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G8MNY  > TECH     30.11.23 09:51z 123 Lines 5931 Bytes #22 (0) @ WW
BID : 61390_GB7CIP
Subj: APC 1500 UPS
Sent: 231130/0949Z @:GB7CIP.#32.GBR.EURO #:61390 [Caterham Surrey GBR]

By G8MNY                                         (New Dec 16)
(8 Bit ASCII graphics use code page 437 or 850, Terminal Font)

This is some info I have found out on this American Power Conversion UPS.
(Uninterruptable Power Supply) I is much same as the "APC Smart 900" but
does more power as well as a step up or down mains conditioning feature & is
fan cooled.

SCHEMATIC                   v       v                        v
   ┌────┐┌─────┐┌──────┐ ┌──┴──┐┌───┴────┐_┌───────────┐ ┌───┴───┐  ┌───┐
In>┤12A ├┤Spike├┤Mains ├┬┤ON OR├┤NORMAL/ ├─┤   Large   ├┬┤ Smpsu ├─┬┤Bat├>
IEC│Trip││Clamp││Filter│││ FAIL││UP/ DOWN├─┤Transformer││└───────┘ ││Mon│
   └────┘└─────┘└──────┘│└─────┘└──────┬─┘ └───────────┘│┌────────┐│└───┘
                        │┌──────┐      │┌───────┐       └┤SM Sine ├┴<Batteries
                        └┤In Mon├>     ├┤Out Mon├>       │Inverter│
         v               └──────┘      │└───────┘        └───────┬┘
Out  ┌───┴───┐ ┌──────────┐ ┌─────┐    │       ┌─────────────┐   ^
4x<──┤LOAD ON├─┤Filter Cap├─┤I Mon├────┘      >┤uProc Control├>
IEC  └───────┘ └──────────┘ └─────┘            └─────────────┘

The control sorts out what is the required state for the 3 relays (CAPITALS)
from the various monitoring function inputs. It also predicts battery life.

It is a switched UPS system, which means there is a very short break (10ms?) in
the output when the supply goes out of limits (fails) & the inverter cuts in.

The 24V volt inverter uses a powerful bridged Class D 16 FET amp at many kHz.

   │║▓█▓║│         Phase 1     +24V HF pulses
   │║▓█▓║│                     fed via the 2 
~~~~~~~~~~~~~~~~~~~            FET outputs to
           │║▓█▓║│             each side of
           │║▓█▓║│ Phase 2     the transformer.
    /   \                These pulses do not get through
   |     |               the Transfromer with mains capacitor
  |       |       |      so the resultant filtered output is
           |     |       a rounded mean of those needle
            \   /        pulses to make a 50Hz sine wave.
There are several feedback loops that control the output.
1) The 50Hz is locked in phase to the incoming supply when it is present so
   there is less of a voltage jump on changeover.
2) Output Voltage feedback ensures regulated voltage.
3) Over current alarms & then kills the inverter, protecting it from damage.

These are 2x 17AH Batteries, accessed from the pull of front pannel. As with
most UPSs of this sort they are literally CAINED to get the performance! So
don't expect them to last long. On full load discharge in something like 4 min
the batteries are spent, & possibly dammaged! On light loads 1 hr is possable.
This UPS has an earthed battery system, there is no connection to the mains as
same are. So it is safe to add external large fused batteries. eg. 2 120 lorry
batts fused @ 60A beeteen their 12V Link.
There is DC Safety link on the rear panel to disconnect the inverter.

              │   []     []reduce     .˙.                  []   │
              │   []                 ( 1 )                 []   │
              │   []     [] normal    test                 []   │
              │   []                                       []   │
              │   []     []     []    .1.    []            []   │
              │   []    boost   On   ( 0 ) Smart Replace   []   │
              │  Load         Battery '˙'  Boost Battery Battery│
             The green mains ON LINE LED will be flashing in test node (if
             there is mains present), & the yellow ON BATTERY LED will be on.
             After the 10 second test it will switch back to the mains if it
             is OK, & the green mains ON LINE LED stays on & out goes the
             yellow ON BATTERY LED.

             If mains is just goes a bit to low the yellow SMART BOOST LED
             lights after a second of inverter fill in power.

             If the battery will not accept a charge the red REPLACE BATTERY
             LED is lit up.

Bargraphs:   The battery status bargraph indicates the battery voltage & is a
             good indication of the condition.

             The mains load bargraph lights up as the output loading is
             increased to the maximum 1500W load. (200W/0.8A per LED)

Alarms:      The beeper sounds 4 beeps every 30 seconds after mains fails
             (1/30 seconds initial delay option SW3).

             And when the battery is too low (2min/5min warning) rapid pulse.

             And if the load is excessive.

Mains Fail:  As options set near instant changeover to synchronised inverter on
             failure, e.g. under/over volts, under/over frequency.

Mains Reset: After 5 seconds of good mains, near instant change back to mains.

Power off:   Just throw the rear ENABLE switch to off. This disconnects the
             output & stops all battery drain.
             Pressing the (0) button only works with no mains, otherwise you
             get a briefly interrupts the output only (dirty changeover).

Charging:    If just charging is needed then leave the rear ENABLE switch on
             without pressing (1) test button.

As with most things with uProc control that can go wrong & a full power off
with battery disconnection may be needed in the worst case. (e.g. before you
buy a new set of batteries!) Then do a fresh power up on recharged batteries
with a 30% mains load to recalibrate the uProc's battery predictions during the
self test.

See my buls on "APC Smart 900","META HF Melenium 810 UPS", "Lead Acid
Batteries", "Constant Voltage Transforemers" & "Mains Power Protector".

Why don't U send an interesting bul?

73 De John, G8MNY @ GB7CIP

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