Hey guys, I am having some solid state relays fail during short circuit at the output, and I am wondering what a better way might be to protect them?
This is the relay I am using:
TLP3546A(TP1FCT-ND
3.5A continuous current draw
10.5A current draw for a maximum of 0.1 second pulse
And this is the fast blow fuse I am using:
0698Q3150-01
3.15A Fast Blow
They are typically used at 12 or 24 volts, AC or DC.
At modest and large current overloads, the fuse trips no problem, and nothing bad happens to the SSR.
During a short circuit, the fuse also trips, but the SSR sustains permanent damage and is now permanently in the ON position. Some times the SSR survives this, but most of the time it does not. It seems the fuse is not fast enough for short circuit protection. Here is the schematic:
Is there a better way of protecting against short circuits?It seems like a "Ultra-Fast-Blow" fuse would work, or a semiconductor fuse, since they react so quickly that it would save the relay.... however, I can't really find any reasonable ones for a 2.5 to 3.25 amp protection.
I also considered incorporating a series resistor on the output to try and limit current... but even then it seems I would have to use a massively sized resistor, and it would emit a lot of heat.
Are there any other options you can think of? I was almost wondering if there might be a way to accomplish this with some sort of a current draw sense circuit that could react faster than the fuse, and shut off the output before damage occured. Not really sure though.
Thanks and any help or advice is greatly appreciated!
This is the relay I am using:
TLP3546A(TP1FCT-ND
3.5A continuous current draw
10.5A current draw for a maximum of 0.1 second pulse
And this is the fast blow fuse I am using:
0698Q3150-01
3.15A Fast Blow
They are typically used at 12 or 24 volts, AC or DC.
At modest and large current overloads, the fuse trips no problem, and nothing bad happens to the SSR.
During a short circuit, the fuse also trips, but the SSR sustains permanent damage and is now permanently in the ON position. Some times the SSR survives this, but most of the time it does not. It seems the fuse is not fast enough for short circuit protection. Here is the schematic:
Is there a better way of protecting against short circuits?It seems like a "Ultra-Fast-Blow" fuse would work, or a semiconductor fuse, since they react so quickly that it would save the relay.... however, I can't really find any reasonable ones for a 2.5 to 3.25 amp protection.
I also considered incorporating a series resistor on the output to try and limit current... but even then it seems I would have to use a massively sized resistor, and it would emit a lot of heat.
Are there any other options you can think of? I was almost wondering if there might be a way to accomplish this with some sort of a current draw sense circuit that could react faster than the fuse, and shut off the output before damage occured. Not really sure though.
Thanks and any help or advice is greatly appreciated!