21LM
The Model 21-LM 3-Phase Monitor provides essential protection for industrial systems. This manual reset device operates within a 95-120 VAC range, ensuring compatibility with common power configurations. It continuously monitors critical conditions including phase loss, phase reversal, over/under voltage, and voltage unbalance. Adjustable trip delay times, from 1 to 30 seconds, allow for precise system integration and nuisance trip avoidance. The robust SPDT 10A output contacts at 240VAC resistive facilitate reliable control and system integration. Its design supports both Wye and Delta systems, offering versatile application across various industrial setups. With a power consumption of 3.7W at 120V, it maintains efficiency. This monitor is engineered for consistent performance in demanding environments, contributing to operational stability and equipment longevity. Its UL Recognized status further assures adherence to established safety standards.
The Model 21 is a microcontroller-based universal 3-phase monitor for
protecting 3-phase motors from abnormal power conditions. It can detect
under voltage, over voltage, voltage unbalance, reverse phase, and
single-phasing even when regenerated voltage is present. The Model 21
includes adjustable trip and restart delays to prevent nuisance tripping
during power fluctuations and short cycling in compressor applications.
The LED status indicators and adjustment pots for Voltage Adjustment, %
Unbalance, Restart Delay and Trip Delay are mounted on the front of the
unit for easy access. Automatic or manual restart versions are
available. The Model 21 does not require a neutral connection and can be
used on either Wye or Delta systems. All versions of the Model 21 are
available with optional gold flashed silver contacts for low current applications..
Out of stock
Specifications
| Model Type | Manual Reset |
|---|---|
| Operating Voltage | 95-120 VAC |
| Power Consumption | 3.7W at 120V |
| Auto Ranges | No |
| Monitored Conditions | Phase Loss, Phase Reversal, Over/Under Voltage and Voltage Unbalance |
| Frequency | 50/60Hz |
| Type of Measurement | RMS |
| Under Voltage Trip | 90% ±1% (% of setpoint) |
| Under Voltage Reset | 93% ±1% (% of setpoint) |
| Over Voltage Trip | 110% ±1% (% of setpoint) |
| Over Voltage Reset | 107% ±1% (% of setpoint) |
| Voltage Unbalance Trip | 2-8%, adjustable (conforms to NEMA) |
| Voltage Unbalance Reset | Trip setting minus 0.7% |
| Trip Delay Time (Over, Under, & Unbalanced) | 1-30 sec., adjustable |
| Trip Delay Time (Single-Phasing Faults Unbalance > 15%) | 1 sec., fixed |
| Trip Delay Time (Reverse Phase) | 1 sec., fixed |
| Restart Delay | 1-500 sec., adjustable |
| Manual Reset Input | 5V open circuit/500µA short circuit |
| Output Contacts | SPDT 10A at 240VAC resistive |
| Operating Temperature | -20° to +140° F |
| Humidity Tolerance | 0-97% w/o condensation |
| Enclosure Material | Noryl plastic |
| Mounting | 8-Pin Socket (**sold separately) |
| Recommended Socket | 51x120 |
| Additional Options | /SG = Silver with Gold Flash Contacts |
| Agency Approval | UL Recognized (U.S. and Canada) (For use in a Pollution Degree 2 Environment) |
| Neutral Connection | Not required |
| System Compatibility | Wye or Delta systems |
| Recommended Fuse | 1A 600VAC |
| Warranty | 5-year Unconditional Warranty |
