control circuit design

[iceworm]

I don't know what size generator /pump motor you are looking at. Depending on the size, you may wish to consider purchasing an Auto Transfer Switch. Let the float switch controll the generator start. As mentioned, you will have to ginn up some deadband in the float switch so it doesn't short cycle the generator.

An ATS will have all the stuff you need to control the gen and no custom programming - perhaps you would be more comfortable with that.

ice

 

[Smart $]

I would look a lot closer.

No feedback to tell if the genset is on before turning on the pump.

no restart try if the genset does not start.

As I said, a basic circuit.

If I knew the genset remote control protocol, I could design as necessary.

If you want to add system checks, perhaps you'd like to throw in a cellular alarm system just in case it doesn't start at all.

I am not sure what is meant by a "true" off delay, but I am suspicious that it won't work as desired.

True-off delay means the delay starts when relay power is removed. It's wired just like a standard relay. Contacts stay in the energized state until the set delay times out.

For example (not an endorsement): http://peltectimers.com/pdfs/Peltec182-True_off_delay-delay_on_Make_timer.pdf

A typical off-delay relay requires power maintained throughout the cycle, while off delay is triggered through a separate input or circuit.

 

[George Stolz]

Does this get it done?

 

[GoldDigger]

Does this get it done?

Handles everything but failure of the generator to start and restart requests. And it assumes that the generator autostart is a single wire type where a signal on that line is to be maintained for the whole time the generator is running. Also assumes that the E-stop button is not just momentary.
In short, all that is really missing is an assumption or two and bells and whistles to alarm in case of generator failure.

 

[Smart $]

Handles everything but failure of the generator to start and restart requests. And it assumes that the generator autostart is a single wire type where a signal on that line is to be maintained for the whole time the generator is running. Also assumes that the E-stop button is not just momentary.
In short, all that is really missing is an assumption or two and bells and whistles to alarm in case of generator failure.

To add checks and alarm, may as well use a uPLC...

 

[George Stolz]

Handles everything but failure of the generator to start and restart requests.

My thought was that without Generator, 120v, WP would never run, leading LR to run the starter on the generator until there was no more battery.

I have to be honest, I usually do very little with generators in terms of control - usually a closed contact for the duration of the outage makes the generator guy happy and I wash my hands.

And it assumes that the generator autostart is a single wire type where a signal on that line is to be maintained for the whole time the generator is running. Also assumes that the E-stop button is not just momentary.
In short, all that is really missing is an assumption or two and bells and whistles to alarm in case of generator failure.

I think if more were required to get the generator to behave, it would be thrown where OD2 is shown.

If there is no power, I would think nobody would be around to hear an alarm, but that is an assumption on my part.

 

[petersonra]

True-off delay means the delay starts when relay power is removed. It's wired just like a standard relay. Contacts stay in the energized state until the set delay times out.

sounds like what we used to call a pneumatic time delay relay. No way to get that action that I am aware of otherwise. electronic off delay timers require power to the control side of the timer at all times or the contacts will switch when control power is lost. I suppose some kind of internal battery or capacitor could be included to get around that issue.

 

[George Stolz]

sounds like what we used to call a pneumatic time delay relay. No way to get that action that I am aware of otherwise.

Yep, they still make them, and they still fit the bill.

 

[under8ed]

I believe Smart$ has closer to what the OP was looking for in keeping it simple. With that in mind, he had a 120v. on-delay relay instead of the 12v. drawn. I believe it will work with the timer relays the poster had; but as I mentioned in an earlier post, it looks like he will need another low voltage relay to drop out the pump circuit with the existing float. I'd bet he knows where to rob one from something parked on the farm.
I took the liberty to make subtle changes to Smart$ design, though I didn't have his neat program; MS Paintbrush did pretty well. The question about the pump short cycling should not be an issue since it is in service now. The real question is if the "true off" relay is as we believe it to be.
The owner should realize they are passing over on some of fail safe ideas that have been presented here, however: farmers are quite good at knowing risk assessment.

 

[cadpoint]

This came in a promo e-mail the other day!

Electrician's Guide to Control and Monitoring Systems!

Written for 2008 NEC.

I love Books, and I don't have any reference point as to the quality nor
content of the book, but for the price, it tough to beat!

 

[Scott K]

I want to thank all contributors to this thread, I am truly grateful for all the input and assistance. I was able to accomplish my goal by using a "true off" delay relay and an "on" delay relay both with 12v input. It was really quite simple, I was over thinking it and making it more difficult than necessary. I also want to thank Mike Holt for providing this forum, it is an asset to our trade. Thanks again! God bless!

 

[Smart $]

I want to thank all contributors to this thread, I am truly grateful for all the input and assistance. I was able to accomplish my goal by using a "true off" delay relay and an "on" delay relay both with 12v input. It was really quite simple, I was over thinking it and making it more difficult than necessary. I also want to thank Mike Holt for providing this forum, it is an asset to our trade. Thanks again! God bless!

You're welcome...!!!

Glad to hear you got it to work.