Locating, Predicting, Preventing and Troubleshooting Power Quality Issues - Upto400 Hz. Higher power frequencies mean smaller and lighter transformers and motors - a critical concern in avionic and military transport applications where weight is a primary concern. The Fluke 437 Series II Power Quality and Energy Analyzer is the world's only Power Quality analyzer that can monetize the cost of energy waste due to poor power quality and is ideal for characterizing power quality, conducting load studies and capturing hard-to-find voltage events over a user-defined period of time. Designed for capturing power quality measurements in avionic and military systems, Fluke 437 Series II is the must-have 400 Hz quality analyzer.