Power supply problem

[labgruppen]

tama, pag parallel add ang capacitance. tapos kung gusto mong tataas ang voltage, mag series ka. i-check mo yung output ripple kung ok na sa iyo. (use ac coupling sa scope/probe mo. di ako familiar sa simetrix kaya di kita ma-iguide kung paano) kung pasado na sa iyo yang 2200uf, u can use two 4700uf/100 volts electrolytics in series. add ka rin equalizing resistors para siguradong hating kapatid sila sa boltahe. to do this, mag parallel ka ng equal value resistor sa capacitors na i-si-series mo. 4700uf/100V, 6800uf/100V are available locally.

[kinyo]

subukan nga lagyan ng inductor sa output ng bridge para malimit ang inrush current ng C1, halimbawa 100mH

[labgruppen]

subukan nga lagyan ng inductor sa output ng bridge para malimit ang inrush current ng C1, halimbawa 100mH

nice suggestion din ito..

[jep_pogi]

sorry sir kala ko natulog na kayo..
tinry ko po muna ung 2 series na 4700uF capacitors, tas nag parallel ako tig 1k sa bwat capacitor.
ung lumabas na output ay me gantong characteristics:
yung itsura nya is similar sa mga itsura ng output na pinost ko po.
May isang 90A na input current spike ( ung sa time = 0secs), tas sa steady state 25A max ng 3mSecs na current spikes.
Ripple voltage after the diode bridge = 4V peak.
Ripple voltage at the output = 2mV peak.
Output current = 3A

yung sa inductor po tinry ko rin, kaso ung output malabo e, o mali lang ako ng connection. pati mtaas po ung ripple voltage ng after sa diode bridge. nilagay ko lng ung inductor after ng bridge papunta sa node ng C1.

[jep_pogi]

papasok muna po pala ako ng school. try ko po ulit mag sweep ng values mamaya. thanks po, reply po sana kayo ulit mamaya ^^

[kinyo]

sobra yata mataas yung 100mH ... subukan na lang 10mH or lower   

[labgruppen]

yung sa inductor po tinry ko rin, kaso ung output malabo e, o mali lang ako ng connection. pati mtaas po ung ripple voltage ng after sa diode bridge. nilagay ko lng ung inductor after ng bridge papunta sa node ng C1.

tataas talaga ang ripple voltage sa node ng inductor at bridge rectifier. expected yan, at ok lang yan. ang importante ay yung ripple voltage c1 at most importantly ang ripple voltage sa output. though mataas yung ripple voltage sa node ng bridge at inductor, dapat bumaba na yung magnitude ng current spikes mo sa bridge/capacitor.

[jep_pogi]

sirs,
eto po ung circuit na latest, pinagsama ko ung inductor na 10mH suggestion, pati ung 2 series capacitor with parallel resistors each:


tas eto po ung voltage response, ung RED ay sa node after ng inductor, so xa ung sa node din ng capacitors.
tapos ung GREEN ay for the output voltage na nilalabas nya.


tapos eto nmn sa current response, YELLOW ung across sa capacitor c1, tas red po yung output less than 3.5A


bumaba ung current spikes. is this better?
baka po may masuggest pa kayo.

and pwede po ba paexplain kung anu gnagawa nung inductor?

[jep_pogi]

ill wait for your reply sirs. thank you

[labgruppen]

kung accteptable na sa iyo yung spikes, then ok na. Ilang volts ba ang required output? mukhang 72 volts lang yung zener string mo. Tapos 1W lang, parang kapos yan. Approximately 58.9mA yung constant current source mo, round off na lang sa 60mA. So 60mA*18V(zener voltage of 1n4746)>1W. I suggest na stick with the 5watt zeners. You could also make your zener like this.. 3pcs *1n5355B + 1n5359B + 1n4733A.  Across 1n4733A connect a 100 ohm trimpot in parallel. This will provide you with adjustability from approx. 78V to 83V.

[jep_pogi]

anu po ba yung "acceptable" na spikes? di ko po kasi talaga alam e. pero mas mababa na po yung spikes na yan kumpara dati.
200A dati ngaun 30A nlng po.

wala po sa simetrix nung 1n53XX series e, sila ung 5W, meron lng ung 1n47 which is mga 1W. pero opo mag stick ako sa 5W nlng na zener diodes to be sure.
okey po gusto ko din itry ung suggestion nyo, okey xa. di ko nga lang masisimulate kulang sa parts sa simulation e..tatry ko isimulate sa 1W na zeners pero similar na values ng voltages ng zeners.

pwede din po ba na 3pcs *1N5359B + 1pc *1N5344B? total po nyan is 80.2V
kaso ang publema di ko xa masisimulate kung gagana ba xa.

pati sir, ung current output pala sobrang nagdedepend sa load no, di pa kasi ako sure kung ilan ung resistance ng AC servo motor na load. sana nasa range ng 20's din para maka 3A

[jep_pogi]

sir tinry ko pla to knina
ung sa zener string, ginawa ko 3pcs *1N4749(24V 1W) + 1pc *1N4738(8.2V 1W)
pero hindi xa gumagana, hindi daw nagcoconverge ung sa simulation, so most probably di xa pwde rin in real life.
bkt po kaya?

sir, ung "test current" ba na nasa data sheet ng mga zener diodes, sila ba ung minimum reqd current para gumana ung zener sa gusto nating region? kasi kung ganun, dapat gagana ung kahit anung zener na pinili natin e. kasi more than the "test current" xa na nasa datasheets.

