18-120
The Model 18-120 3-Phase Monitor provides essential protection for industrial equipment. It continuously monitors for phase loss, low voltage, and phase reversal, safeguarding motors and other critical systems from operational anomalies. The unit incorporates an automatic reset function, minimizing downtime without manual intervention. Adjustable trip delays, ranging from 1 to 30 seconds, allow for precise response timing to transient conditions. Furthermore, a configurable restart delay, from 1 to 300 seconds, ensures controlled system re-engagement after a fault. This precise control over operational parameters contributes to enhanced system reliability and longevity, reducing maintenance requirements and improving overall process stability.
The Model 18 continuously monitors 3-phase power lines for abnormal
conditions. When properly adjusted, the Model 18 monitor will detect
phase loss on a loaded motor even when regenerated voltage is present.
This device consists of a microcontroller with a voltage and phase-angle
sensing circuit, driving an electromechanical relay. When correct
voltage and phase rotation are applied, the internal relay will
energize. A fault condition will de-energize the relay. When the fault
is corrected, the monitor will automatically reset. An adjustable
restart delay prevents short cycling in compressor applications and an
adjustable trip delay prevents nuisance tripping during power
fluctuations. The Model 18 does not require a neutral connection and
can be used with Wye or Delta systems. Voltage ranges are sufficiently
wide to allow for proper adjustment to existing conditions. Both FAULT
and NORM condition indicators are provided to aid in adjustment and
system trouble-shooting. The Model 18 is UL Recognized in the U.S. and
Canada and is available with optional gold flashed silver contacts for
low current applications.
Out of stock
Specifications
| Detection | Phase loss, low voltage, phase reversal |
|---|---|
| Reset Type | Automatic reset |
| Warranty | Five year unconditional warranty |
| Nominal AC (phase to phase) | 120VAC |
| Adjustment range | 85-120VAC |
| Frequency | 60Hz |
| Power consumption | 1.4W |
| Transient protection | 2500VAC for 10ms |
| Repeat accuracy | ± 0.1% of set point (fixed conditions) |
| Trip delay | 1-30 sec. |
| Restart Delay | 1-300 sec. |
| Dead band | Approximately 2% |
| Output contacts | SPDT 10 amps at 240VAC resistive |
| Expected relay life (Mechanical) | 10 million operations |
| Expected relay life (Electrical) | 100,000 operations at rated load |
| Operating temperature | -20° to +131° F |
| Humidity tolerance | 0-97% w/o condensation |
| Terminal Torque | 3.5 in. lbs. maximum |
| Wire Type | Stranded or solid 14-28 AWG, 1/terminal |
| Enclosure material | NORYL plastic |
| Mounting | DIN Rail or Surface Mount |
| Low Current Option | Models ordered with suffix '/SG' will have silver with gold flash contacts (SPDT 5 amps at 120VAC resistive) |
| Agency Approval | UL Recognized (U.S. and Canada) |
| Usage Environment | For use in a Pollution Degree 2 Environment |
| Dimension Tolerance | ± 0.06" |





