[kevb]

hi
im in the process of building a new control box for my CNC,
can some one please advise me about how many amps or VA, I need for the Toroidal Transformer,

its costing a fair bit of money to put this together so I want to get it right and I want to try and make this, so if I ever upgrade motors or change to another cnc,
this will be able to hopefully handle future upgrades,

I will be using PMDX boards

PMDX-134 mother board
PMDX-126 break out board
PMDX 137 Power Prep Module, 24v - 80 volt, 20 ampere
PMDX-107 spindle control

and 4 gecko G213V

so will be powering it with a + PMDX-137 power prep board
the output of the PMDX -137 is 24v - 80v 20 amps, the input 18v -56v,

to allow for an increase between AC and DC, I was thinking Toroidal Transformer of 50v, but don't know how many VA

the currant spec is,

all are nema 34,
1 motor (Y) is a Step Syn type 103-815-0741 DC 2.5v 4.6 amps 1.8 deg/step lot number 07626A IP43 Sanyo denki,
and 2motors (X & Z) are MAE SPA HY200 3424 0310 AL04, 3.1 amps P/N 946262- 00 A3957,

plus i will be adding a 4th rotary axis at a later date, to start will probably be a Chinese unit of EBay,

thanks in advance

Kevin

[mike_Kilroy]

Pm137 thing rated 20amp dc continuous. So 50vac gives 70vdc. So tofully utilize it for future too, u need 70*20=1400 watts. So input va is 1400va or 50vac and 28 amp ac. Pf is 1 so 1400watt=1400va.

[kevb]

thanks mike the largest 50v toroidal transformer i can find here in the UK is 500va 10amps, will this run the drives and motors i have now?
and can 2 50v toroidal transformers be wired up to give 50v but with 1000va 20 amps or what would you suggest i do


kevin


mods; sorry if i posted in the wrong section i would of thought this was more of a power supply question than a drive/motor one,

[mike_Kilroy]

Why not use a regular xfmr like most of us?

[ger21]

Your 3 motors will only need a maximum of about 7-7.5 amps, so 10 amps should be fine.
According to Gecko, the motors will never need more than 2/3 of theor rated current.

[mike_Kilroy]

I agree with ger21 of course that 500va would work.

But you said "so if I ever upgrade motors or change to another cnc, this will be able to hopefully handle future upgrades," and "plus i will be adding a 4th rotary axis at a later date."

I also wonder why you want to use a torroid rather than cheaper EI core ebay transformer? You want the 60x (possibly 600amp?) (rather than 15-20x (200amp?)) inrush randomly tripping your breaker? For what benefit? To save a few cubic inches of real estate?

[kevb]

hi
I was going to use one of these to start with

600W 48V 12.5A Power Supply PSU For CNC Stepper Motor Driver M542 M542H M860H | eBay

and after reading a few threads on a few different forums, most were using the toroidal transformers, so thought this was the way to go
price wise theres not a lot of difference £20 - £30, even with the hong kong suppliers

yes I was trying to make this control box as future proof as I can, or at most not so distant future proof, if thats possible, the cnc I have now has a 3ft x 3ft bed, im planning in a year or 2 to build a bigger 8ft x 4ft cnc with a large 4th rotary axis and rather than spend another £1000 on building another control box, I plan on using this one,

what's the best way to avoid inrush currant nuisance tripping the breakers ,
I get this occasionally with my lathe fitted with a 3ph inverter, its not every time I can go for months without tripping, and it can trip once or twive in a day then nothing for a while again,

could you post a few links to the type of psu you are meaning or would use

thanks for the replies guys

kevin

[Al_The_Man]

If possible I would stay away from SMPS (switching) supplies, regulated supplies are not needed for steppers and servo's and in the event of a failure they are usually tossed, so may be false economy in the end, one of the reasons I generally use a toroidal is the simplicity if you need to add an auxiliary winding or two for 24v/12v/5v supply etc.
A EI lamination transformers works as well just not as easy to modify.
Al.

[kevb]

thanks al

after searching for hours tonight i found this one 50v 20amps

Standard Range Toroidal Transformers: CM1000225: 1000VA 230v to 2x25v



kevin

[Fabianrplata]

Hi ger21
I have a hitachi seiki 4ne 600 lathe on my garage and I'm trying to find the right phase converter
Can you help me please ? I need to know How many amps this machine need.

[James Newton]

Best power supply: 4x 12 volt car batteries (in battery boxes with individual fuses) in series and a 48 volt "mobility cart" charger. Nearly unlimited peak amps, ZERO ripple, and the little charger can keep up with the /average/ current load. And the batteries don't have to be in tip top shape; you may be able to use old, weak (but chargeable) batteries or just smaller batteries. But do NOT skip the battery boxes and fusing. Very dangerous without that.
Slowing 69.16.243.61&c=1&t=42084.53415625

[Fabianrplata]

hi James
thanks you for the information,
i appreciate your help.