New Panel Advise

[Ohio-Ed]

I just got a deal on a new NEMA Type 1 metallic box. I have been gathering some components to build a control panel and have started thinking about the layout.

I'm wondering if I can mount the SSR's on the inside and have the heat sinks on the outside of the box.

What are your thoughts about sandwiching the side of the metal NEMA box between an SSR and the heat sink?

Will the box help dissipate the heat or will the paint prevent the heat transfer?

Any thoughts or advise would be appreciated.

Thanks
Ed

 

[Sawdustguy]

I just got a deal on a new NEMA Type 1 metallic box. I have been gathering some components to build a control panel and have started thinking about the layout.

I'm wondering if I can mount the SSR's on the inside and have the heat sinks on the outside of the box.

What are your thoughts about sandwiching the side of the metal NEMA box between an SSR and the heat sink?

Will the box help dissipate the heat or will the paint prevent the heat transfer?

Any thoughts or advise would be appreciated.

Thanks
Ed

No good. In that case the enclosure will be your heat sink. The enclosure may have enough surface area to dissipate the heat, but I can't be sure and the enclosure may be hot to the touch. Putting the heatsink inside is not a good solution either if the box will be closed up. If you decide to put the heatsink inside the enclosure, cut a ventilation hole and mount a fan to it. Whatever you do, don't forget to put a generous amount of thermal transfer goo between you heatsink and SSR.

 

[JKoravos]

The paint probably provides a little bit of thermal resistance, as does the steel box material, but it's not terribly much. If you're pushing the limit of the SSR, you may want to think about having direct contact with the heatsink. If you're only running it at 50% of the rated load, or thereabouts, mounting through the box is probably fine.

 

[Ohio-Ed]

Thanks for the feedback guys.
The problem is that the 40a SSR and the heat sink I got from Aubers are virtually the same size. The heat sink has provisions for mounting on the opposite end, but that would put the SSR on the outside of the box. I'd really like to have the SSR in the box and the heat sinks outside.

What do you think if I cut a larger hole in the box and mounted a piece of aluminum via pop rivets. Then sandwiched the aluminum between the SSR and heat sink (with thermal goo on each side of the aluminum)?

Thanks
Ed

 

[Sawdustguy]

Thanks for the feedback guys.
The problem is that the 40a SSR and the heat sink I got from Aubers are virtually the same size. The heat sink has provisions for mounting on the opposite end, but that would put the SSR on the outside of the box. I'd really like to have the SSR in the box and the heat sinks outside.

What do you think if I cut a larger hole in the box and mounted a piece of aluminum via pop rivets. Then sandwiched the aluminum between the SSR and heat sink (with thermal goo on each side of the aluminum)?

Thanks
Ed

That would definetely work. If possible, use a piece of copper instead of aluminum. I used to design RF power amplifiers and the transfer of heat between the power devices and the heat sink was always better with a copper spreader. Aluminum will do, but copper is optimum. Definetely put thermal goo on each side.