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smellysell

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So somehow I managed to fry one of my SSRs in my control panel last night. :x

Two questions:

1. Is there anywhere local that sells SSRs? I doubt it, but am hoping not to have to order one

2. If I hook a new one up is the same thing just going to happen again? I did probably 30 or so batches on it with no problem, and have no clue what caused the problem this time.
 

sambogi76

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1. Radio Shack maybe, if you order from digikey you should have it by next weekend.

2. As long as you didn't exceed the amp rating you should be fine. You may want to install a fan to circulate air around your heat sink if you don't have one.
 
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smellysell

smellysell

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1. Radio Shack maybe, if you order from digikey you should have it by next weekend.

2. As long as you didn't exceed the amp rating you should be fine. You may want to install a fan to circulate air around your heat sink if you don't have one.
The heat sink is outside of my box, and never gets very hot. The terminal (probably not the right word) where the power goes into the SSR was actually melted.
 

sambogi76

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Are you sure you had a good tight connection? Or used the right size of wire? That is the only thing that I can think of that would do that (melt). And did you use a good heat sink grease? That would insure that the heat can dissipate from the ssr to the heat sink.
 

kladue

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A cheap and reliable method of monitoring the connections for overheating is to embed dark crayon material in the screw head on the SSR, if it is loose the terminal will heat up and the crayon material will run out. Monitoring the embedded material for melting is an easy way to save the unit from the flame test.
 
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smellysell

smellysell

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Are you sure you had a good tight connection? Or used the right size of wire? That is the only thing that I can think of that would do that (melt). And did you use a good heat sink grease? That would insure that the heat can dissipate from the ssr to the heat sink.
I'm guessing the wire came loose because I had it open messing with stuff recently. Used the right gauge wire and heat sink grease.
 
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smellysell

smellysell

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So I got a new SSR/heatsink combo off of Ebay that of course came without any heatsink grease. I don't supposed there is anything I could substitute for it?
 

Inodoro_Pereyra

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You can buy heatsink grease at radio shack. It's just a couple of bucks.

Make sure you solved the problem that caused the first SSR to blow, or else you probably will have the same outcome.
 
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smellysell

smellysell

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Thanks, I'll hit Radio Shack tomorrow. 99% sure I knocked a wire loose when I was in the control box messing with stuff which caused the problem.
 

onthekeg

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Are you positive the SSR is bad and not just needing a new wire crimp end? Did you actually melt the screw on the SSR that holds the wire?
 

nevertrustahipie

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you really should fuse the SSR (as well as just about everything else). That way when something like this happens again, you only have to replace an el cheapo fuse. As well as preventing fire or injury. :D
 
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smellysell

smellysell

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you really should fuse the SSR (as well as just about everything else). That way when something like this happens again, you only have to replace an el cheapo fuse. As well as preventing fire or injury. :D
:goodposting:

I'll be doing this just as soon as I figure out how to figure out what size fuses I need.
 

Inodoro_Pereyra

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If I were you, I wouldn't calculate the fuse to the SSR Amp rating, but to the load.
Keep the load to a maximum of .707 the SSR Amp rating (which, for a 40A SSR, means 28.28A tops), and calculate your fuse for 1.42 the effective load or higher. For example, if you have a 20A load, your fuse should be 20x1.42=28.4A, so you're gonna need a 30A fuse.
 

Inodoro_Pereyra

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I have about an 18 amp load. Will 30 amp fuses work?

Yeah, with 30A you're good. With that, you will have adequate protection on the whole circuit, plus, since the current through the SSR will never reach its maximum rating, the SSR itself will be protected.
 
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