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solid state relays

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jbr79r(at)yahoo.com
Guest

Posted: Sat Feb 12, 2011 10:51 pm Post subject: solid state relays

Hi Bob

What is your opinion of these relays as replacements for the mechanical relays we have been using?

Jim Robinson

www.newark.com/crydom+relay



 [quote][b]

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nuckolls.bob(at)aeroelect
Guest

Posted: Sun Feb 13, 2011 7:30 am Post subject: solid state relays

At 12:45 AM 2/13/2011, you wrote:

  	  Quote: 	
		  Hi Bob

 What is your opinion of these relays as replacements for the mechanical relays we have been using?

 Jim Robinson

 	


   Lamar (and perhaps others) have brought production

   solid state contactors to the market that are

   BI-DIRECTIONAL. I.e, the can both load and charge

   a battery making them suitable for battery

   contactors as opposed to rudimentary control

   devices (relays).



 [img]cid:7.1.0.9.0.20110213091942.01f109a0(at)aeroelectric.com.0[/img] 



 

   I have no reason to believe they do not perform

   as advertised.  Lamar was going to send me one

   to play with but I think that offer fell into

   a crack. In any case, assuming they DO perform

   as advertised, what are your design goals that

   might drive a decision to substitute this product

   into your airplane? Assuming further that your

   airplane is architectured to offer a plan-b

   for contactor failure, will this substitution offer

   a demonstrable reduction in cost of ownership?

   

   Bob . . .

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berkut13(at)berkut13.com
Guest

Posted: Sun Feb 13, 2011 9:36 am Post subject: solid state relays

Jim,

 I’ve used them in several application in our projects.  They performed  well (better than the mechanicals) in high stress applications like running the  hydraulic gear pump that is prone to fast on/off re-press cycles.  In fact,  I liked them so much I replaced my old heavy clunkers with the lighter  Crydoms.

  

 http://www.berkut13.com/berkut50.htm#SSR

  

 Don’t forget the “freewheel” diodes on motor loads.  The schematics  are in the data sheet.

  

 James Redmon

 Berkut/Race 13

  

    

  From: James Robinson (jbr79r(at)yahoo.com) 

 Sent: Saturday, February 12, 2011 10:45 PM

 To: aeroelectric-list(at)matronics.com (aeroelectric-list(at)matronics.com)  

 Subject: solid state relays

  



   Hi  Bob

What is your opinion of these relays as replacements for the mechanical  relays we have been using?

Jim Robinson

www.newark.com/crydom+relay



[quote] [b]

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JLuckey(at)pacbell.net
Guest

Posted: Sun Feb 13, 2011 11:49 am Post subject: solid state relays

The Crydom units seem pretty cool & for certain applications they are ideal but.. (putting on my devil’s advocate hat..)  

   

There are a couple of things to consider:  

     They      seem a little pricey – Digikey lists them for ~$118 each. (the      equivalent ‘can-type’ contactor is ~$30)  
If      you need SPST or DPST contacts you are SOL  
In      many applications, you need to surround them w/ protection diodes and/or      MOVs or whatever (more components to mount & connect & possibly      fail…)   

   

An example: (I’m just making this up;)  

Let’s say you want to run a PM motor forward & backward.  You can create an H bridge circuit w/ 2 mechanical SPDT relays pretty easily & for less than $50.   

   

To accomplish the same thing w/ the Crydoms you’ll need 4 Crydom units.  (That’s ~$500.)  And some clever circuitry to prevent the wrong pairs of relays from energizing at the same time.  (so you don’t release their [expensive] magic smoke)  

   

With the versatility of a properly-chosen good-old mechanical relay, it is often possible to use the same relay in many different circuits aboard you plane.  That can mean reduced part# count.  That’s simpler, easier to keep spares, allows emergency substitution, etc.  

   

Don’t get me wrong, I’m all over semiconductors when they make circuitry simpler, better, cheaper, etc.  But until the price point comes down quite a bit, it’s hard to beat good-old mechanical relays.  

   

   

   

-Jeff  

   

   

         

  

From: owner-aeroelectric-list-server(at)matronics.com [mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of berkut13(at)berkut13.com

 Sent: Sunday, February 13, 2011 09:28

 To: aeroelectric-list(at)matronics.com

 Subject: Re: AeroElectric-List: solid state relays  

  

         

   

    

Jim,  

    

I’ve used them in several application in our projects.  They performed well (better than the mechanicals) in high stress applications like running the hydraulic gear pump that is prone to fast on/off re-press cycles.  In fact, I liked them so much I replaced my old heavy clunkers with the lighter Crydoms.  

    

   

    

http://www.berkut13.com/berkut50.htm#SSR  

    

   

    

Don’t forget the “freewheel” diodes on motor loads.  The schematics are in the data sheet.  

    

   

    

James Redmon  

    

Berkut/Race 13  

    

   

        

   

      

From: James Robinson (jbr79r(at)yahoo.com)   

    

Sent: Saturday, February 12, 2011 10:45 PM  

    

To: aeroelectric-list(at)matronics.com (aeroelectric-list(at)matronics.com)   

    

Subject: solid state relays  

  

  

    

   

  

        

Hi Bob

 [i]What is your opinion of these relays as replacements for the mechanical relays we have been using?

 Jim Robinson

 

 

 www.newark.com/crydom+relay[/i]  

  

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berkut13(at)berkut13.com
Guest

Posted: Sun Feb 13, 2011 12:40 pm Post subject: solid state relays

What you wrote is all true...however....

