sokbok
Member
- Location
- Kansas City
Howdy good people.
Attached is the nameplate of an older laser chiller.
We are going to run it on a 480D > 208Y transformer.
Our service is 208Y so we are feeding the transformer in reverse from how it was built.
The laser has ran successfully on this transformer for many years, we are just installing it in a new location.
I was not able to get much info on how it was wired previously.
I am confused about what Amp value to use for sizing both the 208 and 480 side.
As you can see from the nameplate, it is rated at 460V, which ultimatlely it may be ran close to based on its location and some voltage drop (perhaps I can adjust
transformer taps)
Anyway, I review article 440.12(B) (1) and am trying to save $ so evaluatling if it is continuous is also something to consider.
If I have a hard rule that every 3 hours the chiller must be turned off (I dont think many jobs will last longer then 45 mins) then I could further reduce the wire size to non-continuous.
Elsewhere on this forum I have been recommended to not run a neutral on either the 208 or 480 side of the XFMR (which could reduce OCPD requirements).
This is in fact how the transformer was wire previously (with no neutral on either side of XFMR).
Anyway....my plan is to size as non -continuous so 59 MCA x (460V x 1.732) = 47 kvA then use that to determine 208 side OCPD and wire = 47 KVA / 360.256 = 130A or (162 A continuous).Im worried about in rush current so Im thinking of sizing OCP and 208 wire at 175amps.
I am planning on sizing wire on 480 side at 55A or (70A continuous)
If I have no Neutral, do I need secondary OCPD after transformer, but before chiller?
I think because the primary OCPD is so far from the equipment, I will probably want a disconnect so YES, but does it need to be fused?
Im sorry for lots of questions and a similar post previously.
Has anyone had experience with laser chillers and if its best to just leave them on (therefore continuous)
I realize this is a complicated topic and I am here to learn.
thanks as always.
Attached is the nameplate of an older laser chiller.
We are going to run it on a 480D > 208Y transformer.
Our service is 208Y so we are feeding the transformer in reverse from how it was built.
The laser has ran successfully on this transformer for many years, we are just installing it in a new location.
I was not able to get much info on how it was wired previously.
I am confused about what Amp value to use for sizing both the 208 and 480 side.
As you can see from the nameplate, it is rated at 460V, which ultimatlely it may be ran close to based on its location and some voltage drop (perhaps I can adjust
transformer taps)
Anyway, I review article 440.12(B) (1) and am trying to save $ so evaluatling if it is continuous is also something to consider.
If I have a hard rule that every 3 hours the chiller must be turned off (I dont think many jobs will last longer then 45 mins) then I could further reduce the wire size to non-continuous.
Elsewhere on this forum I have been recommended to not run a neutral on either the 208 or 480 side of the XFMR (which could reduce OCPD requirements).
This is in fact how the transformer was wire previously (with no neutral on either side of XFMR).
Anyway....my plan is to size as non -continuous so 59 MCA x (460V x 1.732) = 47 kvA then use that to determine 208 side OCPD and wire = 47 KVA / 360.256 = 130A or (162 A continuous).Im worried about in rush current so Im thinking of sizing OCP and 208 wire at 175amps.
I am planning on sizing wire on 480 side at 55A or (70A continuous)
If I have no Neutral, do I need secondary OCPD after transformer, but before chiller?
I think because the primary OCPD is so far from the equipment, I will probably want a disconnect so YES, but does it need to be fused?
Im sorry for lots of questions and a similar post previously.
Has anyone had experience with laser chillers and if its best to just leave them on (therefore continuous)
I realize this is a complicated topic and I am here to learn.
thanks as always.