Chris Radek wrote:
> Yay, I found my information...
>
> DC bus unfortunately is 100V so no common step-down transformer will
> do it.  The amps will do 14A continuous 30A peak, so you really need
> quite a few kVA especially if you are running the transformer under
> the rated voltage (6kVA + ?).
>
>   
Well, a step-down transformer wired for 480 : 120 but supplied with 240 
V input, will give 60 V RMS, which will provide 84 V DC.
Using a buck/boost transformer you could get somewhere around 84 V RMS 
to get 120 DC, or any other V you wanted.
Since the transformer can stand short surges, you wouldn't need 3 * 30 * 
100 = 9 KVA continuous rating.
In fact, that sounds like a major hazard, as the motors can only handle 
that for a couple seconds every few minutes.
Does this machine have SEM motors?  They are AWFULLY small, and have no 
special heat removal systems.
> If I remember right, the transformer I have waiting for this project
> is about 100lb.  There is no way it will fit in the existing cabinet.
> I do not remember for sure but I think it is a 415 to 120 step-down to
> give about 70V.
>   
Too bad it won't fit.  I got a Hammond toroid transformer, they have 
some up to 2 KVA or more.
Not junk-shop cheap, though.  About $180 each for a 1.5 KVA unit, I got 
one for Aram Kasparov's CNC box.
>   
>> Do you have any details on the servo amp enable and fault signals?  I 
>> have some info from the theory manual on the R2E3 (BOSS 8), but it is 
>> not QUITE enough detail to be sure about these.
>>     
>
> The fault output is open collector, normal low, goes open on fault.
>
>   
That should work nicely to drive the input to an optocoupler, putting 
the outputs in series for the e-stop chain.
> For the enable inputs: "contact closure or suitable active device
> capable of sinking a peak current of 20mA and having an offset or
> saturation characteristic of less than 0.6V ... between inhibit and
> signal common"
>   
OK, a 4-pole relay should do that nicely, or an opto-coupler would work, 
too.


Jon

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