First central office I worked in had a huge- huge- huge- selenium rectifier stack. Plates about 1 foot square. It was in series with the battery. The battery also had 25 cells. The selenium rectifier would put in about a two volt drop under load.
When the power was out, the flooded cells would do their thing and when they got down to about 44 volts, a large contactor would short out the selenium rectifier and then the office had 46 volts for a few more hours. Other C.O.s had a special battery called a CEMF cell or counter electromotive force cell, that did the same thing as the selenium rectifier. Might be worth considering this idea again in mission critical applications. Perhaps solar off grid sites with no battery backup. From: Jason McKemie Sent: Saturday, March 05, 2016 1:35 AM To: [email protected] Subject: Re: [AFMUG] Eltek Rectifier Huh? I had an Emerson cabinet with pre-installed Loraine rectifier setup that had a LVD. I replaced it with an Eltek unit though, never used the LVD. On Friday, March 4, 2016, Eric Kuhnke <[email protected]> wrote: I've never seen a low voltage disconnect on telecom rectifier + float battery setups. It's assumed that for a backbone ISP POP that you will have an auto start generator. Or that you would rather drain your batteries all the way to dead, damaging them, but keeping the equipment online as long as possible (customer SLAs and hoping the grid power restores itself before the battery string is toast). On Mar 4, 2016 2:19 PM, "Gino Villarini" <javascript:_e(%7B%7D,'cvml','[email protected]');> wrote: thats weird, it leaves no space for lvd Sent from Outlook Mobile On Fri, Mar 4, 2016 at 2:16 PM -0800, <javascript:_e(%7B%7D,'cvml','[email protected]');> wrote: Frequently the rectifier and batts both go to the bus bar in the fuse or circuit breaker panel. Some folks feed both the rectifier and batts through a circuit breaker. If you do that you need to make sure the breaker can handle the max output of the rectifer or more. When there has been an extended power outage the batts will max out the rectifier current. From: Scott Vander Dussen Sent: Friday, March 4, 2016 1:26 PM To: javascript:_e(%7B%7D,'cvml','[email protected]'); Subject: [AFMUG] Eltek Rectifier Huh? Trying to figure these things out! I purchased and built an Eltek rectifier product using these products: CG1S-AUN-VC COMPACT POWER SHELF / REAR WIRE 200AMP MAX 48V UNIVERSAL OUTPUT POLARITY BC2000-A01-10VC 48V, SYSTEM CONTROLLER W/ ETHERNET, NEXTGENERATION, W/ CLEI V0750A-VC RECTIFIER, 840W, 53.5V, 15A, FAN COOLED (BOTTOM TO TOP) -INPUT: 90-264VAC It seems like this just takes AC power and gives me 48v DC out. I was expecting it would also attach to a battery array and provide charging of those batteries plus use their power source if grid power was lost. Am I totally wrong on that? I don’t see any method of connecting batteries to this power shelf :/ Noob out, Scott