[jep_pogi]

uhm sir isa pa pong question, sorry.
tingin nyo po ba okey na yung diode bridge na 1N5401? 100v 3A po xa na rectifier diode

[labgruppen]

sir tinry ko pla to knina
ung sa zener string, ginawa ko 3pcs *1N4749(24V 1W) + 1pc *1N4738(8.2V 1W)
pero hindi xa gumagana, hindi daw nagcoconverge ung sa simulation, so most probably di xa pwde rin in real life.

I beg to differ, most probably gagana sa real life.  Not sure whats happening with simetrix, di ko pa kasi nagagamit yan. Pero sa pr0t3us, gumagana sya.  I also simulated yung variable output, gumagana din.

sir, ung "test current" ba na nasa data sheet ng mga zener diodes, sila ba ung minimum reqd current para gumana ung zener sa gusto nating region? kasi kung ganun, dapat gagana ung kahit anung zener na pinili natin e. kasi more than the "test current" xa na nasa datasheets.

Yung test current, yun yung actual current nung kinuha nila yung value ng zener voltage. It is sort of the current na guaranteed na tama yung zener voltage. This is usually at around 25% ng maximum current keeping the power dissipation at about 25% ng maximum power dissipation. Nag-vavary din kasi yung zener voltage as a function of the current due to the zener diode's impedance.  Now, you should already have an idea why I opted to bias the zener diodes with a constant current source, and not with a simple current limiting resistor.
You should not exceed the zener diode's maximum power dissipation.

[labgruppen]

anu po ba yung "acceptable" na spikes? di ko po kasi talaga alam e. pero mas mababa na po yung spikes na yan kumpara dati.
200A dati ngaun 30A nlng po.

Magdedepende yan sa specs ng capacitor at diodes mo. But don't worry too much about it. Yung mga DIY amps na ginawa namin dati, walang in-rush current limiter. And we used transformer with higher capacity which means less winding resistance thus larger currents possible, and the capacitors are doing fine. If you want to really minimize in-rush current, you could place an NTC thermistor in series with the transformer's primary. The high cold resistance of the thermistor will limit the in-rush current. As the thermistor heats up, its resistance becomes lower and it will become negligible. This technique is used by some major brands of professional audio power amps.

pwede din po ba na 3pcs *1N5359B + 1pc *1N5344B? total po nyan is 80.2V

yes, pwede.

pati sir, ung current output pala sobrang nagdedepend sa load no..

of course, sa load magdedepende yung output current.

.. di pa kasi ako sure kung ilan ung resistance ng AC servo motor na load. sana nasa range ng 20's din para maka 3A

I thought alam nyo na yung power requirements nung motor + motor controller ninyo...

uhm sir isa pa pong question, sorry.
tingin nyo po ba okey na yung diode bridge na 1N5401? 100v 3A po xa na rectifier diode

Better use 1n5402 for loads up to 2A to have a margin of safety. If you expect higher load currents, use diodes with higher current capability.

[labgruppen]

Better use 1n5402 for loads up to 2A to have a margin of safety. If you expect higher load currents, use diodes with higher current capability.

In case you will be wondering why I recommended 1N5402, it is due to the fact that your peak voltage is at 120V, thus your PIV is greater than 100V which is the absolute max. for 1N5401.

[jep_pogi]

mga sir, sana po magreply kayo ulet.
narevise ko na po ulet ung circuit, pero this time tinanggal ko na ung inductor, pati inayos ko na ung specs ng transformer at load resistance.
okey na ung output nya. about 75V 2A pwede na po sa akin.
tanong ko lang po, kasi ideal transformer ginamit ko sa simulations ko, kaya tingin ko magkakapublema dun.
kapag saturable transformer na, di ko na alam panu specs ilalagay ko.
reply po sana kayo masters.. thanks

[labgruppen]

saturable transformer? imho, there is no need to use this model for the reason that you do not yet know the parameters of your transformer will be. the ideal transformer simulation is enough.
i think you have done more than enough simulating. simulation can not really substitute the real thing, so why not proceed with the next step, building it. it is not a complicated design anyway, unlike other topologies with op amps and feedback that are prone to oscillate if not properly designed. first design a pcb and present it here for comments. also finalize the specs of your transformer and send it to your preferred builder. medyo matagal ang lead time nun so you have to consider it, baka magipit kayo sa oras.

[jep_pogi]

alam ko na po yung specs ng transformer, ewan ko po kung kulang pa to, pakisabi nlng po kung ano pa kulang.
eto ung specs na sasabihin ko po:
220Vac primary
64Vac secondary
approx 2.2A sa output so di ko pa po alam kung ilang current sa secondary side dapat.
tapos sa simulation, 10mH yung primary inductance ng transformer (ewan ko po kung kelangan pa to sabihin dun sa gagawa)
magsisimula na po ako magdesign, bukas kung mafinalize na po ngayon, magpupunta na sa Raon.

[labgruppen]

64Vac secondary
approx 2.2A sa output so di ko pa po alam kung ilang current sa secondary side dapat.
tapos sa simulation, 10mH yung primary inductance ng transformer (ewan ko po kung kelangan pa to sabihin dun sa gagawa)

yung primary voltage, secondary voltage and secondary current lang naman ang kailangan nilang info.  about your current requirements, it all depends on your load. ano ba ang maximum na expected current draw ng load ninyo? add 25 percent for a reasonable margin and that's it imho. you should have now finalized your current requirements kasi dyan magrerely yung specs mo for transformer, rectifier diode and series pass element and heatsink. and of course the fuses.