Ok, so another 262,000 cycles. But this time with the closing contact current stressed to 10 Amps. I pulled the data onto the PC and grouped the opening items into 10 divisions (approx. 26,000 observations in each group).
All I saw was a variation in opening times which would correlate well with the shed temperature over the time it took to fill the memory chip:
Just out of idle curiosity I looked at the closing time. Not expecting anything I was surprised to see two things: Firstly, the time taken to close appears to have an inverse relationship to the time taken to open. As the time taken to open increases, presumably with temperature changes, the time taken to close decreases.
The second thing I noticed was that Group 6 had very little variation. I'm unsure why this is the case and contact bounce could be the reason for this.
And finally, the sum of contact resistance readings for each cycle:
Again, support for changing temperature over the duration of the test can be seen.
However, what I'm not seeing, is degradation. This relay has been subject to over 2 million cycles now. I'll run this test fixture through 260,000 cycles once more before I up the ante because I really want to know what failure looks like.
73's
No comments:
Post a Comment