Series and parallel

[chng7]

Hi there, let's say I have two 24V DC powered appliances, and I would parallel them up and use a 24V DC power supply to power the appliances.

However, what would happen if I series them up and use a 48V DC power supply instead?
Both appliances are resistive load and has the same power rating. If I series them up, I will end up with smaller current, am I right?

Please help.

 

[davelerave]

they'll work either way in theory

 

[pushrod]

Hi there, let's say I have two 24V DC powered appliances, and I would parallel them up and use a 24V DC power supply to power the appliances.

However, what would happen if I series them up and use a 48V DC power supply instead?
Both appliances are resistive load and has the same power rating. If I series them up, I will end up with smaller current, am I right?

Please help.

It depends where you are measuring the current.

You will have the same current going thru each appliance , but in the parallel circuit you will have double the current leaving the power source but then it will split in two.
If say the resistance was 6 ohms for each appliance when they are in parallel total R = 3ohms. Then I =V/R 24/3 = 8amps, but then it will split so 4 Amps goes thru each appliance.

When they are in series but you have doubled the power source in series then total R = 12 ohms (6+6) and V =48, so I =V/R =48/12 =4amps, but this 4 amps will go through both appliances.
.

 

[mikejashley]

Pushrod is correct in current calcs but if it is a 24vdc appliance you are wiring in reality it is a lot easier and cheaper to source a 24v psu, a 48v psu would probably be made from putting 2 x 24v psu's in series which would double the cost

 

[pmac10]

pushrod is indeed correct but the dc output voltage is unlikely to be two 24vdc psu s in series, voltage output from rectified ac is dependant on things such as thyristor firing angle or transistor switching frequency with regards to the supply and other mind bending electronics not a couple of 24v units in series

 

[chng7]

Many thanks to everyone. The reason I would like to series the two components is because I wanted to reduce the amps drawn from the power source, as it is limited by one DC component in between the power source and my appliances, which has a current limiting factor, and I can't change that.
If I'd to parallel my appliances, I can only have certain amount of appliances in that circuit, say 8, whereas if I series them up and use a 48V DC rectifier (which I have plenty, and reasonably cheap), I would be able to double the appliances I can have in that circuit, 16.

 

[Sintra]

If you series connect 16 appliances from a 48V power source then each appliance will only have 3V.

 

[chng7]

If you series connect 16 appliances from a 48V power source then each appliance will only have 3V.

oops, sorry for missing out that information. I meant parallel 8 strings with 2x24Vdc per string.

Thanks for the heads up