Nippon Chemi-Con KMZ 450V 820µF Capacitor Sits on the PFC Bus of a 2000W CRPS Server PSU
2026-10-13 · Compiled by Best IT Parts from public industry reporting
A teardown has identified a Nippon Chemi-Con (NCC) KMZ series aluminum electrolytic capacitor, rated 450V 820µF, sitting on the PFC high-voltage bus of a 2000W CRPS-185 server power supply, model FSP2000-20FM. The unit accepts 220-240V AC or 240V DC input and provides a 12V main output at 163.6A, reaching a maximum output of 2000W with 80 PLUS Platinum certification. The finding highlights the high-voltage bus capacitor as a critical component in high-density server power.
Internally the supply uses PFC, a phase-shifted full bridge and synchronous rectification. The front-end PFC corrects the input power factor and establishes a high-voltage DC bus; the phase-shifted full bridge then converts that bus down to the low-voltage side; synchronous rectification produces the 12V high-current rail. The 450V, 820µF capacitor is located between the PFC stage and the phase-shifted full bridge, directly across the high-voltage bus.
Its job is to filter the ripple that remains at the PFC output, store energy and buffer the transient power difference between the two conversion stages. Because the PFC stage needs time to answer fast server load swings, the capacitor can release stored charge for a short interval to reduce bus voltage excursions. The 820µF capacity offers substantial buffering for a 2000W platform, and the 450V rating covers the PFC bus with margin, including operation from 240V DC input. The standardized CRPS form factor supports modular deployment and redundant power in data center servers.
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Technical details are reproduced as reported. Verify specifications against the original source before design or procurement decisions.