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pcmccartney1

5VDC Circuit Breaker

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I'm in need of ideas.  I have customer that is using Allen-Bradley 1769-IG16 - 16 Channel TTL Input Modules and are insisting that no fuses be used.  Rather, they want a circuit breaker to protect the card and the 1606-XLP25A 5VDC Power Supply.

My google searches found Phoenix Contact having an electronic circuit breakers to protection of 12VDC devices, but not down to 5VDC.

Anyone know of a vendor or even a part number of a circuit breaker for 5VDC circuits?

Possibly, the only solution is fusing. 

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that card has 74HCT14 at inputs. those are low current CMOS chips and they draw under 4mA each. since they are six buffers per chip, there will be three of those chips in one input card bringing current draw to a whopping 10-12mA at 5VDC. add few mA for the IR optocouplers and you may get up to 25mA or so of total draw with all inputs on.

if i was adding protection, i would try to pick different PSU, something with protected output - one that has overvoltage protection. otherwise I would add own overvoltage protection in a form of a fast acting 5.6V zener or TVS  and then adding small fuse. otherwise, maybe add in a circuit breaker for client so they can... switch it off...?

 

 

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Posted (edited)

Thanks @panic mode.  Will investigate.

 

Update! Found a Phoenix Contact Circuit Breaker with a thermomagnetic that handles 0-50VDC.  The datasheet stated the operating voltage as 50VDC.  Not even as a range.  But upon testing it proved to work for 5VDC.

Edited by pcmccartney1

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