Description
The Littelfuse 201A-9 is a 3-phase plug-in voltage monitoring relay designed to protect industrial motors and equipment operating on 190–480VAC systems. This advanced microcontroller-based device continuously monitors all three phases to detect harmful power conditions such as phase loss, phase reversal, undervoltage, overvoltage, and voltage unbalance. When an abnormal condition is detected, the relay output deactivates to prevent equipment damage and automatically restores operation once power returns to acceptable levels. Its compact plug-in design allows for easy installation in control panels and reliable integration into motor protection systems used in HVAC, pumps, compressors, and industrial automation applications.
Key Features:
- 3-phase plug-in voltage monitoring relay
- Operating range: 190–480VAC
- Detects phase loss, phase reversal, and voltage imbalance
- Overvoltage and undervoltage protection
- Microcontroller-based sensing for high accuracy
- Automatic reset when power conditions normalize
- Compact plug-in design for easy installation
- Ideal for motors, HVAC systems, and industrial equipment
