Newbie's Questions about Voltage

Hello,

iam new here (iam from Germany, sorry for this bad english).
i want to create a simple printer, but i need some information about voltage and so on.

my printer has the follow parts:

1 ramps 1.4 mainboard & ATMEGA 2560 (CH340 R3 MEGA 2560 R3 ATMEGA2560-16AU)

4 stepper motors & 4 stepper drivers
3 endstops
1 one nozzle with heater
1 lcd panel (optional)

iam getting a simple dc power supply, with 12v 5a
is this enough for the parts?

the stepper drivers says they output is (maximum 30v) & 2a

someone can explain this a bit more?

thanks for this great site.

greetings from germany
Franz

Hi Franz,

... related to the specs of your steppers, 5A should be enough, as the motor current is "averaged" to a lower level and not all motors are running synchronous.

By the way - wir haben auch ein Deutsches RepRap-Forum

- schaust du hier -- [reprap.org]

---

Viktor
--------
Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]

Wo finde ich das Deutsche Forum?

Aber bei meinen Geeetech A10 laufen eigentlich immer 3 gleichzeitig, X + Y (beim fahren eines Kreises z.b.) und dazu noch der Extruder. Wären dann ja 6A?

Die Heizdüse also der Heizblock, was verbraucht der so, dort stand beim Kauf nur 12v aber keine a?

Danke für die schnelle Antwort.

... mein Link geht direkt da hin ... ansonsten im "Haupt-Forum" weit unten bei "RepRap User Groups" auf den Ordner "Europe" gehen und da dann aufs "Deutschsprachige" ...

---

Viktor
--------
Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]

Hi Franz

I think a 5A PSU may be a little bit too small, I generally use a 30A 12vdc PSU - you can buy them very cheaply on Amazon. See attached

I have built three printers now, I have used two of these and an old PC AT PSU that I liberated from an old tower PC - works a treat

The main issue is going to be the extruder hot end and the heated bed, these are big current draws when heating up.



Regards

Rich

Hi Franz

Just a follow to make things a little clearer

Ohms law gives a formula for calculating Voltage, Current and Resistance V= IR

We know the voltage = 12v, the resistance will depend on what you buy and from that you can calc the current draw at peak load (which is what you must size your PSU against)

a J-head hot end heater is generally a 5.6 ohm resistor, so current(I) = 12/5.6 = 2.14A

Servos depend on what you buy, but again the construction is coils of wire that create electromagnetic fields that turn the motor, these coils have a stated resistance - something you should check before buying to ensure they are suitable for your project. Generally if you get the right beast the two main stepper boards have configurable current limits of approximately 1A or 2A, now depending on how hard you push them you can miss steps on the 1A variants, I swapped over to the DRV’s due to missing steps on my Y and extruder due to current, I also upgraded my Y servo, so I am pushing over an Amp per servo at peak load, so potentially I could be pulling at least 3A on a fast layer, the Z motors only run on layer changes.

As you can see I am already at over 5A on a mental calc - probably more.

Then there is the heated bed, generally 2 ohm , so that alone will want 6A

Then there the display, electronics, cooling fans........

At £15 for a 30A PSU or some time stripping down an old PC, far better than the frustration of failed prints or at worst a fire.

Regards

Rich