Powermax 45xp lost arc delay (Solved)

snowgoer540 wrote:

Should be able to use an appropriate SSR in place of a mechanical relay and can successfully use one are two totally different things. I agree in theory they're better, that's why I tried one. In practice, for me, and a few others, they do not work in this application.

This totally ignores the fact that I have a SSR that has been working perfectly at firing the torch on my 7i76e ever since I've been using Plasmac.

For some reason, I always thought Snowgoer was using a 7i96 and on this thread I learn he is using a 7i76 and an external relay.
I always thought he had problems with the internal relays of the 7i96. Now I find thats still sitting in his drawer unused!

Snowgoer has also totally ignored the links and evidence from PCW and myself that SSR's also satisfy the dry contact closure criteria.

Now I find (as robertspark pointed out) that the SSR relay Snowgoer used is marginal in terms of the current range.

In this plasma journey we are all on, there are a lot of unknowns and a lot of things still to discover. None of us can afford to have a closed mind. To have one and be vocal about something to an extent that its "my way or the highway" is not helpful as it just provides static and misinformation for those that follow.

There is no evidence provided from Snowgoer that is relevant to the onboard Mesa relays such as the 7i76/7i76e spindle enable or the 7i96 outputs. Any future user must ignore all of what has been said about Mechanical relays as being mandatory for dry contact closure.

There is no evidence yet that the Mesa on board SSR's are unsuited for plasma operations. You cannot take a single data point for an external relay and apply it to Mesa's onboard SSR's.

In fact, there is evidence that people are using the Mesa relays without problems. I'm now one of them as this thread motivated me to get off my backside and use the spindle enable relay.

tommylight wrote:

I read everything so i know there are 3 cases by now, pretty sure we are going to see more.

Tommy, I am sure you are right as over time, there have been a number users using the Mesa SSRs. Its just that they are out there cutting away and not following this forum becasue they don't have a problem to solve!

I for one am very happy that I have now eliminated all external relays from my plasma table as it will improve the reliability and MTBF.

@PCW
Is the SSR circuit different on the 7i96 vs the 7i76? Would you mind sharing just that part of the schematic with component values? Maybe that will help in diagnosing why there seems to be issues with some peoples SSR for firing the torch.

The circuits are different

The 7I96 has a transformer driven MOSFET
0 to 2A, 0 to 36V less than 1 uA off resistance
less the 50 mOhms on resistance

The 7I76E has a standard Darlington Optocoupler
0 to 50 mA, 0 to 100V ~.7V drop when on
less than 20 uA leakage when off (at 200V)

Both are polarized and will typically show as stuck-on if reversed