| |
| Illustration 1 | g03693072 |
|
Flywheel inverter module (1) Handle for the flywheel gate driver board (2) Flywheel gate driver board | |
The flywheel inverter assembly is located in the upper part of the flywheel cabinet, on the right side. During discharge, the flywheel inverter provides the following:
- Rectifies the three-phase AC signals from the armature windings
- Maintains the voltages for the DC bus
During discharge, the flywheel inverter assembly converts the 3-phase AC voltage from the flywheels to keep the DC bus energized. The regulated DC voltage is used by the utility inverter. The utility inverter converts the regulated DC voltage back to AC voltage to supply power for the customer load. The flywheel inverter assembly is made up of three inverter modules. Each inverter module contains an insulated gate bipolar transistor (IGBT) module, DC capacitors, and a heat sink.
The flywheel gate driver board needs to be removed in order to gain access to the flywheel inverter module. The phase 1 module must be removed in order to access the phase 2 module. In order to access the phase 3 module, the phase 1 module and the phase 2 module must be removed.
- Refer to Systems Operation, Test and Adjust, UENR4695, "Internal Component Pre-Removal Steps (FPU)". Perform the internal component pre-removal procedure to shut down the system and to gain access to internal components.
Note: The flywheel cabinet must be de-energized before removal steps can be performed.
The flywheel inverter module is heavy. The module weights more than
25 kg (56 lb) . Exercise caution when removing the last bolt so the assembly does not fall and damage components or personnel. - Ensure that the DC capacitor module has been removed "BEFORE" removing the inverter module. Refer to Systems Operation, Test and Adjust, UENR4695, "DC Capacitor Module" removal and installation instructions.
- Disconnect the FGD top and bottom cable from the right side of the module.
- Remove J1, J2 and J3 from the module.
- Remove the six mounting bolts that connect the bottom of the module to the flywheel cabinet frame.
- Remove the eight mounting bolts that connect the top of the DC capacitor module to the flywheel cabinet frame.
- Use the DC capacitor/inverter lifting tool to slide the DC capacitor/inverter module forward and down to remove.
For instructions for using the lifting tool, refer to Systems Operation, Test and Adjust, UENR4695, "DC Capacitor Module" removal and installation instructions.
- Attach the DC capacitor/inverter module lifting device block and tackle to the new module.
- Install the new DC capacitor/inverter module.
- Install the six mounting bolts that connect the bottom of the DC capacitor/inverter to the flywheel cabinet frame.
- Install the eight mounting bolts connecting top of module to flywheel cabinet frame.
- Connect J1, J2 and J3 to the DC capacitor/inverter module.
- Connect the top FGD and bottom FGD cables to the right side of the module.
Note: The correct order to install the DC capacitor/inverter module is: phase 3, phase 2, and then phase 1. The phase 3 module must be installed before installing the phase 2 module.
- Check workmanship and ensure that the installation is completed.
- Remove the lifting tool and stow properly.
- Close and lock the cabinet doors.
- Energize the system according to the system start-up procedures.