Gallery, Projects and General > How to's

How to Make a Power Supply

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Darren:
Chris, I think you mean you want 2.5A @ 37.5V?

But really if you read the instructions 24V output is ideal.

Yes this power supply would do that, but it's not the type I would use as you don't need the variable voltage facilities.

In all honesty at 33 quid each I would use theirs.

Any computor/laptop telephone, printer etc supply should do somewhere near 24V, some are 19V, they would do.

Just check the Amp outputs are high enough.

Bluechip:
Chris

Sent you a PM

dave

raynerd:
I see Darren! I`ve just looked at the pdf spec sheet and I took this from it:


--- Quote ---Setting the current for your stepper motors.
The formula VREF = Motor Current X 1.4 can be used to determine the Value for VREF
The most common current ratings are shown in a table below.
Motor Current
(A)
VREF Voltage
(V)
2.5 A - 3.5V
2.0 A - 2.8V
1.75 A - 2.5 V
1.5 A - 2.1 V
1.25 A - 1.8 V
1.0 A - 1.4 V
0.75 A - 1.05 V
0.5 A - 0.7 V
Note: It is normal to exceed the motors rated voltage by up to 20 times, for instance a
5V stepper motor run at 24 V would be perfectly expectable.
D Never exceed a motors rated current or the drive cards 30V DC Max. Doing so could
damage the motor and the stepper drive card.
--- End quote ---

How can a PS running 24V not blow a motor only requiring 3.75V ?

I think I understand the current a little more - is it saying that if the driver is rated 2.5A then that driver will draw 2.5A from the power supply, if your PS isn`t able to provide that current then your PS will blow as the components are drawing too much current from it - is that right? So in actual fact, to run one motor - it doesn`t matter as long as the PS is rated above 2.5A.

I still don`t get the voltage though, if the motor only runs at 3.75V how can I plug into the driver a 24v supply - surely it will blow the motor?

Chris

EDIT: the PS I have spare is a laptop 75W AC adaptor - DC output is 18-20V - 3.79A, would this be any use?

Darren:
What does it mean by vref?

That to me is in respect to the power supply setup and not the voltage output to the motor?

I could be wrong as I do not know the full facts,

In all honesty their power supply is a good price, you'd have a job to better it if you needed to buy all the components to make one yourself.

raynerd:
VREF = voltage reference.

I understand that their PS may be a good deal but I am interested to learn more about it myself and see if I could save money by using my own spare PS.

I appreciate your time and help.

Chris

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