The PMD Series Three-Phase Monitor Relays continuously monitor all voltages to
protect motors and equipment from expensive damage due to phase loss, phase
reversal, phase unbalance, undervoltage and overvoltage. These products detect
single phasing and unbalanced voltages regardless of any regenerative voltages.
Utilizing an advanced microprocessor-based design allows true RMS voltage
measurement with full wave monitoring. This provides a more accurate method
to measure the voltages, regardless of load type or wave shape, and results in
improved protection across more applications.
True RMS voltage measurement ensures accurate sensing in most generator and
other applications with non-sinusoidal wave forms, eliminating nuisance tripping.
Full wave monitoring provides a more accurate method to measure the voltages,
regardless of load type or wave shape, resulting in improved protection across
more applications.
Unlike similar three-phase monitor relays, the PMD Series will continue to function
even with a lost phase. They are the only line-powered units in their class to retain
fault indication and continuous monitoring of all voltages during a phase loss,
increasing the ease of troubleshooting and the level of protection.
The PMD Series is a true universal product, with three units that work on a wide
variety of adjustable line-line voltages to cover more global applications. Additional
knobs allow adjustment of the undervoltage trip point, trip delay, restart delay and
unbalance trip point. They utilize an enclosure for DIN-rail mounting that meets IEC
Standards.
Operation:
When the proper three-phase line voltage is applied to the unit and the phase
sequence (rotation) is correct, the relay is energized after the Restart Delay is
completed. Any one of five fault conditions will de-energize the relay after a delay.
As standard, re-energization is automatic upon correction of the fault condition.
Manual reset is available if an external momentary N.C. switch is connected to
terminals 4 & 5. A bi-color status LED indicates normal condition and also provides
specific fault indication to simplify troubleshooting.
Features
- Protects against phase loss, phase reversal, phase unbalance, undervoltage, overvoltage & rapid cycling
- Wide voltage ranges to cover more global applications
- True RMS voltage measurement ensures accurate sensing across more applications
- Retains fault indication and continues monitoring all voltages even with a lost phase
- Full fault indication on top of unit for easy troubleshooting
- Manual reset option works with external switch to reset the relay from outside the enclosure
- Compact 52.5mm wide enclosure for both DIN-rail or panel-mount
- 10A DPDT output contacts
