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Help: Possible Power Jack transformer

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(@sid-genetry-solar)
Member Admin
Joined: 4 years ago
Posts: 2883
 
Posted by: @inphase
Most of it is surely heat dissipation as the limit, beside the obvious physical size limit. Plan the wind around having about 1 tesla flux density. A well designed transformer will have roughly equal volumes of copper on the primary and secondary. Ben knows how to wind a good transformer. I don't know how to tag him but he's searchable here.

@ben the transformer expert on the forums, just don't tell Amber 😉.

Yes, heat dissipation does limit things; however, if the core is good, it seems that the majority of the heat dissipation is a result of losses in the windings.

I determine the winding loss by ohming the coils out: a 50A Juntek CC/CV power supply comes in REAL handy for that!  Once the winding losses are calculated, I can then subtract said known losses from the measured total system losses to determine how much of the loss is accounted for.  And more often than not, most all of the losses are in the windings...leaving comparatively little for the core and switching/FETs.


   
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(@christianrodher)
Active Member
Joined: 3 years ago
Posts: 13
Topic starter  

So just need a big enough coil to give the winding the number of turn necesary for "center taped double cable winding" 120v in 10awg cable for 20amps. i don't know if thats the correct name for that winding lol I saw video that i need to give turn to 2 cables at the same time... then find the center tap and solder those 2 wires together to form the N. 


   
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(@christianrodher)
Active Member
Joined: 3 years ago
Posts: 13
Topic starter  
On 11/25/2021 at 11:04 AM, Sid Genetry Solar said:

Ha, no.  That's a current sense device, you'll blow it up very quickly with 240v.

 

 

Try this:

 

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Being a Chinese inverter, I doubt the ground point will have much to do with anything.  The serious issue comes in if it's tied/coupled to the inverter's "Neutral", which is being used as L2.  Shorting this L2 to the new Neutral generated by the transformer CAN cause serious issues, and it's best left unconnected IMO.

 

It worked! But as you said the transformer is unbalanced. I get 120 from one pole and 110 from the other pole. The inverter is 230vac... Maybe if I buy a inverter 240 I'll get 125 from one pole and 115 from the other pole and make both phases good. 110 is kinda to low.


   
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(@inphase)
Estimable Member
Joined: 4 years ago
Posts: 159
 

110 volts is well within the spec of any 120 V nominal machinery. I wouldn't loose too much sleep over that. Any decently sized transformer won't mind it much either. As long as the waveform isn't going wonky, it's probably OK.


   
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(@sid-genetry-solar)
Member Admin
Joined: 4 years ago
Posts: 2883
 
Posted by: @christianrodher
It worked! But as you said the transformer is unbalanced. I get 120 from one pole and 110 from the other pole.

You can correct this if you have enough heavier gauge wire...if you add ~10 turns to the "low" pole on the transformer, it will increase the voltage.  You can experiment with the number of turns to get it perfectly balanced.


   
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