SSR, Heatsink and Thermal Grease Question

[thekraken]

How did you determine that the base plate (which is also intended to be a heat spreader) is steel? Is it magnetic? Steel has lousy thermal conductivity, so is a very poor choice to use as a heat spreader. I worked for over thirty years in electronic component packaging, and don't remember any instances of steel used for a heat spreader (but we didn't build SSR's.)

Brew on

I'm sorry, I just spoke out of hand, my point was really that it wasn't epoxy. It's most likely aluminum isn't it? In that case it should be easy enough to sand flat.

 

[doug293cz]

I'm sorry, I just spoke out of hand, my point was really that it wasn't epoxy. It's most likely aluminum isn't it? In that case it should be easy enough to sand flat.

Could be a number of things, aluminum being one of them. We used nickel plated copper for out IC packages. Other possibilities are Cu/W or Cu/Mo composites. Here's a link to one supplier of heatspreaders for electronic packages.

 

[augiedoggy]

It is a non magnetic aluminum or alloy mix... I just checked mine..

 

[IslandLizard]

I must say that surface looks very crude. Almost as if they're still unfinished, pulled from the assembly line. Maybe it doesn't matter. I'd mount one and try it at low loads keeping a close eye on the temps while ramping up slowly. If they work at 5A they're likely to work at higher loads, with an adequate heat sink and junction.

If they didn't work don't you think the feedback would reflect that?

Given the price the OP paid, which is great by any standard, and the time it took to discuss this these could have been trued and mirror polished by now.

I always lap and polish heat sinks for CPUs I install. They maybe flat, but the surface is typically too coarse for my taste.

 

[augiedoggy]

I must say that surface looks very crude. Almost as if they're still unfinished, pulled from the assembly line. Maybe it doesn't matter. I'd mount one and try it at low loads keeping a close eye on the temps while ramping up slowly. If they work at 5A they're likely to work at higher loads, with an adequate heat sink and junction.

If they didn't work don't you think the feedback would reflect that?

Given the price the OP paid, which is great by any standard, and the time it took to discuss this these could have been trued and mirror polished by now.

I always lap and polish heat sinks for CPUs I install. They maybe flat, but the surface is typically too coarse for my taste.

It should be noted that while polishing and laping certainly wont hurt and may have some incremental improvement.... Its completely not needed nor practical as long as the components are sized correctly...
I have been building pc's for 15 years and have never needed to do this nor have I needed to and the base of an ssr provides enough surface area to not need this, There are members here that dont even use heat sinks... some use the painted metal enclosure as the heatsink others sandwich the metal enclosure between the heatsink and ssr...

 

[thekraken]

Fixed it.

It's now flat. I went up to 1000 grit for s**** and giggles since I had it.

 

[thekraken]

FYI - I had been emailing Teledyne about this issue. He said that clones or fakes for this product are fairly rare, from the pictures I sent him he said they appear genuine.

 

[aaronlalonde]

are these wired up as L1-T1 as one leg and L2-T2 as another leg?

also do i need to put each leg of the 220v side on the relay and does the auber/mypin PID output for each leg or are the PID output wired parallel to the 4 pin wafer connector?

 

[augiedoggy]

are these wired up as L1-T1 as one leg and L2-T2 as another leg?

also do i need to put each leg of the 220v side on the relay and does the auber/mypin PID output for each leg or are the PID output wired parallel to the 4 pin wafer connector?

Its a switch... in a normal single ssr only one leg goes through it... example l2 in and l2 out... the other two terminals are for the 24v (or 12-32v?) switching signal from the pid...
if you want to use this dual ssr to control both legs you can wire it the way you said by wiring the control wires in parallel and using each leg of the ssr for a different leg. I dont remember but I think you cant use jumpers due to the layout of the pins but I may be wrong.

 

[Bobby_M]

Its a switch... in a normal single ssr only one leg goes through it... example l2 in and l2 out... the other two terminals are for the 24v (or 12-32v?) switching signal from the pid...
if you want to use this dual ssr to control both legs you can wire it the way you said by wiring the control wires in parallel and using each leg of the ssr for a different leg. I dont remember but I think you cant use jumpers due to the layout of the pins but I may be wrong.

http://www.teledynerelays.com/pdf/industrial/sd.pdf

 

[rak44]

I have three of these Teledyne SD24R50 relays. All three of them have a slight curvature to the bottom mounting surface such that very little of it would make contact with a flat heat sink. This gap could be filled with relatively large amount of thermal grease.

Are these okay to use with so much grease? Is this gap too big?

I'll need to dissipate about 24 watts, these are 50A relays I should only draw about <15.

Maybe I would fill it up with some heat conductor. have one layer of some good thermal grease, then piece of aluminium and other layer of thermal grease on the top. Keep in mind that you cant have any empty space there. I have no idea if it would work but it is worth a try. Btw what thermal grease are you using?