You could go with a 24VDC to 120VAC inverter and a stepdown transformer to 24VAC but it would be a kludge. Building an inverter is not a simple task and is usually cheaper to buy one already made due to the costs of the individual parts alone.

 

There are several questions to be answered before a schematic can be devised.
Do you need 24V RMS - that is one issue already as it needs a peak of about 34V - higher than the 24V DC line.
If you need 60Hz (I guess) then it would be conceivable to use an ordinary transformer which had a step-up ratio, but that may be more expensive than a common 120/240 to 24+24 or similar (two primary, two secondaries). Then you need to generate the 60Hz signal. Or possibly use a 120:80V transformer (or 120:40+40) where the secondary is run from the 24V and the output from the primary (i.e. backwards) but that would need a push-pull AC feed (essentially 16V AC, allowing for some losses) and the transformer would be larger than necessary in order to get the output current, Though I take it the power level is low so that may not be too much of an issue.
So what you are looking at is:
probably a 60Hz signal generator
some form of power amplifier
a suitable transformer
which amounts to an inverter, but delivering a sinewave is not too efficient, perhaps 70% if lucky.
A switch mode power supply might deliver 24V AC 60Hz more efficiently but would need an oscillator, modulator drivers, an HF transformer, and suitable filtering or could possibly be driven from a microprocessor.

If the AC you need can be 24 V square wave you might get away with a simple push pull single transformer design with a simple 60Hz oscillator.

It might be cheaper to run a new cable supplying 24V AC from a transformer from your main supply.

So, a schematic is not quite as simple as asking for one without more detail!

 

But that’s not his requirement

Whoops.
My dyslexia kicked in again.

Sounds like a purchased DC to AC inverter, such as this, would be the best way to go if you don't have an AC source available.

 

, such as this, would be the best way to go

I am looking for 24Vac 50/60hz also but to test water valves. (lawn sprinkler valves)
I have a large irrigation system where most of the valves are not at the source of water but are where the water is used. It would be wonderful to clip onto a valve and watch it work with out walking long distances.
Thanks for the information.

 

There are several questions to be answered before a schematic can be devised.
Do you need 24V RMS - that is one issue already as it needs a peak of about 34V - higher than the 24V DC line.
If you need 60Hz (I guess) then it would be conceivable to use an ordinary transformer which had a step-up ratio, but that may be more expensive than a common 120/240 to 24+24 or similar (two primary, two secondaries). Then you need to generate the 60Hz signal. Or possibly use a 120:80V transformer (or 120:40+40) where the secondary is run from the 24V and the output from the primary (i.e. backwards) but that would need a push-pull AC feed (essentially 16V AC, allowing for some losses) and the transformer would be larger than necessary in order to get the output current, Though I take it the power level is low so that may not be too much of an issue.
So what you are looking at is:
probably a 60Hz signal generator
some form of power amplifier
a suitable transformer
which amounts to an inverter, but delivering a sinewave is not too efficient, perhaps 70% if lucky.
A switch mode power supply might deliver 24V AC 60Hz more efficiently but would need an oscillator, modulator drivers, an HF transformer, and suitable filtering or could possibly be driven from a microprocessor.

If the AC you need can be 24 V square wave you might get away with a simple push pull single transformer design with a simple 60Hz oscillator.

It might be cheaper to run a new cable supplying 24V AC from a transformer from your main supply.

So, a schematic is not quite as simple as asking for one without more detail!

60Hz and it can be a 12VDC to 12VAC it is to trickle charge a Ring door bell. I would of installed a 120v to 24v transformer if I could. I am not able to run new wires as it is surrounded with plaster. So again 12V DC to 12 or 24V AC. Sounds like it is to complicated request. I will resort to pulling the battery and charging it as needed.

 

I am looking for 24Vac 50/60hz also but to test water valves. (lawn sprinkler valves)
I have a large irrigation system where most of the valves are not at the source of water but are where the water is used. It would be wonderful to clip onto a valve and watch it work with out walking long distances.
Thanks for the information.

I installed Rachio sprinkler controller. We have 16 zones and it works from my phone I can walk through our property turning on and off valves. It is really handy when needing to repair heads.

 

I installed Rachio sprinkler controller. We have 16 zones and it works from my phone I can walk through our property turning on and off valves. It is really handy when needing to repair heads.

