TOROID TRANNY WIRING 230v 20va

[cairns4me]

Hey y'all I have very basic understanding about 240v Mains Voltage gear connection which includes EXTREME CARE NEEDED!
So would a kind fellow AK'er please let me know which wire goes where?
The toroid transformer is from Jaycar Electronics Cat MT-2084
Notes on website say: Current ratins on toroidal transformers. Can be used in 2 ways:-
A) Both secondary windings in series - double volts
B) Both secondary windings in parallel - higher amps. The windings need to be connected in phase.
Cat. MT-2084 12+12 Volts 0.833 amps 1.66 amps
THE LABEL ON ACTUAL ITEM BODY SAYS: 240vAC 50Hz BLU-BLU (there are TWO Blue wires within shrink tube sleeve) SEC 15vAC x2 RED-BLK + YEL-ORG
I tried connecting the TWO BLUE to Mains Plug then connected multimeter to Red & Black and got voltage reading of .069 V Connected both probes to YEL & Org and got similar low voltage readings. I stopped whole operation there. Could I ask you guys for help please?
I would like to have the transformer feed a Regulated Linear PSU with the 15vAC at the (HIGHER) 1.66Amps if I can understand how to wire-it. The PSU has screw term block for +V-0-V- btw I DEFINITELY DON"T want the option A) Both secondary windings in series - double volts. Thanks blokes...

 

[mondialfan]

I pulled up the Jaycar catalog and looked at the MT-2084. You had it connected properly, the two blue leads are connected to your 240VAC mains. If you were not reading AC voltage on the RED - BLK or on the Yel -Org leads then you were possibly set on the wrong multimeter mode, were you on AC volts or DC volts? You should be on AC volts. If you were on the right mode then make sure that your leads are good, set the meter for ohms and check the resistance with the two probes connected. I use my meter so much that the leads wear out and one of them will go open on me every 18 months or so. When it does it'll drive you nuts because it'll typically be intermittently good/bad.

For the paralled secondaries you'll connect Red & Yellow leads and the Blk & Orange leads. This will parallel the secondaries and give you the higher current. According to the catalog this is a 12VAC transformer, although you'll see somewhat higher voltage than 12VAC with it unloaded, it is not likely that you'll see 15vac with it under load once its connected to the PSU.

If the PSU you are connecting this transformer to has the inscription +V-0-V- that sure sounds like it needs a rectified DC voltage fed to it and not VAC fed directly from a transformer. Can you post a link to the power supply you're connecting this transformer up to.

 

[whoaru99]

Do you have the multimeter set to read AC voltage?

Have you confirmed the multimeter will correctly read AC voltage?

Have you checked primary and secondary winding comtinuity/resistance?

 

[elnaldo]

I agree, do passive resistance readings on the windings first, no electricity. You must have the same resistance at each secondary, also some reading at the primary.

Your secondary , as the label says, will have 15V AC at each secondary, RED-BLK = 15V AC , YEL-ORG = 15V AC.

If you wire together the black and yellow, you will have 30V AC between red and orange, with a center tap at the black-yellow (or "15-0-15" V AC)

Check if the board you are feeding can receive 30V AC (15-0-15) , or 15V AC total, or +15V / -15V DC. It's labeled +V-0-V- , and AC has no polarity, usually + and - signs usually mean DC, but in Chinese boards everything we think can be wrong.

 

[Hyperion]

The secondary windings should each be marked 0 - 15Vac with an indication of which colour wire is '0' and which is 15vac - thus giving you the correct phasing of the windings.

This is important as, if you connect the windings in anti-phase (parallel) you won't get any output, they should be connected '0' ---> '0' and 15Vac --->15Vac - whichever colours those are.

 

[mondialfan]

BTW Are you certain that Jaycar didn't ship you the MT-2086? Its a 15 + 15 transformer? The 2084 is 12 + 12.

 

[BinaryMike]

This is important as, if you connect the windings in anti-phase (parallel) you won't get any output, they should be connected '0' ---> '0' and 15Vac --->15Vac - whichever colours those are.

If they're parallelled with opposite phase, then you better be sure you've got a fuse upstream somewhere!

 

[elnaldo]

(Thinking out loud, the connectors on the PS board labeled +V 0 -V could be the DC output of the PS)

 

[cairns4me]

Mondialfan & others...Thanks to each of you for your advice. PROBLEM SOLVED

 

[whoaru99]

Mondialfan & others...Thanks to each of you for your advice. PROBLEM SOLVED

Great.

So that others might learn from your experience, what was the problem?

 

[cairns4me]

Do you have the multimeter set to read AC voltage?

Have you confirmed the multimeter will correctly read AC voltage?

Have you checked primary and secondary winding comtinuity/resistance?

Have you got the impression that I am a complete idiot-ie "Have you confirmed the multimeter will correctly read AC voltage?" ?

Great.

So that others might learn from your experience, what was the problem?

Yes I had meant to let you all know that my Multimeter -another quality Jaycar item- was giving erronious readings and turned-out to be faulty...function selector knob had faulty contacts. Cheerfully exchanged it as it was just 4 months young...then everything that young MONDIALFAN explained -so very well- fell into place and all was well. Again thanks to you all -greatly appreciate your efforts to help. Cheers blokes