Shutdown timer

[nxslt1]

I'm looking for a timer that I can't find and might not exist. What I need is to shutdown something if it has ran for longer than about 45 seconds. It's a safety to keep it from running for hours on end. Basically, it needs to sense when the equipment has ben turned on whether thru voltage or amp sensing, then start a timer and if it still senses voltage or amperage after the set time then shut down a relay and stay shut down. If the equipment stops running before it times out then it needs to reset the timer and wait for the next cycle. Does this exist?

 

[D.A.(Tony)Stewart]

Is there a sensor that shuts down the equipment or is it manual?

Unlikely to find what you asked for but it certainly can be built.

 

[KlausST]

Hi,

depending on what needs to be shut down ..
* a watchdog circuit could work
* a timer relay
*
...

for 45s a simple RC timer is not precise enough.
Ah yes, precision. Are we talking about 45s +/- 1ms or 45s +/-5s?

I´m not sure whether we speak about a 3.3V 10mA DC device or a 10kW, 3 phase 400V AC device. or anything inbetween.

What about giving a bit more informations?

Klaus

 

[D.A.(Tony)Stewart]

It is not an off the shelf item as described. But the logic to design it as accurate as necessary is possible.
Insufficient specs were given to do so.

 

[barry]

I think a simple off-delay relay would work. Apply power to the relay, it energizes for a certain amount of time and then de-energizes. To restart, you’d have remove and re-apply power. Actually, you could use a push button switch to energize the relay, use a NO contact of the relay across the switch to keep power appled to the relay. when the relay de-energizes, the contact across the switch opens, ready for the next cycle.

 

[FvM]

Agree with barry that an industry standard universal timer relay can implement the function. It comes with a 5 or 10 A rated output contact. Timer is usually triggered by a 24V or 230V input (can be e.g. 10 to 230 V wide range). Current sense would be an additional function, there are 1 to 3 phase load current detectors with adjustable threshold available of the shelve.