Hardware — Data acquisition: M-4839 accurately measure energy, frequency and power factor with VFDs and other high harmonic environments, and meets DoE requirements as noted in 10 CFR 429 and 431 and others. This is a Control Engineering 2017 Engineers’ Choice Awards Finalist.
WPM-4839 Wide-Band Power Meter is an accurate, economical energy measurement system for variable frequency drive applications.
The Department of Energy (DoE) issued changes to the measurement requirements for determining pump energy for equipment driven by electric variable frequency drives (VFDs) (10 CFR 429 and 431), and also issued a NOPR EERE-2014-BT-TP-0054 making similar revisions to the standards for electrically driven air-compressors. DoE is expected to expand its requirements across multiple categories of equipment.
The new standard requires accurate measurement of the input power up to at least the 40th harmonic of 60 Hz. In response, OSI has developed the WPM, an economical measurement system that allows for remote reading with simple commands in an open protocol that is available to all users:
It features…
- Accurate 0.25% of reading energy measurement up to the 40th harmonic of 60 Hz
- Selected CT’s for improved system accuracy
- Simple RS-232, RS-422, RS-485 or USB interfaces (used with a simple ASCII communication protocol).
The WPM was tested with 40th harmonic energy equal to 10% of the total energy with no significant deterioration in measurement accuracy. This was achieved by impressing 40th harmonic equal to 10% of the total on both the current and voltage signals.
In all cases, the WPM system exceeded the DoE requirements by a wide safety margin.
New DoE requirements can be readily and economically met with proven technology using open communication protocols.
Ohio Semitronics Inc., www.ohiosemitronics.com
