Is there a transformer builder here that knows what is required to transfer a few amps at 12 or 24 volts inductively with no contact? From what I can figure out I need to design a SMPS with a transformer that has physically separated input and output windings. The transformer design is what I'm having trouble with.
I'm trying to figure out the construction of the transformer. I can't have a common core between both windings. I'm trying to figure out if I just need a couple large diameter loops or some sort of core. In this application the secondary coil is going to physically move away from the primary loop now and then. It's really just eliminating a set of contacts when they are close together.
I've seen cutting a toroid in half, with primary on one and secondary on the other.
Issue is, when they are separate that the primary coilset doesn't kill the drive circuitry. The inductance gows down when they decouple, so you may need a detector circuit that ramps conversion down when it detects the two are apart, and pings to see when they come back together.
jn
Many smps transformers are gapped. If you design the circuit with an appropriate gap built in, it'll work. There's a lot of parameters you need to consider to really engineer it. If you use a pair of neo magnets on each side to magnetically clamp the toroids together, you could add another magnet that a reed on the supply side sees to turn on the drive.
jn
As I understand it, you have some kind of rolling door or gate which usually is in a fixed (closed) position , which needs to be illuminated (safety reasons?) and needs to stay illuminated while opening and closing or while staying open.
Is that so?
One standard solution would be using some kind of rolling contacts along a powered rail ... I can understand you don't want that, at least I wouldn't either
Another would be to have some coiled cord hanging from a pole (say, 2X as tall as the door, or more) and some spring attached to it, so it follows the gate .
Being a 12 meter long movement, I also wouldn't like that very much.
So you want contactless energy transfer.
Problem is, you can have that, like in some "cordless" cellphone chargers, but only transfering quite low power (a couple watts?) and across a few mm distance (5 mm?)
But if you need to transfer 100/200W or more ("a few amps at 12/24V" which to boot makes me think you will use very inefficient car type filament lights) and even worse, at greater distances, your
Besides safety problems mentioned by DF96, Canadian Radio/Communications Authority will jump to your neck.
With due respect, I'd suggest:
1) cut radically power consumption by applying LED strips to the gate, which will be VERY visible.
FWIW I'm repairing a traffic signal head, the pedestrian one with red "stop" , white "go" and a microprocessor countdown showing seconds left so you either hurry or decide not crossing, with 2 matrixes of red and white high efficiency Leds.
These Leds are blinding ; I imagined they were run at 30 to 50 mA or so .... they run at 3 to 4 mA !!!!! Incredible.
That's why I suggest LED strips.
2) attach a small box to some convenient point on the gate so it does not block movement, and house there a 12V 7 AH "alarm/gel" battery.
If freezing temperatures don't allow that, get some battery pack (Lithium? ... NiMH?) which is rated for your expected temperature range.
3) add a pair of contacts (I knew you wouldn't like it ) so when gate is closed, a trickle charger keeps the battery topped up; when gate opens you have a few hours autonomy; maybe even an hour is more than enough.
4) if you wish, make it smart: with gate closed it displays so or lights only white LEDs or whatever; with gate open it lights red ones or makes them blink or whatever you choose.
5) it's safe, less than 20V DC involved, no radiation of any kind.
A couple large, spring loaded contacts on each side (aluminum strips?) will make alignment much less critical.
Is that so?
One standard solution would be using some kind of rolling contacts along a powered rail ... I can understand you don't want that, at least I wouldn't either
Another would be to have some coiled cord hanging from a pole (say, 2X as tall as the door, or more) and some spring attached to it, so it follows the gate .
Being a 12 meter long movement, I also wouldn't like that very much.
So you want contactless energy transfer.
Problem is, you can have that, like in some "cordless" cellphone chargers, but only transfering quite low power (a couple watts?) and across a few mm distance (5 mm?)
But if you need to transfer 100/200W or more ("a few amps at 12/24V" which to boot makes me think you will use very inefficient car type filament lights) and even worse, at greater distances, your
becomes a very high power, illegal transmitter antenna.
Besides safety problems mentioned by DF96, Canadian Radio/Communications Authority will jump to your neck.
With due respect, I'd suggest:
1) cut radically power consumption by applying LED strips to the gate, which will be VERY visible.
FWIW I'm repairing a traffic signal head, the pedestrian one with red "stop" , white "go" and a microprocessor countdown showing seconds left so you either hurry or decide not crossing, with 2 matrixes of red and white high efficiency Leds.
These Leds are blinding ; I imagined they were run at 30 to 50 mA or so .... they run at 3 to 4 mA !!!!! Incredible.
That's why I suggest LED strips.
2) attach a small box to some convenient point on the gate so it does not block movement, and house there a 12V 7 AH "alarm/gel" battery.
If freezing temperatures don't allow that, get some battery pack (Lithium? ... NiMH?) which is rated for your expected temperature range.
3) add a pair of contacts (I knew you wouldn't like it
) so when gate is closed, a trickle charger keeps the battery topped up; when gate opens you have a few hours autonomy; maybe even an hour is more than enough.4) if you wish, make it smart: with gate closed it displays so or lights only white LEDs or whatever; with gate open it lights red ones or makes them blink or whatever you choose.
5) it's safe, less than 20V DC involved, no radiation of any kind.
A couple large, spring loaded contacts on each side (aluminum strips?) will make alignment much less critical.
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Contacts aren't really an option here due to weather and driving skills of our show removal operators. I can mount coils high up so they don't actually hit them. When they bend the posts I can just realign them. Contacts require a little better alignment.
This will be an LED warning circuit. I've looked into them a little farther and the lamps I would prefer to use are 12 volt 340 mA units and there will be three of them so the current requirement isn't really that high after all. I don't need them on while the gate is open so there is no storage needed. I've been looking at pre-built coils. They are either 5 or 7 volt 10 watt units. Most of these units are packaged with a battery charge control circuit that I don't really need. I can probably work with something like this if I build my own lamp modules. The next hurdle would be temperature as I would likely need to encapsulate them in epoxy.
I am very familiar with traffic indicator LEDS. I've used them in many automotive applications for signalling. Most of my stock requires higher current draw to extend the life of the LED itself but I'm sure there is newer lower current technology out by now.
This will be an LED warning circuit. I've looked into them a little farther and the lamps I would prefer to use are 12 volt 340 mA units and there will be three of them so the current requirement isn't really that high after all. I don't need them on while the gate is open so there is no storage needed. I've been looking at pre-built coils. They are either 5 or 7 volt 10 watt units. Most of these units are packaged with a battery charge control circuit that I don't really need. I can probably work with something like this if I build my own lamp modules. The next hurdle would be temperature as I would likely need to encapsulate them in epoxy.
I am very familiar with traffic indicator LEDS. I've used them in many automotive applications for signalling. Most of my stock requires higher current draw to extend the life of the LED itself but I'm sure there is newer lower current technology out by now.
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