Chopper Module (9): The Chopper regulates DC Bus voltage by sending power to the second circuit of the Dynamic Retarding Grid. This may occur while the truck is in propel mode, under retarding or during some fault conditions, as well as during engine load testing. The command and status signals for the Chopper is transmitted via fiber optic signals to an Interface Module.
DC Power Bus Capacitor (10): There is an external DC Power Bus Capacitor Assembly in addition to the capacitors contained within the Phase Modules and the Chopper Module. This capacitor filters the DC power coming from the rectifier, absorbs transient voltage spikes, and provides energy storage required for proper Inverter operation.