Any UPS/Inverter Experts Out There??

[Geno]

Model: FD5.3KVA
Manufacturer: Best Power Technology.

If the batteries on this thing ever die I can probably get it for free.
It was put into service around 12 years ago and has survived many lightning strikes in and around the building. There has been no maintenance on it in 10 years.

My main use would be to provide clean, constant voltage/frequency to my equipment/house.

If I hooked it up would It be more efficent to strap my ST head at 120 or 240?

It’s a big inverter but I don’t, at this time, have a good use for it.
Any comments on practical uses of any kind would be appreciated.

My main question is: Will my ST head provide clean enough power for it to even turn on. Newer UPS’s won’t turn on without good clean power.

The manual shows a 90% efficiency. Is clean power a good trade off to a 10% loss.

Its also got a 70 amp. break before make bypass switch. I can find a use for that!

Thanks, Geno

[mobile_bob]

as far as i am concerned that is one of the best ups systems out there, at least for the older ones.

pure sine wave, heavily constructed and well engineered.

90% efficiency aint bad in my books and the price is right.

bob g

[Tom]

Slight problem it says it is 208V which means 3 phase. It might not be the best choice unless it can be rewired for 240V.

Tom

[rgroves]

I bet this will sync up and work fine with ST output.  The waveform should be decent sine, and if you can regulate the rpm reasonably, the Hz will be close enough to 60 as well.  Every machine has its own limitations, but for example my Trace SW inverter claims it will sync to 57-63hz  and a fairly wide voltage range I can't recall at the moment. If you can find a manual for the UPS you might see how forgiving it is.

 Just make sure they aren't connected when you start and shut down the genset.

rg

[europachris]

Slight problem it says it is 208V which means 3 phase. It might not be the best choice unless it can be rewired for 240V.

Tom

Actually not, Tom.  208 isn't 3-phase in and of itself.  You can pull single phase 208 from 208 3-phase WYE connected power.  You have 120 from any one leg to ground single phase, 208 three phase WYE, and 208 single phase across any of the two hots.

I'm betting this UPS can be field-rewired for 120V or 240V.  It just came setup for 208.

Chris

[Geno]

Its internally selected for 208 single phase. It can be set up for 120 and 240 also.

Default frequency limits are ±3% and are selectable but to what limits the manual doesn't state. Thats nice.

Its good that my ST will probobly be OK. I have a client who spent good $ on a, computer grade genset for a big computer. The only way the UPS will turn on is if the generator has at least a 30% load. We have to hook up a 2000 watt load at the generator. Space heater or something. That was fun figuring out.

This thing also does a battery and inverter test at selectable intervals (24 hrs by default) I find it amazing that the batteries are any good at all. They are at least 10 years old and are probobly the originals. The final test report is from 1992! These people have been my client for years. I even installed this thing.

[rgroves]

Its internally selected for 208 single phase. It can be set up for 120 and 240 also.

Default frequency limits are ±3% and are selectable but to what limits the manual doesn't state. Thats nice.

Its good to my ST will probobly be OK. I have a client who spent good $ on a, computer grade genset for a big computer. The only way the UPS will turn on is if the generator has at least a 30% load. We have to hook up a 2000 watt load at the generator. Space heater or something. That was fun figuring out.

This thing also does a battery and inverter test at selectable intervals (24 hrs by default) I find it amazing that the batteries are any good at all. They are at least 10 years old and are probobly the originals. The final test report is from 1992! These people have been my client for years. I even installed this thing.

You could eventually wire some external terminals on the case, and use it as a well regulated, sinewave inverter with external batteries.  That would be a great combination with your ST.

[hotater]

This is the kind of thing I've been trying to figure out.  Several years ago I had a friend that salvaged a dozen big UPS units, batteries and all.  He couldn't find a buyer at any price in California and ended up selling them by the pound to a recycler.  The last time I talked with him he said there were stacks of these things sitting around, but going to get one would be expensive.....and without knowing what I'm doing I'd haul back a ton of useless junk.   

  It *seems* to me all it would take is to size the UPS for what loads you run, but I've never been able to calculate what's needed or how to do it.

[mjn]

Get it, and install some new batteries you won't regret it.

10 years ago, I ran a small data center with two Best Ferrups 18kva ups units.  It was absolutely great.

The only problem that I had with running on generator power was when the generator was not within spec for either voltage or frequency, the UPS would kick in.   One weekend when the power company had us shut off for major maintenance, we ran on generator for 48 hours.  Every time the building air conditioners kicked in, the UPS would switch to batteries for a minute or so.  After two days of this, the batteries ran dry and the UPS stopped working.

The nice thing about the Best Ferrups is that it has user settable limits for voltage and frequency.  I reset these to something more reasonable, and I never had the problem again.

[nutman]

Ive worked with those UPS models for years. Im quite sure that by now the batteries are shot. Notice on the keypad the buttons are multi-function. If you press the green display button, and then say, number one, it will display voltage in. You can also hook a laptop up to it using the terminal. Oh, it also has a discreet output to let you know if it is in inverter mode. Be careful when changing the batteries, DC make a beautiful blue arc.

Steve

[t19]

The sine wave out on these are wonderful because it uses a Fero Transformer (acts like a Capacitor) to clean up the square wave from the inverter.  Means it is heavy compared to other UPS that use digital systems to create a sine wave (SCRs)

the Transformer also allows for some limited ride through so that the inverter can come online.  This was the trick to get cheap older tech to compete with more expensive units.  But the real advantage is the clean sine wave from transformer.

I would buy one and put new batteries in.

as for the unit that died when the AC kicked in on Generator, I would check the set up, it should have had enough juice to top off the batteries when the AC was not starting.

I sold in another life a boat load of these things, had no service issues with them.

Wish I could find one for the house

[BruceM]

I wonder if anyone could suggest a source for schematics/circuit diagrams for these ferro UPS units.
I'm working on a ultra low EMI inverter design using intentionally slow switching of MOSFETs plus the old push-pull transformer approach and would LOVE to steal their sine wave shaping circuitry and perhaps try to get some of the hardware (ferro resonant transformer, chokes, etc) as well.

TIA
Bruce M

[t19]

Any square wave generating sine wave diagram would do.  the transformer hides a lot of sins

[BruceM]

Actually a square wave in will get you mostly a square wave out of a transformer. Likewise with a "modified" square wave. Plenty of these older type designs, some incorporate L-C filtering into the input (DC) side as well as the transformer as part of another LC, plus sometimes more on the output. Many of the designs also shorted the transformer primary for a few milliseconds at zero crossing time for a better waveform when driving inductive motor loads.

 It's not as simple as it seems, as in most things.

[t19]

Thats why its a Fero-Transformer.  It acts like a Capacitor to clean up the source