Nice, I have a home sprinkler system. I have tried to get it on the network but it would take too much programming. My system is hooked to a well that will run dry if used hard. I have not found a controller that will stop when there is no water. Also stops if the wind is fast, or switches to garden and tree in the wind. I will look up Ranchio, thanks.

 

Nice, I have a home sprinkler system. I have tried to get it on the network but it would take too much programming. My system is hooked to a well that will run dry if used hard. I have not found a controller that will stop when there is no water. Also stops if the wind is fast, or switches to garden and tree in the wind. I will look up Ranchio, thanks.

It is linked to a weather station so you can program not to run in wind. It also does automatic seasonal adjustments. If you do intermittent watering you should not run your well dry, I would hope. Rachio.com

 

It is linked to a weather station so you can program not to run in wind. It also does automatic seasonal adjustments. If you do intermittent watering you should not run your well dry, I would hope. Rachio.com

Is you current controller close to your water pump? Most pumps have an automatic shut off. If so you could tap into that line install a relay then connect the NO relay to the common wire going from the valves to controller. You will need a WIFI signal going to Rachio

 

Is you current controller close to your water pump? Most pumps have an automatic shut off. If so you could tap into that line install a relay then connect the NO relay to the common wire going from the valves to controller. You will need a WIFI signal going to Rachio

Off-topic? Please respect the TS.

 

Where is the NuTone speaker box? I ask because part of your requirements is a constraint on the inverter size.

So if you don’t have enough space, would you consider cutting in another box next to or near to the NuTone box, into which an inverter and a transformer could fit?

Construction wise, cutting in an auxiliary box is simple. Which would lessen one of your constraints.

 

Making one assumption, that the power source generating the 24vdc is from line voltage (say 120v), how about simply a 120v to 24v transformer and a 24vdc relay? The dc will switch both legs of 24vac.

 

Making one assumption, that the power source generating the 24vdc is from line voltage (say 120v), how about simply a 120v to 24v transformer and a 24vdc relay? The dc will switch both legs of 24vac.

Chris, PLEASE read the original post. It is from a Nutone system.

Where is the NuTone speaker box? I ask because part of your requirements is a constraint on the inverter size.

So if you don’t have enough space, would you consider cutting in another box next to or near to the NuTone box, into which an inverter and a transformer could fit?

Construction wise, cutting in an auxiliary box is simple. Which would lessen one of your constraints.

If it were drywall no problem It is stucco and I don't want the cover plate out there.

 

Chris, PLEASE read the original post. It is from a Nutone system.

If it were drywall no problem It is stucco and I don't want the cover plate out there.

So what’s on the inside opposing the stucco?

 

So what’s on the inside opposing the stucco?

Does not matter.

 

Most bell systems work on low voltage AC

OK ...

due to the distance/voltage loss of DC wiring.

Ummm ... No.

For the same voltages (RMS vs. DC) and the same load currents (RMS vs. DC), the power loss in the wiring is identical. (We'll ignore the AC power loss in the wiring distributed capacitance.)

ak

 

1. Any guess as to the peak current drawn by the trickle charger?

2. Thinking about ground isolation ... Do you know if there is a galvanic connection between the DC system and the Ring doorbell? The question here is whether or not the 24 Vac source has to be floating (transformer-isolated) - ?

TS: Please post a block diagram of the components and their interconnections as you envision things.

ak

 

This was my first post to a forum. The amount of wasted chatter was unbelievable. People posting totally irreverent questions and ignoring the simple question 12 or 24 VDC to 12 or 24vAC a schematic plain and simple. No answers. End this, it can't be done. End this thread.

 

Of course it can be done. In fact, it can be done in so many ways that without more information from you the question is too unbounded to answer. Consider two 555's driving a small audio output transformer.

I think your attitude is based more in arrogance than in reality. Your first post was not nearly as wonderous as you think. After 16 posts by you we still do not know the output current or isolation requirements. Without that information, why would anyone (who knows how to do this, which is most of us) begin?

This is a free help community, not a service bureau. You are not paying by the hour or the minute, and chatter is a fact of life in online fora. I suggest you lose the attitude, answer the questions, post a wiring diagram, and lose the attitude.

ak

 

The help here is free and worth every penny.
If that's not satisfactory to you, then you are certainly free to ask your question elsewhere.

So what was the problem with my off-the-shelf solution in post #23?