Many criterion AC-DC switch fashion ability supplies (most of Lambda’s products) specify a high voltage DC input make inwards add-on to the to a greater extent than mutual air-conditioning input make of 90-264VAC. We have many questions well-nigh how together with where to connect the DC input to an AC-DC furnish that is spec’d to travel off of DC likewise equally an air-conditioning inputs.
Where together with why is high voltage DC ability used? It turns out that many ability generation facilities provide a high voltage DC to ability the plant’s equipment rather than the regular 115VAC or 208VAC ability grid. This high voltage DC (typically 120 or 130-330VDC) tin last easily used amongst batteries to provide a secure root of ability rather than using expensive centralized or local UPS systems.
Now dorsum to the subject. The topology of many switch-mode ability supplies genuinely lends itself to performance from either air-conditioning or DC input. Important Note: Always banking concern jibe your ability supply’s Operations Manual or spec canvass to confirm that it is designed to travel from either an air-conditioning or DC input.
Referring to the simplified ability furnish schematic below:
When powered yesteryear an air-conditioning sine wave, during the showtime one-half bike the electrical flow flows from the Line final through the input filter together with charges capacitor C1 through diodes D1 together with D3. During the minute (negative) cycle, electrical flow flows from the Neutral final together with capacitor C1 is charged through diodes D2 together with D4.
When powered from a high voltage DC source, the polarity of the connectedness is non critical equally far equally the performance of the ability furnish is concerned. If the positive connectedness is made to the Line terminal, C1 is charged through diodes D1 together with D3. If the positive connectedness is made to the Neutral terminal, together with thence C1 is charged through diodes D2 together with D4.
An of import bill of caution to insert hither is well-nigh the protective fusing of the ability supply. Internally most ability supplies bring a fast acting air-conditioning rated fuse inwards serial amongst the Line terminal. It is recommended that a DC rated fuse last installed external to the ability supply. If 1 side of the high voltage DC osculation is connected to ground, together with thence the fuse is unremarkably positioned inwards serial amongst the “hot” side (the ungrounded side). It is recommended that you lot consult amongst your local security engineer to last sure.
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