The PMD Series Phase Monitor Relays utilize a
microprocessor-based design to provide protection against phase loss, phase
reversal, phase unbalance, undervoltage and overvoltage. The PMDU is a
universal voltage product that works on any three-phase system voltage from
208-480V (separate 120V & 575V versions are available). These devices are
designed to be compatible with most Wye or Delta systems with no connection to
Neutral required. PMD Series products protect against unbalanced voltages or
single phasing regardless of any regenerative voltages.
The relay is
energized when the phase sequence and all voltages are correct. Any one of five
fault conditions will de-energize the relay. As standard, reenergization is
automatic upon correction of the fault condition. Manual reset is available if
a momentary N.C. switch is wired to the appropriate terminals. A multicolor LED
indicates normal condition and also provides specific fault indication to
simplify troubleshooting.
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The PMD
Series offers a variety of user-adjustable settings. The percent phase
unbalance is adjustable from 2-10%, and also has a ..Disable.. setting for
those applications where poor voltage conditions could cause nuisance tripping.
The undervoltage drop-out can be set at 80-95% of operating voltage
(overvoltage setting is fixed at 110% of nominal). The adjustable time delay
drop-out on undervoltage (0.1-20 seconds) eliminates nuisance tripping caused
by momentary voltage fluctuations. There is also an adjustable time delay
(1-300 seconds) on both power up and restart after a fault has been
cleared. |
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Features:
- Universal voltage range of 208- 480V on PMDU provides the
flexibility to cover a variety of applications with one unit
- Protects against phase loss, phase reversal, phase
unbalance, undervoltage and overvoltage
- Variety of user-selectable and adjustable settings for
the ultimate in three-phase protection
- Automatic & Manual Reset in Same Unit
- Multi-Color LED indicates normal condition and provides
specific fault indication to simplify troubleshooting
- 45mm DIN-style surface-mount case
- 10A SPDT & SPNC output contacts
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Part Number |
Protects Against |
Nominal Voltage (50/60
Hz) Phase to Phase (Line to Line) |
Wiring |
PMD120 |
Phase Loss, Phase Reversal, Phase Unbalance,
Undervoltage & Undervoltage |
120V |
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PMDU |
Phase Loss, Phase Reversal, Phase Unbalance,
Undervoltage & Undervoltage |
208-480V |
PMD600 |
Phase Loss, Phase Reversal, Phase Unbalance,
Undervoltage & Undervoltage |
575V |
Phase Loss: |
Unit trips on loss of any Phase A, B or C. |
Phase Reversal: |
Unit trips if rotation (sequence) of the three phases is
anything other than A-B-C. |
Undervoltage: |
Adjustable from 80-95% of nominal voltage. Unit trips when
the average of all three lines is less than the adjusted set point for a period
longer than the adjustable time delay drop-out. |
Overvoltage: |
Fixed at 110% of nominal voltage. Unit trips when the average
of all three lines is greater than the fixed set point for a period longer than
the time delay drop-out. |
Phase Unbalance: |
Adjustable from 2 - 10% unbalance. Unit trips when any one of
the three lines deviates from the average of all three lines by more than the
adjusted set point . There is also a ..Disable.. setting adjustment that will
turn off the Phase Unbalance Protection if nuisance tripping is a problem. |
Output Contacts: |
10A SPDT & SPNC @ 240V AC/30VDC, 1/2HP @ 120/240V AC
(N.O.), 1/3HP @ 120/240V AC (N.C.) |
Life: |
Mechanical: 10,000,000 operations, Full Load: 100,000
operations |
Response Times: |
Power Up & Restart After Fault: 1 - 300 seconds
adjustable Phase Loss & Reversal 100ms fixed Phase Unbalance 2
seconds fixed Undervoltage 0.1 - 20 seconds adjustable Overvoltage
Fixed Time Based on Inverse Time Curve |
Hysteresis: |
2-3% |
Load (Burden): |
Less than 3VA |
Temperature: |
-28° to 65°C (-18° to 149°F) |
Mounting: |
Does not require a socket. Can either be mounted directly on
35mm DIN track with no additional parts or to a back-panel with Panel Mounting
Kit (supplied) & two screws |
Reset: |
As standard, reset is automatic upon correction of fault.
When a momentary-contact N.C. switch is wired across the Manual Reset terminals
(M1 & M2), the unit switches to manual reset mode and remote manual reset
is available. |
LED Status |
Inicator |
Green Steady |
Normal / Relay ON |
Green Flashing |
Power Up / Restart Delay |
Red Steady |
Unbalance |
Red Flashing |
Undervoltage / Overvoltage |
Amber Steady |
Reversal |
Amber Flashing |
Loss |
Green / Red Alternating |
Undervoltage / Overvoltage Trip Pending |
Red / Amber Alternating |
Nominal Voltage Set Error |