Circuit diagram

[Geo-TH,In]

Been thinking of designing a circuit to connect to my 110v RV genny so when the well pump draws current, all other loads like ref, 110v kitchen appliances are removed with a 3 minute delay built in. The delay will be needed to give the ref a 3 minute rest for pressures inside to equalize. That way if the pump runs for only one minute, the ref will get 3 minute rest.

Been designing this in my head. Haven't put it to paper yet. I'm just throwing it out there for the experts to post their designs first.

May consult Bubba. All good redneck make things from used or on hand electronics components. May have to check his inventory of supplies.

George

 

[MarkB_MI]

Hmm. If you wanted to do this using only solid-state components, I'd say switch the refrigerator power using a triac. Which means you'd need a way to turn the triac off when the pump is running. A 555 timer one-shot circuit could be used to generate a three-minute pulse. Probably the easiest way to switch the triac using the low-level DC output of a 555 is to use an optical isolator; there are devices made specifically for this purpose.

 

[Greg K]

I'm thinking, the pressure switch pulls in the contactor for the well pump and also energizes a timing relay that shuts down the contactor that feeds everything else. I can't draw so a diagram is out of the question. Like everything else, it works in my mind!

 

[Part Time Pete]

I'm not sure you would need the delay, as the well pump should only run for a few minutes anyway. I would use an ice cube relay with the same coil voltage as your pump, to open up the other circuits when the pump comes on.
Pete

 

[DENNIS MIN]

Part-time-pete,

Time delay relays are not that expensive. I have one that triggers some select electrical loads for a limited duration every time something metallic cross my driveway, like a car for example.

D.

 

[hanovertom (VA)]

Try some FM dust, but don't let the smoke out!

 

[Steve@Advance]

If I were designing this, I would start with a "double throw" relay to power the well pump.

Use the normally open contacts to power the well, the normally closed contacts to power the other accessories.

Then install a 3 minute "on delay" relay on just the refrigerator.

 

[jeffcat]

Guys all of this is pointing to a bigger and or correct sized gen- set?

 

[Geo-TH,In]

jeffcat,
Point to being frugal. How much will it cost to operate if I hooked up a pto genny to my tractor, run the tractor at full speed to power up a well and refergerator? IMHO, it's like using a cannon to kill a house fly, over kill.

My 3500-4000peak RV genny will run on a gallon of gas for 3 hours at half power, 67 db at 23 ft. If gas is $4, that's $32 a day in fuel. Can't imagine what it would cost running a tractor. My jubilee would use about 2-3 gallons an hour.

The device I'm going to make will use parts from old furnaces and air conditioners. One part is special, but it can be pruchased from a HVAC supplier. I think I have all the parts, if I can find the special part, a current relay.

My goal is simple. This device will be self contained. Plug device in to genny. It will have 3 outlets. One for pump, so when pump kicks on, everything will be turned off. When pump is off, one outlet will come back on right away, for coffee pot, toater, even microwave, using only a few at at time. The third outlet will come on 3 minutes after the pump is off to power ref.

This device isn't rocket science, yet no one has attempted a circuit diagram. Where are all the EE's and electricians, technicians? I'll post diagram and proto type when I get it together.
George

 

[MarkB_MI]

>This device isn't rocket science, yet no one has attempted a circuit diagram. Where are all the EE's and electricians, technicians? I'll post diagram and proto type when I get it together.

George, don't expect someone to cough up a detailed design if you haven't provided any details yourself. Your original post gave no info as to what devices you intended to use or detailed requirements such as it being a standalone device. Also, you say you want to do it on the cheap, but I don't think current-sensing relays are particularly inexpensive.

Certainly such a device can be done with relays. It can also be done with solid state devices. Since you specify you want to use relays, I'm not going to waste my time drawing up a schematic that uses solid-state devices.

 

[david - or]

Here you go. The timing relay can be obtained from automationdirect.com for $37.00

The current sensor can be had from automationdirect.com for $63.50

The other relays can be had from junked appliances or ebay.

 

[Geo-TH,In]

Dave,
Congrats, Looks like your circuit will work. I'm still looking for my current relay. May have to order one. I have used relays form furnaces. Good Job.
George

 

[Geo-TH,In]

Mark,
All the components Dave used are used in furnaces and air conditioners. There are current sensors on ebay under $20. Make on delay timers are cheap too. My sister is in the HVAC business. I can get parts drop shipped even cheaper. I worked on testing my used components yesterday. Still need to locate my current sensor, it's hiding someplace. Next I need to find an old load center to put everything in.

The clue to my post was "parts that Bubba has on had". Bubba doesn't know anything about Triacs, zeners.

I would have thunk more experts would have come up with a diagram. Really hoping to see something I hadn't thought about.

This was just for fun, however I'm going to find it pratical when I lose power.

George

 

[JMOR]

(quoted from post at 09:12:58 12/30/13) Mark,
All the components Dave used are used in furnaces and air conditioners. There are current sensors on ebay under $20. Make on delay timers are cheap too. My sister is in the HVAC business. I can get parts drop shipped even cheaper. I worked on testing my used components yesterday. Still need to locate my current sensor, it's hiding someplace. Next I need to find an old load center to put everything in.

The clue to my post was "parts that Bubba has on had". Bubba doesn't know anything about Triacs, zeners.

I would have thunk more experts would have come up with a diagram. Really hoping to see something I hadn't thought about.

This was just for fun, however I'm going to find it pratical when I lose power.

George

useful device might be the "compressor protection module" that prevents the compressor from being short cycles by operator or thermostat chatter or power interruption. It provides a couple of minutes time delay at any time power is applied/removed from it. 4 terminal device found in Lennox A/C condensing unit and likely any other high end A/C units.

 

[Geo-TH,In]

Jmor,
I'm going to use what I have on my shelf, Supco TD60, delay on make timer that will pick up a 24 vac relay. This type of adjustable delay timer is used on many centeral A/C's.

I had to order a current sensor. Should get it by Saturday.

Friend is looking for an old load center or electrical box to put this in.

Post pics when I get it finished.

George

 

[MarkB_MI]

George, I have no problem with your decision to use relay logic. It's reasonably simple and reliable. Of course I had no idea what devices you might have on hand. My shop inventory includes plenty of discrete electronic devices but not a single relay.

Going all solid-state would allow a smaller package, but that benefit is offset by increased complexity and extra time debugging the circuit.

 

[Geo-TH,In]

Steve,
My pump will be wired direct. Current relay will turn off the rest of loads. However if there is a delay in the current sensor, the relay I'm using is a SPDT. Not sure the contacts can handle the LRA of pump, that's why pump I'm wiring the pump direct. Also the 3500 watt genny can handle the pump by itself.

Hope you can see why I want to make this device. The well only runs for a few minutes, so why have a huge genny that costs more to operate.

Keep in mind, this has to be redneck. Use spare parts on shelf.
George