Ve6fi Amateur Radio

 

The UPS Story

At the new location of the ve6fi amateur radio station we decided that we would not deal with the power companies or gas companies and as such we would provide our own source of power. It may not be economical but we would be independent.

We started educating ourselves on solar panels and windmills. We decided that we would go with solar energy. But how many solar panels, where do we mount them and how do we convert the power to AC power to energize our radios, amplifiers and rotators.

Well that is where the UPS come into play. An UPS is an Uninterruptible Power Supply. It converts the DC (Direct current) voltage off of the batteries to alternating current. We decided we had to figure out what we where going to use for an UPS before we purchased the solar panels.

We looked at commercial UPS’s and wondered what voltages we should use. The commercial ones where a bit expensive – well into two to three thousand dollars range for a 3 kVA system. Most seem to be at a lower voltage, which would mean heavier wiring. Anyway, we did a rough design to establish what capacity we needed. Off we went to see what was available at the Government Auction. Well a public auction was taken place the next day and they had a 40 kW UPS in the auction sale. We had a quick look but did not really have much time to investigate the unit that was lying outside at the government location. There were three bays of equipment with some pretty big wires and a bay and half of batteries.

We bid on the whole package and for a few hundred dollars we had ourselves a 40 kW UPS system. It was a lot larger than what we needed but the price was right. We got the big yellow truck and hauled it to our radio site. Well it was about a week later that we started looking at the drawings to figure out what did we really get – or maybe what we did not get!

We were looking for the four 10KW inverters which are the heart of the system. Well we found out where they were supposed to be mounted but all there was at that location was four blank panels. They must have kept them as spare for another unit or else they had failed.

Then we thought that maybe we should get a smaller one to give us temporary power until we found a correct one. At the next sale there was a smaller Toshiba UPS rated at 3.3 KVA. We bid on it and did get it for a few hundred dollars. It was a lot smaller in size than the 40 KVA unit and it had a set of batteries and ran with 215 volts DC input and had an output of 240/120 volts AC. I thought I would test it out at home before I would install it at the ve6fi site.

I plugged the Toshiba into 240 volts and it came to life so that was a good sign. I was able to go through the menus and all seemed OK. I left the batteries charge for a day as the skimpy manual suggested. Then I hooked a couple of 1.5 kW heaters on the output and pulled the input plug out. There was nothing - no heat - no noisy - nothing! I took the three batteries out and checked them individually and all was OK. I thought I would have a look inside and removed the hood. There sure are a lot of electronic boards in there and of course they do not supply any schematics. They just say, ’Call our technical staff and arrange for an appointment’! I checked around a bit more and found that there was no 215 volts DC although each individual battery checked out OK. I dug around some more and found that one of the battery packs was wired incorrectly and resulted in no series connections to provide the 215 volts. It really was a fault from the battery factory. I do not think that it would ever have worked when the power failed for the Government boys!

OK so we were making progress. I pulled the 240 AC input plug and it kept on providing power to the heaters – good stuff. I shut it off and decided to try to cold start it (that is without input AC power). Nothing doing – this unit was not designed to cold start. It was designed to be on line and when the input AC failed it would take over. This was not suitable for us at ve6fi since we are not connected to the grid at all and would have to start the standby generator so we could start the UPS. No deal, we could not use this UPS.

There was another Government auction coming up and there were two 8 KVA UPS up for sale. They did not have any batteries in them but the book said they could cold start and used a + 192 volt rail and a – 192 volt rail. Gee there were two of them so we could have a spare. So I went to the sale and noticed that they had piled the two APC UPS on a skid with about three other electronic type boxes and were selling the whole skid. Now one has to be careful at these auctions for if the auctioneer does not get a first bid too quickly he will pile a whole bunch of other stuff in the package. The high bidder then would get what they want but included would be a whole truckload of stuff they do not want. I threw in a bid and we were on our way. Gee someone was bidding against me. Since we were around the $50.00 range I thought I would smoke him out. I kept bidding and he dropped out at $125 so I bought the whole skid full of stuff. My bidding opposition was interested in one box that was part of the package, which I did not want anyway. So we both went away happy.

I wondered if this thing would work. I did not have a 192 volt set of batteries at home so I installed the UPS in its final location at the ve6fi site feeling confident that it would work. I hooked the two battery voltages to it and flipped on the switch - A little buzzing, a flash of the LED’s and then nothing. I went home and continued reading and searching the Internet. Oh, you have to push the ON button for five seconds. The next time I went out to VE6fi I pressed the button and the UPS came to life – Good stuff I said to myself.

I checked the voltage and frequency and it was 208 volts AC at 50 Hz. Gee who uses 50 Hz in Alberta! I read some more and it said you could change the settings in software to 240 volts and 60 Hz. No problem I said and plugged a regular serial cable into the back port of the UPS where it said ‘serial port’. As soon as I plugged it into my laptop the UPS stopped and all the buzzers were buzzing. I read some more and found out that they said, ‘Use our special serial cable, which you can purchase from us for $79.95’. This sounded like a good deal so I found out the pin-out and made my own. OK so now I could run a terminal program to set the voltage and frequency but wait. The computer said, ‘Password and User name please’. Gee I started wondering what the Government would have set these two words too! I put in the factory default and we were connected.

So now we had 240 volts and 60 Hz. The output port had four terminals namely 240, 240, N and ground so I wired it into my AC distribution panel, which had some 120-volt receptacles already tied on. OK so far; so just to be safe I measured the voltage across the 120 volt receptacle – Gee it was 240 volts instead of the required 120 volts. This UPS was a 240 volt output only with no Neutral and no 120 volts to neutral. This meant that I needed a 10 KVA transformer to convert the 240 volt two wire system to a 240/120 volt three wire system.

Where do I find such a transformer capable of that Kva? Well I did not have to look too far to find one. I had built an 8 KVA battery charger to charge the batteries from a generator so I already had the components. I rewired the transformer and all of a sudden I had 240/120 volts available and all was well with the voltages. I threw 6 kW of heaters at 240 volts onto the UPS and voltages were all OK and no heat from the transformers. At the moment we have 8 KVA of capacity and we have a spare 8KVA UPS. Now the UPS has been on for over a month and no alarms or surprises.

So we are climbing up the UPS learning curve.

Denis Ve6aq

April 2013

                                                                Back