Power supply question

[jon]

Hi.
You will have to excuse my english. It´s a little rusty.

I am currently in the prosess of chosing the parts i am gonne order. Since i live in norway i would like to get it right the first time. But i don´t think electro is not my strong side.
I was thinking of ordering the package of 3axis driver with 3 200oz steppers from www.hobbycnc.com.
In norway we have 220V 60hz power. And in my hunt for transformers/trafos i stumbled upon a little trouble. Most manufactures only write that their trafo is ex:
"
Power: 20–600 VA
Primary voltage: 230 Vac
Frequency: 48–60 Hz
Isolation voltage: 4000 V

Power 600 VA
Voltage drop: 4 %
Load losses: 29–30 W
Idling losses: 3.2 W
Temperature rise: 55 °C
2×24 V~ Vac
"
That gives me no idea of how many Amps that is capable of.

If anybody could give me any hints on how this translates, or gives me any tips on other places that i can get a sufficent transformer capable for 220/230V primary that would be utterly helpful.

Or is this transated like this?
600Va/24V=25A?

Jonny

[Al_The_Man]

Originally Posted by jon Or is this transated like this? 600Va/24V=25A?

Roughly, yes. Here is Plitron site for sizing guide www.plitron.com
Full Wave Bridge
VAC = 0.8 x (VDC + 2)
IAC = 1.8 x IDC
These are Toroidal transformers which are more efficient than square lamination type, but more expensive.
Al.

[snaggletto]

Hello,
All transformers are rated in VA. VA = watts = Volts * Amps

"Or is this transated like this?
600Va/24V=25A?"

That is correct.

However, be aware that steppers of the size range you are talking won't use anywhere near 25A. At the site you linked to, they are recommending a 30V 10A or a 24V 10A transformer, that's 300VA and 240VA respectively.

Although more expensive, check out www.geckodrives.com and look at their stepper drives for a high performance stepper system. Good luck.

[jon]

Will i blow the drivers/steppers if the amp is too high?

[Al_The_Man]

Originally Posted by jon Will i blow the drivers/steppers if the amp is too high?

No the current is directly proportional to the load i.e. less load less current.
Al.

[jon]

Trying not to nag but:
Is a 35A 600V bridge diode and a Rectifier the same thing? I just want to make sure coulse i got a little confused coulse the recomendet transformer was this
"TRANSFORMER, FILAMENT & LV RECTIFIER, CHASSIS MT, 115V, 60HZ, 30.0VCT, 10A" So i wondered, Resifier? Is that build into that transformer? And must i have one since the one i thinking about ordering is a plain transformer.

Atleast now i have ordered the steppers and drivers, so i guess i will have something to do this summer

[Al_The_Man]

Bridge diode is 4 rectifiers connected in one package to provide full wave rectification, if you go to the plitron link and look at Tech Notes, you will see what you need and the configuration,
The rectifier is obtained separate to the Transformer.
Al.

[jon]

Thank you AL.
I think my major problem is my english :/

I thought the 4 diodes connected to remove the opposite ripples and coulse dc was called a recifier.

I think everything i need is in the package from hobbycnc.

Thanks for the answers.

[ESjaavik]

Originally Posted by jon In norway we have 220V 60hz power.

No, we have 240V 50Hz.

tips on other places that i can get a sufficent transformer capable for 220/230V

Try:
http://www.noratel.no/

or:
http://www.elfa.se
Then search for: 5613831 You may get a message in the main window, but just click on the link below the search window.

Buying a transformer from USA may not be so smart, as they have 60Hz and can use less iron in the core. So even if it comes with a 240V primary, it may heat up from core losses when used at 50Hz.

Or if you're in the inner Oslofjord area, mail me. I probably have what you need for your power supply.