Dodgy dave, I don't think that putting a transformer on will work in this case, Correct me if I am wrong but that will emit Magnetic/RF interference without a faraday cage?? This power supply is going on my nephews " FPV base station" rc controls using 72.mhz, 433mhz, 1.3 ghz and 2.4ghz frequencies. any unfiltered system will cause interference wont it?

This is why I am trying to find out a very simple low rf interference solution

A mains transformer will not interfere with radio frequencies.

 

PUT A TRANSFORMER ON THE LIVE AND NEUTRAL, that way your post wont get deleted, as for the circuit you need to detect anything over 150V.

By definition, the generator in this discussion is an isolated source.

 

If you don't use a transformer, the power supply on this site will be classified as "Transformerless" and is Forbidden on here, so your post will be closed down,

Yes i agree with the idea of not using a transformer.

 

I like the idea of using a 240VAC relay on the power line.
Now install a manual power switch on the input of the transformer windings.

Post a clear warning that the power switch must be OFF before plugging into power outlet.

If you don't like this solution, then install a latching relay instead of the power switch.
Put a momentary NO pushbutton on the power supply.
After you plug the unit into the mains outlet, push the push button to energize the relay.
The human supplies the turn-on delay.

 

Here's my concept to avoid any significant mains powered electronics.
It uses two relays with the second relay delayed from the first.
This assumes the 240Vac relay does not pull in in on 120Vac.
R1 is selected (based upon U2's coil resistance) to limit the U2 coil voltage to its rated value. It may have to be a power resistor, depending upon the relay coil resistance.
C is selected to give an RC time constant of probably a half second or so.

 

Here's my concept to avoid any significant mains powered electronics.
It uses two relays with the second relay delayed from the first.
This assumes the 240Vac relay does not pull in in on 120Vac.
R1 is selected (based upon U2's coil resistance) to limit the U2 coil voltage to its rated value. It may have to be a power resistor, depending upon the relay coil resistance.
C is selected to give an RC time constant of probably a half second or so.

View attachment 119489

Yes, that should work. You may need a resistor in series with the first relay coil as it may still pull in at 110V but that's easy enough.

 

Alec please send me a link on where to purchase a voltage sensing threshold circuit or if not can you tell me how to build one with a schematic and parts list

Sorry, I have no link for such a circuit. It would probably need to be designed. The circuit in post #39 is not recommended as a starting point.
Crutschow's suggestion in post #45 looks good. Perhaps use a 1N4007 rather than a 1N4004 for D1?

 

Perhaps use a 1N4007 rather than a 1N4004 for D1?

Good point.
The momentary reverse peak voltage should be less than 400V, but extra margin is good so a 1N4007 would be better.
Likely the price difference is insignificant.

 

I have for got to mention that there will be a fast blow 1a 250 fuse installed between the mains and the generator, and a dc 8 amp fuse on the dc output side of the ac to dc power supply as well as a master kill switch on the ac in, this way the entire system will be isolated 3 ways if there is a problem. also the AC cord has a female end connector that connects to the base station, this connector is magnetic connection, (like on a deep frier) so that if it is tripped over, or in case of emergency, it pulls out in one fast move. The on board batteries are also isolated in a power failure 12v relay NO, this disconnects everything on the up end side.

 

Here's my concept to avoid any significant mains powered electronics.
It uses two relays with the second relay delayed from the first.
This assumes the 240Vac relay does not pull in in on 120Vac.
R1 is selected (based upon U2's coil resistance) to limit the U2 coil voltage to its rated value. It may have to be a power resistor, depending upon the relay coil resistance.
C is selected to give an RC time constant of probably a half second or so.

View attachment 119489

Hello Crutschow, I am liking this design few components, this is looking more like what I am trying to do, so what you are saying is to use (2) 240v relays, one 1N4007, (1) resistor, and (1) capacitor to build the system correct? what would be the suggested relays, resistor and capacitor???
The system will be cuttoff from the mains with a master switch the kills all power to everything so this is not a problem.

 

I have found this to help us out http://www.mouser.com/ProductDetail/Mean-Well/LRS-150F-12/?qs=/ha2pyFadugebngm2XBQAib6wR5%2bDBfsgZkqS4LiPit570F0OHniPw==

http://www.mouser.com/ds/2/260/LRS-150F-spec-806315.pdf look at page 3 this is exactly what I am trying to do, there are 2 problems 1. the country where I am living at currently does not have these available, so I have to build it, and 2, page 3 does not tell me what components are needed to make the detection circuit. I am hoping there is some one out there that can help here. this is what I brought with me from the states.http://www.ebay.com/itm/AC110V-220V...233795?hash=item281ffafb03:g:etoAAOSwi0RX0epR there is an actual physical switch to select between 110v and 220v, the mouser one seems to do it automatically, how?

 

As already explained they do not have a switch to select the mains voltage they simply work correctly across the whole range of voltages.

 

so what you are saying is to use (2) 240v relays, one 1N4007, (1) resistor, and (1) capacitor to build the system correct?

Not necessarily.
The second relay has to pull in at about 100Vdc since it needs to operate from rectified 120Vac through the delay circuit..
A 220Vac relay may pull in with 100Vdc but I need to know the exact relay you plan on using.
Note that the first relay only has to carry the coil current of the second relay, so it can be smaller than the second.

 

As already explained they do not have a switch to select the mains voltage they simply work correctly across the whole range of voltages.

Albert I thank you sincerely, Please remember my background is not in electronics, and I am probably old enough to be your father 87 years young. I am trying my hardest to understand this without a completed diagram that I can see and copy. So using what I have how do I make it work. I need a diagram to follow.

 

Here's my concept to avoid any significant mains powered electronics.
It uses two relays with the second relay delayed from the first.
This assumes the 240Vac relay does not pull in in on 120Vac.
R1 is selected (based upon U2's coil resistance) to limit the U2 coil voltage to its rated value. It may have to be a power resistor, depending upon the relay coil resistance.
C is selected to give an RC time constant of probably a half second or so.

View attachment 119489

Crutschow, you make the recommendations of all the parts and I am sure I can find them, there is a large electronic parts store that sells building circuit parts, and they can cross almost anything and have a mess load of electronic parts.

 

It does not look like a power supply to me.

It is a good idea to use isolation when testing.

 

It is a good idea to use isolation when testing.

At a minimum, only operate the circuit from an outlet with a GFI or GFCI (Ground Fault Interrupter).

 

At a minimum, only operate the circuit from an outlet with a GFI or GFCI (Ground Fault Interrupter).

All the sockets here in the house are ground fault protected, For testing I have a 110/220 220-110v inverter that automatically cuts out if there is a problem. I do not have 220v available as a standard connection here at the house.

 

It does not look like a power supply to me.

It is a good idea to use isolation when testing.

Dick I have a 110/229v -220/110 inverter that faults dead when there is a problem, I think this is isolation you mean, + all the plugs are gif ground fault sockets.

 

This is not the answer to your question. The idea is to replace the power input connector. (Asssuming it does have one and not just a power cable.) If you fitted a 6 pin connector you could use some pins on it to change the voltage tapping. You could then have different power cables with US plugs and others for european plugs on them.

Les.