hi am looking for a power supply that gives 48v @10amp

[eng-bm]

hi every one its my first time i enter this site
as the subject shows am searching for a circuit diagram of a power supply that gives 48volt at 10amp
so if any one can help me i would be faithful and i will share him my knoldge

 

[gerty]

That's an unsual voltage/current combination.. Have you considered a Variac (variable transformer 0-120 volts ) or you could series two 24v power supplies..

 

[eng-bm]

That's an unsual voltage/current combination.. Have you considered a Variac (variable transformer 0-120 volts ) or you could series two 24v power supplies..

the problem is how to regulate the voltage with this current
i have a transformer that gives 48v @15amp AC
when i put the rectefire bridge the voltage become 48*1.44=68v
so i need a circuit that keep the output voltage at 48v with or without any load

 

[stevez]

A neighbor of mine used to sell power supplies for telephone company use and 48 volts seemed pretty common.

 

[stevez]

Take a look at the datasheet for an LM723 regulator. This is a linear regulator that will require pass transistors that will handle the current requirements. Stuff I am used to seeing uses 2N3055 transistors. This is pretty well established circuitry and there are plenty of other ways to do the job including using switching regulators.

I don't know if the 48 volts RMS from the transformer is enough if you really want 48 vdc and want it with no ripple. With no load the capacitor will charge, as you suggest, to the peak voltage however as you load the supply the voltage will drop. If you use a full wave bridge the voltage available to charge the capacitor never goes to zero but at what point it will drop requires some math. Someone else can probably offer some guidance.

 

[eng-bm]

Take a look at the datasheet for an LM723 regulator. This is a linear regulator that will require pass transistors that will handle the current requirements. Stuff I am used to seeing uses 2N3055 transistors. This is pretty well established circuitry and there are plenty of other ways to do the job including using switching regulators.

I don't know if the 48 volts RMS from the transformer is enough if you really want 48 vdc and want it with no ripple. With no load the capacitor will charge, as you suggest, to the peak voltage however as you load the supply the voltage will drop. If you use a full wave bridge the voltage available to charge the capacitor never goes to zero but at what point it will drop requires some math. Someone else can probably offer some guidance.

i try 2 transistor 2N3055 parell with BD241 as a driver and 48v ziner and i get about 52v out but the ziner get worm even its 3w

 

[Sebi]

As stevez suggested, the 723 datasheet show a "positive floating regulator" solution. With few big transistor(e.g. 2N3055) can build also for 10A output. Also required 30000uF 100V condenser pack for enough filtering. I also worried about 48VAC input voltage, but maybe on transformer have some place for few turns...

 

[eng-bm]

As stevez suggested, the 723 datasheet show a "positive floating regulator" solution. With few big transistor(e.g. 2N3055) can build also for 10A output. Also required 30000uF 100V condenser pack for enough filtering. I also worried about 48VAC input voltage, but maybe on transformer have some place for few turns...

thank you very much mr. stevez for your help
hope to meet again
may i help you
my e.mail is eng-bm@scs-net.org
good bye

 

[eng-bm]

48v 10a power supply

thank you mr sibi (electronic god) for the circuit am looking for easier way
what if i put a transformer of 36v 10a instead of 48v
so i get an output voltage 36*1.414=51vdc
is it ok or this voltage will drop to 36v when i loaded

 

[Nigel Goodwin]

Re: 48v 10a power supply

thank you mr sibi (electronic god) for the circuit am looking for easier way
what if i put a transformer of 36v 10a instead of 48v
so i get an output voltage 36*1.414=51vdc
is it ok or this voltage will drop to 36v when i loaded

Any unregulated PSU will drop under load, the amount of the drop depends on the current drawn and the size of the capacitors.

What is this PSU going to feed?.