Aqua Logic Transformer

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rajthepilot

Active member
Jul 13, 2022
27
Indianapolis, Indiana, USA
I've bene spending time learning the technical side of the pool equipment. I had a question about the transformer and the two rectifiers. Based on the pictures below, the transformer has two output wires (K - Both Yellow) (to get 24 VAC), but 4 input wires of 120 VAC (H - Gray, Violet, White and Blue). Why does the transformer need 4 inputs of 120 VAC?

Also based on the pictures below. Two Orange Wires (J) with 24 VAC are going to the rectifiers, one to each rectifier. Red and black are coming back from the rectifiers with 18-33 VDC and red and black are connected to each other. Can anyone explain how this circuit works. I understand that rectifiers use diodes to convert AC to DC, but then why use two rectifiers and why are red and black connected to each other and also why do the two orange go to separate rectifiers (assuming one orange wire is hot and one orange wire is neutral with 24 VAC)?
 

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The transformer has two sets of primary windings so that it can take an input of 120 volts or 240 volts.

For 120 volts, the windings are in parallel and for 240 volts, the windings are in series, which gives each winding 120 volts because, in series, the voltage is divided.
 
rajthepilot said:
I've bene spending time learning the technical side of the pool equipment. I had a question about the transformer and the two rectifiers. Based on the pictures below, the transformer has two output wires (K - Both Yellow) (to get 24 VAC), but 4 input wires of 120 VAC (H - Gray, Violet, White and Blue). Why does the transformer need 4 inputs of 120 VAC?
Click to expand...

The transformer can be wired for 120V in or 240V in. The other wires are used with a 240V connection.
rajthepilot said:
Also based on the pictures below. Two Orange Wires (J) with 24 VAC are going to the rectifiers, one to each rectifier. Red and black are coming back from the rectifiers with 18-33 VDC and red and black are connected to each other. Can anyone explain how this circuit works. I understand that rectifiers use diodes to convert AC to DC, but then why use two rectifiers and why are red and black connected to each other and also why do the two orange go to separate rectifiers (assuming one orange wire is hot and one orange wire is neutral with 24 VAC)?
Click to expand...
AC alternates positive and negative. To transform it to DC you need one rectifier when negative and one when positive.
 
1707433572918.png

The Red wires go on the + terminals, which are the terminals that are turned relative to the other three and sometimes are marked by a cut corner.

The black wires go on the opposite terminals, which are the (-) terminal of the DC.

The yellow or orange are the AC from the transformer.

1707433648151.png
 
I would love to see the engineer's explanation for why there are two bridge rectifiers and they are only using 1/2 of each. I could hazard a guess that they ran into heat dissipation limits on the part, but if that is the case surely it would cheaper to use a single larger part and/or a better heatsink.
 
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By changing the jumpers, the transformer can take 120 or 240 volts.

In the below picture, it is set for 240 volts and the windings are in series.

If you change the jumpers, it can take 120 volts because the windings are in parallel.

The AquaLogic and ProLogic are set up for 120 volts only and the jumpers are only used on the Aquarite.

You can "theoretically" use 240 for the Prologic by wiring directly, but this is not something you should do unless you understand everything about the wiring and even then, probably not a good idea.


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Hello. @JamesW I have a quesiton related to this same transformer. A friend of mine has this hayward panel that has stopped working. I will be canabaliing parts from the hayward panel and implmenting nodejs pool controller Nixie for them. I will use this transformer for 24vac and 24vdc with the rectifiers. Ideally I can remove the old board and direct wire to the transformer which is current fed with 120v to the board.

From what I follow in the above, I would use the yellow wires as 24vac output, tap the yellow wires with the orange wires to feed 24vac to the rectifiers and use the red and back wires from the rectifiers as the 24vdc output. How would I connect the 120v input to the GRY, VIO, BLU and WHT wires? Also should I include an inline 20a fuze on one of the yellow wires to mirror the exisitng PCB mounted fuse?
 

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mhmatttu said:
From what I follow in the above, I would use the yellow wires as 24vac output, tap the yellow wires with the orange wires to feed 24vac to the rectifiers and use the red and back wires from the rectifiers as the 24vdc output. How would I connect the 120v input to the GRY, VIO, BLU and WHT wires? Also should I include an inline 20a fuze on one of the yellow wires to mirror the exisitng PCB mounted fuse?
Click to expand...
That diagram @JamesW posted implies you'd connect gray and white together and to one side of the 120vac line. Also blue and white together and to the other side of the line. It would be an excellent idea to add a varistor across the AC line as shown to protect from power surges. Also fuse the secondary at 20A or less as shown.
 
Thank you. To clarify, I assume you meant connect gray and vio to one side of 120v and wht and blu to the other side of 120v, correct? That makes sense from the jumper diagrahm.

Lastly, how critical are the vaisistors and fuse? After adding the cost of those to the mix, might just be best to get a new 24vac transformer
 
mhmatttu said:
Thank you. To clarify, I assume you meant connect gray and vio to one side of 120v and wht and blu to the other side of 120v, correct? That makes sense from the jumper diagrahm.

Lastly, how critical are the vaisistors and fuse? After adding the cost of those to the mix, might just be best to get a new 24vac transformer
Click to expand...
No that's backward. Gray and white to one side. Blue and violet to the other. You'll want a varistor and fuse no matter what transformer you use. They're safety devices. This thing will be running 24x7 in or near your house. If something in the system goes sideways, the fuse prevents a fire. The varistor prevents the whole gizmo from being fried by a voltage spike (e.g. lightning strike), which can also end in fire.
 
mhmatttu said:
would the varisistors be wired in series with each 120v side and the combined colored wires such as below?

View attachment 575927
Click to expand...
Nope. They need be directly across the 120v line.

Try redrawing the circuit @JamesW posted except with two jumpers between 1+2 and 3+4 as for 120vac. You'll see the 120v lines connected to white+gray on one side and blue+violet on the other. Both of the varistors will be across the 120v line.

Incidentally, you can probably get away with only a one varistor, but 2 is fine and maybe a bit safer. Mouser wants only 0.79 a piece, so it's not worth the trouble to do the numbers.

The varistor's job is to normally be like an open switch unless the voltage across them reaches something like 300 as during a power surge. Then they become a short in order to absorb the surge energy and ultimately cause the upstream breaker to trip. To do this they must be directly across the mains.
 
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