UPS 750 Uninterruptible Power Supply Caterpillar

Illustration 1	g06057252
Extended Runtime Cabinet (Front) with door removed (1) Front Booster Module (2) Fuse switch (3) Fuse (750 VAC, 2000 Amp) (4) 500 MCM Lugs (12) (5) Positive bus shields (6) Positive cables (4) (7) BBI, EXRC, PWA (8) Capacitor (35 VDC, 1400 Amp Peak) (9) APC3 PWA (10) Main baffle (11) Inverter fan cover (12) Fuse (1000 VAC, 1250 Amp) (13) Negative Cables (4) (14) IGBT Common Bus (15) Capacitor 1200 VDC (16)

Illustration 2	g06057227
Extended Runtime Cabinet (left) with left outside and inside panels removed (16) Resistors, Enamel, 225 W (17) Booster Input Bus (Negative) (18) Booster Input Bus (Positive) (19) Inverter Plenum (20) Transformer, 1750 VA, 380-480/160, 230 V (21) Inductor, 912 A (4) (22) Cables (4) (23) DC Capacitor Module (24) Fan housing

Illustration 3	g06057270
Extended Runtime Cabinet (right) with right outside and inside panels removed (25) IGBT heatsink (utility and neutral) (26) Ground bus (27) Negative input/output bus (28) Inverter plenum (29) Positive cables (30) Positive input/output bus fuse (31) Capacitors, 2.2 μF (6) (32) Negative bus link (33) DC Capacitor booster shroud

Operation

1. The flywheel responds first and supports the load until depletion of the available energy storage.

2. The flywheel UPS walks-in the load to the battery system within 2 seconds to 3 seconds of the outage.

   Note: The walk-in eliminates step-load demand and voltage whiplash.

3. The battery system supports the load until power is restored or until the generator comes online.

4. The generator supports the load for as long as the generator can or needs to support.

5. Once power is restored, the flywheel UPS recharges in approximately 2 minutes. The Extended Battery System is also charged at this time.

The following sections describe an overview of the UPS equipped with the Extended Runtime Cabinet (EXRC).

UPS with EXRC Option and Batteries Start Sequence

1. If the grid (main) voltage is available and the key switch is turned to the "Normal" position, the unit charges the internal DC link. The charging is done by the activation of the input contactor and firing the line static switch with a phase control algorithm.

2. The DC link is charged via the line inductor, filter inductor, and the diodes in the utility inverter. If the Extended Runtime Cabinet (EXRC) is connected to the unit, the EXRC power electronics upper IGBT turns on until the secondary DC voltage (Battery side) reaches 2 V per cell. If the UPS DC Voltage reaches its nominal value, the flywheel start sequence begins as described in Step 3.

3. The flywheel excitation will be turned on and the flywheel inverter starts to turn the rotor as a synchronous motor. When the secondary EXRC DC voltage reaches 2 V per cell, the shunt trip contact and the under-voltage release contact in the EXRC cabinet are made inactive. The DC-disconnect switch can be manually closed at this time. After the DC-disconnect switch is closed, the UPS starts to charge the battery.

Data Characteristics

The battery of 240 cells has a float charge voltage of 2.25 Volts/Cell and a cutoff voltage of 1.67 Volts/Cell. The float voltage is controlled by the battery room temperature via an external sensor while the nominal voltage of 2.25 V/Cell gets linearly reduced for temperatures above 25° C (77° F).

Main Input Failure

If there is a main input failure, the line static switch will turn off immediately. The utility and flywheel inverter will reverse the operation and the input contact drops off. The battery charger also stops to charge the battery and enters an "Off" state.

The flywheel reverses to the generator function. The DC link is then changed with constant voltage via the flywheel inverter. The utility inverter converts the DC voltage to the 400-V three-phase AC voltage to power the connected loads. If the main input failure continues to 80% of the stored in energy in the flywheel, the unit will use flywheel energy only.

If the mains failure continues, the battery booster starts to boost the battery voltage into the DC link while the flywheel inverter stops to discharge the flywheel. The flywheel will coast down.

Main Power Return or Load Transferred to Generator

If the main power returns, the unit returns to "Online" operation mode. The output phase and frequency is synchronized to the input voltage and the input contactor closed again. The line static switch turns on and the unit moves the load from the battery to the input of the UPS. This happens on a programmable ramp rate with kW per second.

If equipped with a generator, a second parameter setup generates the new input power to adapt the system optimal to the generator. When all power is pushed to the new input source, the flywheel inverter will start to recharge the flywheel while the battery booster will turn off and wait for the signal to charge the battery again. This will be the case when the flywheel is fully charged back to the idle speed.

Operation Specifications (Extended Runtime Cabinet)

Environmental Requirements

• Operating ambient temperature range for cold start is at least 0° C (32° F) to 40° C (104° F)

• Ambient storage temperature range is at least −25° C (−13° F) to 70° C (158° F)

• Relative humidity limits are 5% to 95%, non-condensing

• Operating elevation limit is at least 914 m (3000 ft)

Note: For operation above 914.4 m (3000 ft), the ambient operating temperature should be reduced by no more than 1.2° C (34.2° F) for each 305 m (1000 ft) up to an elevation of 2134 m (7000 ft).

Note: Consult the battery manufacturer for environmental ratings of battery energy storage to be used with the EXRC.