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Vaisala Thunderstorm Electric Field Mill EFM550

Thunderstorm Electric Field Mill EFM550 - thunderstorm tracking


      Vaisala Thunderstorm Electric Field Mill EFM550 integrates with Vaisala local-area, real-time lightning systems to monitor the development and dissipation of overhead lightning threats by measuring the local atmospheric electric field.  EFM550 data can be displayed using optional Vaisala ALARM Automated Lightning Alert Risk Management Software to show current electric field measurements numerically and graphically.

      The EFM550 integrates with local-area, real-time lightning information systems:
      • Vaisala Thunderstorm Lightning Warning System TWX300
      • Vaisala Thunderstorm Sensor TSS928 with Vaisala ALARM Automated Lightning Alert
      • Risk Management software
      Technical Specifications

       Technical Specifications

      Operational Specifications

      ​ ​
      ​+/- 5% of reading offset +/- 50 v/m
      ​Response Time ​1 Sec
      ​Signal Interface RS-232 (8 bit binary, 1200 baud)
      Sampling ​Fixed 2/sec message rate
      Range +/- 10 kV/m, max.

      Environmental Conditions

      ​Operating/Storage Temperature Range
      -10 °F to +115 °F
      (-23 °C to +46 °C)
      Humidity ​0% to 100%


      ​ Brushless; 25,000 hours MTBF
      ​Cable ​4-twisted pair, 24 AWG min


      ​Voltage ​100-240 VAC, 50-60 Hz; or 20-30 VDC
      Power Protection ​Multi-stage transient protection
      ​Power ​Consumption 2.3 watts


      • Hardware included for convenient mounting to a vertical pipe or
           flat mounting surface.
      • Minimum 6.0 in.(15.2 cm) clearance from bottom of junction box
           to mounting surface.
      • Maintain a minimum of 18.0 in.(45.7 cm) area clear between mill
           head and mounting surface.

      Support Services AND Standard Warranty

      ​Training, technical support, spare parts and service agreements
      are available for maintaining optimal sensor performance. Vaisala
      warrants all products manufactured by Vaisala to be free from
      defects in workmanship or material for one year from the date
      of delivery. Contact your Vaisala Sales Representative for specific
      support services and product warranty details. ​
      Related Services
      • Spare Parts 
      • Get rapid access to the spare parts you need to maximize the uptime of your equipment and ensure reliable and accurate operation. In addition to standard spare part delivery, we also offer an express service where parts are shipped within one business day.
      • Warranty 
      • All Vaisala products and services are covered by a 12-month warranty as standard, with selected products covered for up to 24 months. During this period you benefit from free repair or replacement of faulty equipment.
      • Repair Services 
      • Vaisala repair services include fault tracing and repair or replacement of failed components, as well as final testing to ensure your equipment is functioning properly. Repairs can be carried out on site or at one of our service centers.