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Use three-phase voltage sensors to detect primary system voltage on main and alternate sources for use in automatic transfer schemes. Voltage sensors detect voltage via the separable connector termination test point. The presence of system voltage is indicated via an electrically-isolated contact. E. O. Schweitzer Manufacturing makes and calibrates each voltage sensor as a complete custom solution for each application for delta- or wye-configured systems. Page two of the attached specification/installation sheets includes space for order-specific information to be filled out by the factory at the time of order.

  Learn more about the SEL Delta-Configured Voltage Sensor

  Learn more about the SEL Wye-Configured Voltage Sensor

• Isolated power supply: 24 VDC with a 50 mA maximum DC draw
• Drop-out voltage = 75% of system voltage
• Pull-in voltage = 90% of nominal system voltage
• Three sensors, one on each phase, connect to a single junction box
• Contacts on the delta sensor latch open when phase-to-phase system voltage on all three phases drops below 75%. The contacts latch closed when system voltage on three phases is above 90%.
• The wye sensor's contacts latch open when phase-to-ground system voltage on any phase drops below 75%. The contacts latch closed when system voltage on three phases is above 90%.