ACCUMULATOR GP-HYDRAULIC 0874454 - Caterpillar

Cabinet Description
The Inverter Cabinet is a 42-inch wide cabinet that houses the inverter assembly components. The inverter assembly is two 600KVA 3-phase inverters that operate in parallel. Each 3-phase inverter contains three Inverter Modules. There are a total of six Inverter Modules that make up the entire inverter assembly.The complete inverter assembly includes the following components:
Heatsinks
Insulated Gate Bipolar Transistors
Driver and control boards
A positive DC bus fuse
A negative DC bus fuse
Low inductance bus bars interconnecting the Insulated Gate Bipolar Transistors
A DC capacitor bank and an associated current transformer to monitor the currentThe Inverter Modules are mounted vertically, three on each side of the cabinet, to form the inverter. The Inverter Modules that are mounted on the right side of the cabinet are turned 180 degrees from the Inverter Modules that are mounted on the left side of the cabinet. In both cases, the heatsinks are oriented toward the centerline of the Inverter Cabinet.A fan plenum with five fans provides the necessary cooling. Air is drawn in from the front, forced into the plenum at high velocity, into the heatsink fins and exhaust from the top of the cabinet.Each Inverter Module is controlled by the APC2 Board in the Controls Cabinet. The control signal drives the Insulated Gate Bipolar Transistors from the DGL board on each Inverter Module. The pulse-width modulated sine wave is filtered by the inductors and capacitors and yields smooth sine wave output voltage.Inverter Control
The APC2 switches the Insulated Gate Bipolar Transistors to form a 3-phase pulse width modulated sine wave, which is fed into the filter inductors and capacitors to produce a clean sine wave output.The voltage source of the Uninterruptible Power Supply (UPS) is run in parallel and at the same frequency as the input source. The amplitude of the voltage source of the UPS is controlled to a constant nominal output voltage. The result is a constant UPS output voltage.The phase angle of the inverter voltage closely matches the phase angle of the input voltage and is varied by a small amount to keep the DC bus at constant voltage.If the inverter voltage phase angle leads the input, power flows out of the DC bus. If the inverter voltage phase angle lags the input, power flows into the DC bus.Online Mode
When the UPS is online, the inverter is controlled to perform the following tasks:
Provide the load with a constant voltage. Even though the UPS input voltage may vary, the output voltage of the UPS remains constant.
The inverter of the UPS draws power from the input source in order to keep this DC bus at constant voltage. When the Flywheel Cabinets are not discharging, the cabinets draw small amounts of power from this DC bus in order to keep the flywheels at speed.
Supply the reactive and harmonic currents that are required by the load to maintain low input current Total Harmonic Distortion.When the UPS detects an input voltage problem and goes into discharge, the load of the UPS draws power from the DC bus through