  

 At work, we were using the Leech Mill-Spec, inert gas filled, high-end  relays...they were still failing during circuit break due to arcing.    2 Crydoms were cheaper than 4 of these for an H-bridge.  Admittedly, the  switch to SSRs was done in the interest of a quick fix to get the vehicles back  in air...but it did solve the problem.  Putting the mechanicals in the  H-bridge config was not a guarantee that the failures would not re-occur and we  didn’t want to pile on arc snubbers.

  

 Personally, I had more than reliability reasons for the change – mainly  weight, environmental concerns, and ease of retrofit.

 -James

  

    

  From: Jeff Luckey (JLuckey(at)pacbell.net) 

 Sent: Sunday, February 13, 2011 11:44 AM

 To: aeroelectric-list(at)matronics.com (aeroelectric-list(at)matronics.com)  

 Subject: RE: solid state relays

  



   

The Crydom units seem  pretty cool & for certain applications they are ideal but.. (putting on my  devil’s advocate hat..) 

  

There are a couple of  things to consider: 

     They seem a little pricey –    Digikey lists them for ~$118 each. (the equivalent ‘can-type’ contactor is    ~$30)    
If you need SPST or DPST contacts    you are SOL    
In many applications, you need to    surround them w/ protection diodes and/or MOVs or whatever (more components to    mount & connect & possibly fail…)  

  

An example: (I’m just  making this up;) 

Let’s say you want to  run a PM motor forward & backward.  You can create an H bridge circuit  w/ 2 mechanical SPDT relays pretty easily & for less than $50.   

  

To accomplish the same  thing w/ the Crydoms you’ll need 4 Crydom units.  (That’s ~$500.)  And  some clever circuitry to prevent the wrong pairs of relays from energizing at  the same time.  (so you don’t release their [expensive] magic  smoke) 

  

With the versatility of  a properly-chosen good-old mechanical relay, it is often possible to use the  same relay in many different circuits aboard you plane.  That can mean  reduced part# count.  That’s simpler, easier to keep spares, allows  emergency substitution, etc. 

  

Don’t get me wrong, I’m  all over semiconductors when they make circuitry simpler, better, cheaper,  etc.  But until the price point comes down quite a bit, it’s hard to beat  good-old mechanical relays. 

  

  

  

-Jeff 

  

  

     

 

From:  owner-aeroelectric-list-server(at)matronics.com  [mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of  berkut13(at)berkut13.com

Sent: Sunday, February 13, 2011  09:28

To: aeroelectric-list(at)matronics.com

Subject: Re: solid state  relays

 

     

 

  

Jim,

  

I’ve used them in  several application in our projects.  They performed well (better than the  mechanicals) in high stress applications like running the hydraulic gear pump  that is prone to fast on/off re-press cycles.  In fact, I liked them so  much I replaced my old heavy clunkers with the lighter  Crydoms.

  

 

  

http://www.berkut13.com/berkut50.htm#SSR

  

 

  

Don’t forget the  “freewheel” diodes on motor loads.  The schematics are in the data  sheet.

  

 

  

James  Redmon

  

Berkut/Race  13

  

 

    

 

   [quote][b]

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ainut(at)knology.net
Guest

Posted: Sun Feb 13, 2011 12:58 pm Post subject: solid state relays

What concerns are there from "freewheel" diodes?



Thanks,

David M.

berkut13(at)berkut13.com wrote:

 	  Quote: 	
		   Jim,

 I’ve used them in several application in our projects.  They performed 

 well (better than the mechanicals) in high stress applications like 

 running the hydraulic gear pump that is prone to fast on/off re-press 

 cycles.  In fact, I liked them so much I replaced my old heavy 

 clunkers with the lighter Crydoms.

 http://www.berkut13.com/berkut50.htm#SSR

 Don’t forget the “freewheel” diodes on motor loads.  The schematics 

 are in the data sheet.

 James Redmon

 Berkut/Race 13

 *From:* James Robinson <mailto:jbr79r(at)yahoo.com>

 *Sent:* Saturday, February 12, 2011 10:45 PM

 *To:* aeroelectric-list(at)matronics.com 

 <mailto:aeroelectric-list(at)matronics.com>

 *Subject:* solid state relays

 Hi Bob

 What is your opinion of these relays as replacements for the 

 mechanical relays we have been using?

 Jim Robinson

 www.newark.com/ <http://www.newark.com/>*crydom+relay*

   

 *

 *


	


-- 

If you're an American, just say NO to the Obamanation, to socialism, and get rid of Soros.

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berkut13(at)berkut13.com
Guest

Posted: Sun Feb 13, 2011 5:04 pm Post subject: solid state relays

 	  Quote: 	
		  From diodes?  Point them the correct direction.


	


 	  Quote: 	
		  From the motor...there is a reverse break down current generated when the 

power to the motor is cut off.  That reverse flow of current is not good for 
	


the MOSFET inside the SSR.  The diodes channel that current back to the 

robust windings of the motor (freewheeling) instead of making the SSR 

convert it to heat.



Fun stuff, no?



-James



--

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jbr79r(at)yahoo.com
Guest

Posted: Sun Feb 13, 2011 6:04 pm Post subject: solid state relays

I currently have one com antenna in the vertical of my Glasair.  I only have one comm radio SL30.  I have been thinking of adding a second com radio, possibly a 

 Garmin 430.  Will I need an audio panel also?  Can both radios share the one antenna?  Or what would be the best arrangement for the setup?

Jim



James Robinson

Glasair lll  N79R

Spanish Fork UT  U77



 



 

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