rally car is better.



For a relay to be operateded by your master switch

(without taking the starter load) RS have them.



308-0611 at 2.50



for SPNO (Normally open) and a switching current max of 40

amps.



Coil power 1.6 watts = 0.13 amps.



Page 1-1553 in their latest catalogue or at a store near you !



HTH



Richard

paul.mitchell2(at)homecal
Guest

Posted: Sat Jan 28, 2006 3:39 am Post subject: Battery solenoids

Richard,

Many thanks, As soon as I sent mine to you, I got yours.

I have ordered one from RS.

Paul

---

Display posts from previous:

	Matronics Email Lists Forum Index -> Europa-List	All times are GMT - 8 Hours
Page 1 of 1

Jump to:

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum