ECN Forum Forums Technical Discussion Electrical Theory and Applications Help... Virgil's baffled by control work again...

Don,
I understand your point that you don't want the motor to restart at the end of the timer cycle if there is still an obstruction. But that wouldn't happen anyway.

If a cow is still blocking the gates when the timer N/C contact opens, the relay will still be held energized by the closed limit switch and the motor won't start until the limit switch opens.

Paul,
I guess that I was overlooking the fact the the time delay relay contact and the limit switch contacs are in parallel.
Don

For a while I was beginning to think that I was missing something.

Virgil,
Have you stripped this lot down yet? Is it just a motorized timer?

Yes, a motorized timer, 120V SPDT.

I had some time this week to disect what I had and get the ball rolling, but they haven't installed the components yet, and I think it's kind of low priority.

Had a big hassle installing a delay timer for the wash cycle for the milk tanks. The problem was that the milk truck driver would set the tank to wash cycle after draining it, but this was usually after wash down in the parlor, so the water tanks weren't hot enough and the bacteria counts became high.

No problem says I, I'll put in a time delay relay and a bypass switch... But little did I know that the first relay I bought had a bad timer (digital) and, not being real confident in my control work, I assumed that I had done something wrong. This is complicated by the fact that the only time to troubleshoot is between the time the truck empties the tank and before the wash cycle. Being further complicated by a weeks delivery time for the relay (Glad I put in a bypass). Being further complicated by not really being sure if the relay was bad...

It was. *whew*

Who pays for the time that it took me to figure it out? The customer? (not his fault) Me? (Not completely my fault) Or my supplier? (yeah, right)... I guess me.

I know that feeling. At a house I worked on last year the owner needed three dimmers, two of which were controlling large chandelier-type light fixtures totaling about 400W each.

Despite my misgivings about using the lowest-quality 500W dimmers, the builder insisted we go with the cheapest versions (a make I have had experience with before and would never run at more than about half their rating given a choice).

Guess who had to go back and change two of them for better quality replacements, and trek down to the supply house to get a refund on the faulty units?


[This message has been edited by pauluk (edited 09-08-2002).]