TRANSFORMER WIRING

[BARRAQUILLO]

Hi,i'am trying to wire up a 300w submersible transformer.there are no instructions.the 2 cables that come from it are marked 'pri' and 'sec'.my understanding is that 'pri'is the cable connected to the mains,while 'sec' is the low voltage output.whats confusing me is the 'sec' cable is substantially more chunky than the 'pri'.am i right in my wiring?

 

[Doc Hudson]

Welcome to the forum. The principal of a transformer is that they generally transform a voltage down or up. The power consumed on both sides of the transformer remains substantially the same minus any transformer losses. As power = (current x voltage) If the voltage decreases then the current must increase. The size of the conductors has to be large enough to carry the maximum current, bigger currents = bigger wires. So your transformer will have high voltage, low current, small wires on the primary. and low voltage, high current, larger wires on the secondary. hope that helps. I am moving this to the DIY section as I assume you are not a qualified electrician by your question.

Doc H.

 

[BARRAQUILLO]

Welcome to the forum. The principal of a transformer is that they generally transform a voltage down or up. The power consumed on both sides of the transformer remains substantially the same minus any transformer losses. As power = (current x voltage) If the voltage decreases then the current must increase. The size of the conductors has to be large enough to carry the maximum current, bigger currents = bigger wires. So your transformer will have high voltage, low current, small wires on the primary. and low voltage, high current, larger wires on the secondary. hope that helps. I am moving this to the DIY section as I assume you are not a qualified electrician by your question.Doc H.

thanks for responding so fast and sorry i thought this had been posted in diy.So just to confirm the pri connects to the mains 240v,its just that when connected to the mains[but not to any lighting to eliminate any errors downline]it causes the trip to switch and because i had read that high wattage transformers[300w]can cause this due to surge i tried pluging into mains socket supply[as opposed to lighting circuit] and the 13amp fuse in plug blew.do you think it is likely to be a 'dodgy' transformer.thanks,tim

 

[user 15807]

Have you made sure the sec(ondary) wiring is not shorted out? I would disconnect the secondary from the load and try reconnecting the primary side to the mains. Ensure the secondary is insulated or terminated into seperate cinnector blocks before you switch on.

 

[BARRAQUILLO]

rechecked and tried blew fuse again.secondary not connected to anything,just terminal blocks-guessing it must be a faulty transformer!thanks for your help.tim

 

[kme]

If connected properly, then I`d have to say the transformer is faulty mate. Sorry!

 

[Andy™]

probably faulty transformer

you didnt wire it the wrong way to start with, did you?

 

[Doc Hudson]

Has the transformer got any electronics inside it as well and before you asked the question on the forum did you first try connecting up the fat wires to the mains supply? i.e. could you have fried something inside by reverse connection?

Doc H.

 

[BARRAQUILLO]

it's possible,but each time the trip went instantly.i still don't understand why the fat wires go to the low voltage-since low the voltage cable [the cable that goes to the lights]is of a much smaller gauge then the mains cable. that is- mains cable to similar size from pri on transformer heafty cable out from sec. on transformer, just to be connected to the small gauge of the low voltage cable that is run through the garden.

tim

 

[Andy™]

if you wired it wrong, then it will have destroyed it, so no matter wat you do now, it wont work