Dear Editor:

Congratulations on the premier issue of Mission Critical. This is a much-needed specialized focus within the industry and one that turned out, even in just the first issue, to be insightful, informative, and helpful. Very much looking forward to future issues.

As the OEM suppliers of the Liebert FS flywheel system to Emerson Network Power, we are proud that author William Howerth made mention of the role that they play at the Jackson National Life data center that served as the cover story of the premier issue. One little correction, however: the data center uses six (not three) Liebert FS flywheels to deliver 22 seconds of ride-through to the generator at 100% UPS loading and 45 seconds at 50%. This isolates the parallel (redundant) UPS batteries from performing any duty since the flywheels solely bridge the genset startup gap (the flywheels have a higher discharge setpoint – 520 Vdc -- than that of the chemical batteries' 480 Vdc).

As with many users of the Liebert FS, Jackson National Life is now a repeat customer: We just fulfilled their purchase order for a second six-units. Once again, our congratulations to Mr. Heslin on development of Mission Critical.

Keith Field,

Vice-President of Marketing