SSR Heat Concerns

I built a small power distribution box in a 6x6x4" weather tight PVC box.
It's built to power a 1500 watt rims heater, 2 March pumps and a control panel.

It is tight... It has 2 duplex outlets with the hots all separated. One switched outlet for each March pump, one unswitched outlet for the control panel and one outlet controlled by a 40a SSR and switched. There is a control line between the two boxes for the PID/SSR interface.

I was/am concerned about heat build up because I mounted the 40a SSR and heatsink INSIDE the box.

To get an idea how this was going to work, I ran the PID in manual mode at 50% and plugged a 1680 watt heatgun into the SSR controlled outlet. I also ran one of the march pumps just circulating water. I closed up the box as best I could (I left one of the outlet covers off so I could get a temp probe inside) and ran it for 3 hours. It got up to about 100F and that's where it was 3 hours later.

The Auber SSR has an operating temp range up to 70C.

Thoughts?


Ed

Ohio-Ed said:

I built a small power distribution box in a 6x6x4" weather tight PVC box.
It's built to power a 1500 watt rims heater, 2 March pumps and a control panel.

It is tight... It has 2 duplex outlets with the hots all separated. One switched outlet for each March pump, one unswitched outlet for the control panel and one outlet controlled by a 40a SSR and switched. There is a control line between the two boxes for the PID/SSR interface.

I was/am concerned about heat build up because I mounted the 40a SSR and heatsink INSIDE the box.

To get an idea how this was going to work, I ran the PID in manual mode at 50% and plugged a 1680 watt heatgun into the SSR controlled outlet. I also ran one of the march pumps just circulating water. I closed up the box as best I could (I left one of the outlet covers off so I could get a temp probe inside) and ran it for 3 hours. It got up to about 100F and that's where it was 3 hours later.

The Auber SSR has an operating temp range up to 70C.

Thoughts?


Ed

Click to expand...

I'd be worried about that. I've seen about 1 watt per amp come off the SSRs. If you mount the SSR to the box, you can cool from the outside maybe? If you're just running 1700 watts you might get away with it.

Ohio-Ed said:

I built a small power distribution box in a 6x6x4" weather tight PVC box.
It's built to power a 1500 watt rims heater, 2 March pumps and a control panel.

It is tight... It has 2 duplex outlets with the hots all separated. One switched outlet for each March pump, one unswitched outlet for the control panel and one outlet controlled by a 40a SSR and switched. There is a control line between the two boxes for the PID/SSR interface.

I was/am concerned about heat build up because I mounted the 40a SSR and heatsink INSIDE the box.

To get an idea how this was going to work, I ran the PID in manual mode at 50% and plugged a 1680 watt heatgun into the SSR controlled outlet. I also ran one of the march pumps just circulating water. I closed up the box as best I could (I left one of the outlet covers off so I could get a temp probe inside) and ran it for 3 hours. It got up to about 100F and that's where it was 3 hours later.

The Auber SSR has an operating temp range up to 70C.

Thoughts?


Ed

Click to expand...

Ed,

I know this is a old post, but I am looking to build the exact control box you have described above. Can you provide me with some feedback and best practices based on what you have done?

Thanks,
Joe

If you must, mount the ssr inside of the enclosure and the heatsink on the outside of the enclosure.

How bout some "shielded vents"? That'd go a long way to cooling her off.....

jmsullivan73 said:

Ed,

I know this is a old post, but I am looking to build the exact control box you have described above. Can you provide me with some feedback and best practices based on what you have done?

Thanks,
Joe

Click to expand...

I built a PID into a small project box to use as a digital thermometer. Later, I added connector to tie to the "Power Distribution" box I described above.

I was willing to risk burning up a SSR to see if this would work. I used it a few times, but quickly progressed to a BCS controlled system.

I don't know of anyone else that has measured the internal temperature of their control panel. As I said in an earlier post, under 50% duty cycle and a pump running for 3 hours, the temp never exceeded 100f which is 37.8c. The operating range of the auber ssr is up to 70c.

The box I used is very small for all the stuff I crammed into it.
There are NO fuses or over current protection in this build and the wiring is a rats nest.

I had no problems with it in probably 6-8 brews that it was used in. I still use the "Digital Thermometer" portion on occasion.

If I did it over (which I did), I would build in over current protection, try to dissipate the heat outside the box, and be more organized with the wiring. Here is some pictures of the whole setup and some details of each box:

The copper tube is a homemade 24" thermowell with a PID inside.


One of the connectors is for the RTD, the other connects the PID box to the Power Distribution box. The switch near the cord is a power switch, the switch near the front is to turn off the alarm.


The 9v battery powers the alarm





The connector ties the Power Distribution box back to the PID box via an "Umbilical" cord.





The PID Box, plugs into the "unswitched" receptacle so there is only one supply line required.




All 12awg wire, very little room.


Ed