Perry Babin said:
Perry,
the winding ratio you posted earlier for me....is it gona be the same for this core?
aliazhar said:
I did Get a hold of Matt through the Forum email link at the bottom of his post. He still has torroids available. They are super efficient. The primary has 3mm of wire (soldered end) using 6 strands. secondary has 2.5mm using 4 strands for each winding.
2pist said:
thanks for the info....as i mentioned earlier, i have already ordered toroids....so, I will have to check them out first myself before order these...
to tell you the truth, buying something will kill the whole fun of DIY ! 🙂
Thanks again!
since i am waiting for toroids, i thought, 'lets try again with this SMPS till i get toroid'...and got some positive results...
I had another E-Core from Magnetics, which i have bought from surplussale....
first the winding:
1.7mm wire = 2x 4-turns (4-0-4)
0.4mm wire= 6x 16-turns
test results:
Idle amp usage: 200 miliamp
Load:
36v 3amp = 108 watt
battery amp use on the above load= around 12 amp ( ~ 140 watt)
Thermal condition using a normal heatsink of 1"x1/2"x4" on each side:
on the above load, it gets a little warm after about 6 minutes.
now, do you guyz think that its a good result?....
i am using a standard schematic from this thread with 4 mosfets in total.
mosfets used are: STP80NF06
please post your opinion on these results.
I had another E-Core from Magnetics, which i have bought from surplussale....
first the winding:
1.7mm wire = 2x 4-turns (4-0-4)
0.4mm wire= 6x 16-turns
test results:
Idle amp usage: 200 miliamp
Load:
36v 3amp = 108 watt
battery amp use on the above load= around 12 amp ( ~ 140 watt)
Thermal condition using a normal heatsink of 1"x1/2"x4" on each side:
on the above load, it gets a little warm after about 6 minutes.
now, do you guyz think that its a good result?....
i am using a standard schematic from this thread with 4 mosfets in total.
mosfets used are: STP80NF06
please post your opinion on these results.
The thicker the cross section of wire the more current you can push... are you laying the wire strands flat or twisted around the core?
Hi
More wire more current yes and no, since skin effect comes into play here. Do you have any wire close to 1mm, which should be good to use, and if you do have, use 4x1mm for each primary, 2x1mm or what you have just more wires for each sec...with usage of large core this should be good for 1kw, so have I been told
with toroid you remember that each winding, pri or sec must be spread on whole core (primary, where it starts, there should end, or very close, after making one turn), same for sec, which can do more turns
More wire more current yes and no, since skin effect comes into play here. Do you have any wire close to 1mm, which should be good to use, and if you do have, use 4x1mm for each primary, 2x1mm or what you have just more wires for each sec...with usage of large core this should be good for 1kw, so have I been told
with toroid you remember that each winding, pri or sec must be spread on whole core (primary, where it starts, there should end, or very close, after making one turn), same for sec, which can do more turns
I have just received toroid core and am going to wind them...
just a quick question:
primary and secondary winding in the same direction or opposite direction?
just a quick question:
primary and secondary winding in the same direction or opposite direction?
Hi
All the same... see who wires create magnetic flux in core, be sure that each primary or secondary in on whole core...
All the same... see who wires create magnetic flux in core, be sure that each primary or secondary in on whole core...
did that....and there is a big voltage drop at the output...
at the moment, i am still using the basic pcb design...with 4 mosfets as in this post...
primary: 22-awg 5x 4-turns (4-0-4)
secondary: 26awg 4x 18-turns (single winding)
help ! 🙂
why voltages are dropping? any remedy for this?
at the moment, i am still using the basic pcb design...with 4 mosfets as in this post...
primary: 22-awg 5x 4-turns (4-0-4)
secondary: 26awg 4x 18-turns (single winding)
help ! 🙂
why voltages are dropping? any remedy for this?
Hi
Is your input canstant? That is way to much drop, even if you would have wrong core, check everything again, how your windings are in right directions...did you look at waveform?
Is your input canstant? That is way to much drop, even if you would have wrong core, check everything again, how your windings are in right directions...did you look at waveform?
ok....re-checked everything...found a short at the output...my fault...sorry.
now after that, i have tested it with a 100watt load...
here is the test:
smps output voltages: 44.5
output load: 100w (17.5v 5.5amp)
voltage drop: from 44.5v to 39.5 volts
now, the question:
1. why there is a voltage drop, when i have a regulation?
2. one side of the mosfets is getting a bit warm...and the other is normal temperature....why only one side is warm?....
Thanks again for all your help !
now after that, i have tested it with a 100watt load...
here is the test:
smps output voltages: 44.5
output load: 100w (17.5v 5.5amp)
voltage drop: from 44.5v to 39.5 volts
now, the question:
1. why there is a voltage drop, when i have a regulation?
2. one side of the mosfets is getting a bit warm...and the other is normal temperature....why only one side is warm?....
Thanks again for all your help !
ok...after reading/searching the forum....i did some experiments....
and now the output voltages are 99.99% precise....not even 0.01 volt drop !!!!
initially, this circuit was working at 63Khz....so, I have reduced the pwm to 25khz....and added about 10% addition in the secondary winding...
by doing that, voltages are stabalized and i dont see any drop at all.
I am now, ready to increase the number of mosfets to total 12 as Perry advised and then will post the results.
Thanks again everybody !
and now the output voltages are 99.99% precise....not even 0.01 volt drop !!!!
initially, this circuit was working at 63Khz....so, I have reduced the pwm to 25khz....and added about 10% addition in the secondary winding...
by doing that, voltages are stabalized and i dont see any drop at all.
I am now, ready to increase the number of mosfets to total 12 as Perry advised and then will post the results.
Thanks again everybody !
one more thing i have noticed.....which is very important....
mosfet temperature is normal.....they are not even warm...
before, with the same load, they were getting warm....
mosfet temperature is normal.....they are not even warm...
before, with the same load, they were getting warm....
Perry Babin said:
Perry,
Thanks again for showing me the right choice....this is really a perfect toroid !!
one question:
on load of about 300 watts....i am facing a voltage drop of about 3-volts....
i have played with changing the frequency (a bit lower/higher) but, its not effecting.....
any suggestion to regulate it more efficiently?....
on load of about 300 watts....i am facing a voltage drop of about 3-volts....
i have played with changing the frequency (a bit lower/higher) but, its not effecting.....
any suggestion to regulate it more efficiently?....
Assuming that the input B+ supply isn't dropping significantly...
Increasing the ratio and/or reducing the loss due to resistance (shorten wires or increase diameter of wires between components) will help. If you're still using 5x22g for the primary, you're probably getting quite a bit of loss there also.
Increasing the ratio and/or reducing the loss due to resistance (shorten wires or increase diameter of wires between components) will help. If you're still using 5x22g for the primary, you're probably getting quite a bit of loss there also.