Matronics Email Lists :: View topic - Relay for OV Protection

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

Relay for OV Protection

Matronics Email Lists Forum Index -> AeroElectric-List

View previous topic :: View next topic

Author Message

teblejw

Joined: 19 Nov 2013
Posts: 14

Posted: Tue Feb 04, 2014 12:13 pm Post subject: Relay for OV Protection

In modifying Z-07 or Z-19 for my Viking engine, I will add over-voltage protection for the Viking-supplied, internally regulated, 40A alternator by ND.  Based in part on Bob's demonstration in the literature of a type 70 contactor opening under simulated o.v. conditions, I'd started to plan on such a relay/contactor instead of spending over $200 on an EV200 or similar.  But since the  relay is not in the starting loop, could I use a stout auto relay instead?  I recently became aware of the Picker 7150 (now sold by Waytek) that has ratings of 75V switching voltage and 150A for continuous load and breaking.  It has 3/8" quick tabs for the load, but connectors for #8 wire are available from Digikey.  Advantages would be weight (2.1 oz.) and electrical draw (2.9W).  Are there potential problems?  Btw, I'm not concerned with it surviving an o.v. event, since it would cost $20 or so to replace.  Thanks in advance for any feedback.



Tom



Sent from my iPad

- The Matronics AeroElectric-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?AeroElectric-List

nuckolls.bob(at)aeroelect
Guest

Posted: Tue Feb 04, 2014 1:43 pm Post subject: Relay for OV Protection

At 02:12 PM 2/4/2014, you wrote:


<tomblejwas(at)yahoo.com>



In modifying Z-07 or Z-19 for my Viking engine, I will add 

over-voltage protection for the Viking-supplied, internally 

regulated, 40A alternator by ND.  Based in part on Bob's 

demonstration in the literature of a type 70 contactor opening under 

simulated o.v. conditions, I'd started to plan on such a 

relay/contactor instead of spending over $200 on an EV200 or 

similar.  But since the  relay is not in the starting loop, could I 

use a stout auto relay instead?  I recently became aware of the 

Picker 7150 (now sold by Waytek) that has ratings of 75V switching 

voltage and 150A for continuous load and breaking.  It has 3/8" quick 

tabs for the load, but connectors for #8 wire are available from 

Digikey.  Advantages would be weight (2.1 oz.) and electrical draw 

(2.9W).  Are there potential problems?  Btw, I'm not concerned with 

it surviving an o.v. event, since it would cost $20 or so to 

replace.  Thanks in advance for any feedback.



Tom



    Give it a try!  The ratings are good.



http://tinyurl.com/kwlvfj2



    I note that they come with built in coil

    suppression that appears to be a plain vanilla

    diode.



    Your "high-risk" features are centered more on

    the connectors and crimps than on the relay.



    Of all the S700-3 switches 'smoked' by strobe systems,

    I don't think we've seen any evidence of contact's

    ill suited to the task. We've seen terminals overheat

    and do the precipitous slide to smoke and fire, also

    compression joints across plastic housings (tabs

    held by rivets) and even some 'teeter totters' that

    annealed and deformed . . . but the contacts looked

    fine.



    What we're learning here is the value of gas-tight

    integrity for made up joints . . . they appear

    far more vulnerable to abusive electron flows than

    the actual controlling contacts.



    With 3/8" fast-on tabs, you might consider drilling

    them for #6 screw and using ring terminals to attach.

    I think I'd go for a soldered-on non insulated

    ring terminal too. With due diligence to your made

    up joints, odds for success are quite good.



    Now for the caveats . . . this is a plastic enclosure

    and a runaway IR alternator ALWAYS goes into self

    destruct by putting something on the order of 200 volts

    on its own field winding - and nearly as much on the

    b-lead disconnect relay. The only concern I have is

    for the possibility of internal-eternal fire getting

    outside the housing . . . this was not a concern with

    the metal housed Model 70.



   Bob . . .

- The Matronics AeroElectric-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?AeroElectric-List

teblejw

Joined: 19 Nov 2013
Posts: 14

Posted: Tue Feb 04, 2014 6:51 pm Post subject: Relay for OV Protection

Thanks Bob.  I particularly appreciate the caveat.  If the runaway can really get to 200V in 5 ms, then I will have a hard time evaluating the potential risk. 



Tom



Sent from my iPad



 	  Quote: 	
		   On Feb 4, 2014, at 2:42 PM, "Robert L. Nuckolls, III" <nuckolls.bob(at)aeroelectric.com> wrote:

 

 

 

 At 02:12 PM 2/4/2014, you wrote:

 

 

 In modifying Z-07 or Z-19 for my Viking engine, I will add over-voltage protection for the Viking-supplied, internally regulated, 40A alternator by ND.  Based in part on Bob's demonstration in the literature of a type 70 contactor opening under simulated o.v. conditions, I'd started to plan on such a relay/contactor instead of spending over $200 on an EV200 or similar.  But since the  relay is not in the starting loop, could I use a stout auto relay instead?  I recently became aware of the Picker 7150 (now sold by Waytek) that has ratings of 75V switching voltage and 150A for continuous load and breaking.  It has 3/8" quick tabs for the load, but connectors for #8 wire are available from Digikey.  Advantages would be weight (2.1 oz.) and electrical draw (2.9W).  Are there potential problems?  Btw, I'm not concerned with it surviving an o.v. event, since it would cost $20 or so to replace.  Thanks in advance for any feedback.

 

 Tom

 

   Give it a try!  The ratings are good.

 

 http://tinyurl.com/kwlvfj2

 

   I note that they come with built in coil

   suppression that appears to be a plain vanilla

   diode.

 

   Your "high-risk" features are centered more on

   the connectors and crimps than on the relay.

 

   Of all the S700-3 switches 'smoked' by strobe systems,

   I don't think we've seen any evidence of contact's

   ill suited to the task. We've seen terminals overheat

   and do the precipitous slide to smoke and fire, also

   compression joints across plastic housings (tabs

   held by rivets) and even some 'teeter totters' that

   annealed and deformed . . . but the contacts looked

   fine.

 

   What we're learning here is the value of gas-tight

   integrity for made up joints . . . they appear

   far more vulnerable to abusive electron flows than

   the actual controlling contacts.

 

   With 3/8" fast-on tabs, you might consider drilling

   them for #6 screw and using ring terminals to attach.

   I think I'd go for a soldered-on non insulated

   ring terminal too. With due diligence to your made

   up joints, odds for success are quite good.

 

   Now for the caveats . . . this is a plastic enclosure

   and a runaway IR alternator ALWAYS goes into self

   destruct by putting something on the order of 200 volts

   on its own field winding - and nearly as much on the

   b-lead disconnect relay. The only concern I have is

   for the possibility of internal-eternal fire getting

   outside the housing . . . this was not a concern with

   the metal housed Model 70.

 

 

 

  Bob . . .

- The Matronics AeroElectric-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?AeroElectric-List

Display posts from previous:

	Matronics Email Lists Forum Index -> AeroElectric-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