Max cycle count of a relay on 1769-OW16

As Johnny Cash would have said "I've been everywhere Man"

Surfed the net for three hours, finally gave in and asked Rockwell. They said they would get back with me.

I have used their Motor starters/contactors, the have the life time cycles listed on the branding. But they cannot tell me how many cycles the relays in the 1769-OW16 are good for.

Anybody have anything close to a clue about this.

Your time and attention to this very minor detail is greatly appreciated.

Thank you

Omron has some data on this, I seem to remember seeing a failure rate of 1 in 1,000,000 in 10,000 operations, others in the past have quoted 300,000 as life expectancy, however, this will depend on the current drawn & the contact rating, I have seen 14 machines run for 16 years & only one failure on a relay output card, these relays would operate typically between 14,000-16,000 times a day 7 days a week, these typically drove 24v solenoids not high power but given the mechanical operations this i think was exceptional. I was surprised that the machine builder used relay outputs on a machine that would typically operate that many operations, we had another machine which if you like was doing even less operations with a IMO plc, this took relays out at the rate of one or two every 3-4 months. We replaced the relays on a regular basis & put in place a project to replace it with transistor outputs, The engineering buyer got it wrong & ordered a Mitsubishi relay output PLC, we fitted it anyway as it was too late to wait for a replacement, however, it never failed a relay for the 7 years it was in service, so the real answer is how long is a piece of string.

The quick answer

I'm in agreement with the previous post but the quick sarcastic answer to this one is "If you have to ask it's probably a poor application and needs to be done another way". There's a lot of good solid-state choices out there today.

Proper use of arc suppression makes a different. Use flyback diodes across teh coils of inductive DC loads. AC tends to give a longer relay contact life than DC.

I would go with 1,000,000 operations to be safe, if your process requires more than that in it's life then you should be using solid state or triac.
think about it, a machine that switches a contactor on 100 times an hour, that's 800 per 8 hour shift, 4000 per week on a 5 day 8 hour i.e. 40 hrs, in a year that is 280,000 per year based on a 40 hour week, so based on 1,000,000 operations it won't last more than 5 years, but most plants probably work 24/5 so that is 624,000 in the first year. Anything switching more than a couple of times an hour I would put in solid state.