Re: Gecko 210 power supply ?

--- In CAD_CAM_EDM_DRO@yahoogroups.com, "rmtuckeruk" <rmtucker@l...>
wrote:

> I am in the process of building a power supply for my cnc router,
> Going to use Gecko 210 (3off).
> I am driving 3 off stepper motors 2.8v @ 4A/phase
> would i use a 45v transformer (45v*1.4=63v) or a 50v tansformer
> (50v*1.4=70v) the latter being exactly 25*motor rated voltage.Both
> are 1KVA.
> The motors in question are sanyo denki bi-polar motors (103h8222-
> 5141) rated at 5NM torque.
> I was going for the 50v tranformer but am i too close to the limit
> of the gecko or motor
> any advice would be appreciated.
>
> Regards
> Mark Tucker

Hi Mark,

let me take a stab at this. (corrections welcomed)

first off figure your total watts per stepper then rate your power
supply for that. I found my watts are a lot lower than my nameplate
amps.

Second, since you mentioned 4 amps a phase, you must use a heat sink
on the Gecko's. Finned heat sinks with a fan is all but required
when you get to 7 amps, but a sizeable aluminuim plate (1/4 inch
thick) could work as you are just pushing the 3 amp limit.

Lastly, go for the lower voltage. line fluctuatins will change your
line voltage at different times and although you are under 70 volts
by a few (when you deduct the rectfier voltage drop) you are still at
the bleading edge.

Mariss has mentioned more than once that a few units will work at
higher voltages, many will work at somewhat higher voltages, but all
will work when you keep the voltage under 70 volts. And if you have
read much of Mariss's stuff, you know he knows of what he speaks.

if you figure your line voltage can go from about 105 to about 130
depending on the utility on that particular day, many of us just
measure the incomming voltage and figure it is stable. if you get
115V and do all your calc's on that, then do them agian for 130, you
might get nervious.

Dave