Littelfuse 201A-9 Monitor
The Littelfuse 201A-9 Monitor is a professional-grade 3-phase plug-in voltage monitor engineered to safeguard motors from fluctuating power conditions. This auto-ranging unit operates across 190-480VAC at 50/60Hz, utilizing a high-speed microcontroller-based voltage sensing circuit to detect imbalances before they lead to winding failure. Unlike standard models, the 201A-9 includes specialized high voltage detection, tripping the 10A output relay if line voltage exceeds 110% of the setpoint. The compact 8-pin octal base design ensures a seamless motor protection relay installation into existing control panels using a standard 35mm DIN rail socket. Integrated LED diagnostics provide immediate visual feedback, distinguishing between phase reversal, low voltage, and unbalance faults. This unit is essential for protecting 3-phase compressors, pumps, and fan motors from single-phasing and harmful transients, reducing unbudgeted downtime for mechanical contractors and facility managers.
Key Benefits- Universal Compatibility: Auto-sensing dual-range logic (200V and 400V) fits a wide variety of HVACR applications without manual jumper settings.
- Advanced Protection: Specific high voltage trip capability prevents insulation breakdown during surge events or utility overvoltage.
- Contractor-Friendly Diagnostics: High-visibility LED flashes specific color patterns to identify the exact cause of a trip, shortening troubleshooting time.
- Robust Build: Solid-state design with phase loss protection ensures reliability in demanding industrial environments.
How do I set the line voltage on the 201A-9?
Rotate the nominal voltage adjustment dial to match your system’s nameplate line-to-line voltage. The internal logic will automatically scale the trip points based on this setting.
What socket is required for a UL-Listed installation?
For a compliant installation, use an 8-pin OT08-PC or RB08-PC octal socket, which supports 35mm DIN rail or surface mounting.
Will this monitor protect against a phase reversal?
Yes, the unit detects incorrect phase sequence upon power-up and will prevent the motor starter from energizing, protecting equipment from backward rotation.
Disclaimer: While we strive for 100% accuracy, product data and specifications are subject to change. Please contact our team to confirm compatibility or technical details before purchasing.
Littelfuse 201A-9 Monitor
The Littelfuse 201A-9 Monitor is a professional-grade 3-phase plug-in voltage monitor engineered to safeguard motors from fluctuating power conditions. This auto-ranging unit operates across 190-480VAC at 50/60Hz, utilizing a high-speed microcontroller-based voltage sensing circuit to detect imbalances before they lead to winding failure. Unlike standard models, the 201A-9 includes specialized high voltage detection, tripping the 10A output relay if line voltage exceeds 110% of the setpoint. The compact 8-pin octal base design ensures a seamless motor protection relay installation into existing control panels using a standard 35mm DIN rail socket. Integrated LED diagnostics provide immediate visual feedback, distinguishing between phase reversal, low voltage, and unbalance faults. This unit is essential for protecting 3-phase compressors, pumps, and fan motors from single-phasing and harmful transients, reducing unbudgeted downtime for mechanical contractors and facility managers.
Key Benefits- Universal Compatibility: Auto-sensing dual-range logic (200V and 400V) fits a wide variety of HVACR applications without manual jumper settings.
- Advanced Protection: Specific high voltage trip capability prevents insulation breakdown during surge events or utility overvoltage.
- Contractor-Friendly Diagnostics: High-visibility LED flashes specific color patterns to identify the exact cause of a trip, shortening troubleshooting time.
- Robust Build: Solid-state design with phase loss protection ensures reliability in demanding industrial environments.
How do I set the line voltage on the 201A-9?
Rotate the nominal voltage adjustment dial to match your system’s nameplate line-to-line voltage. The internal logic will automatically scale the trip points based on this setting.
What socket is required for a UL-Listed installation?
For a compliant installation, use an 8-pin OT08-PC or RB08-PC octal socket, which supports 35mm DIN rail or surface mounting.
Will this monitor protect against a phase reversal?
Yes, the unit detects incorrect phase sequence upon power-up and will prevent the motor starter from energizing, protecting equipment from backward rotation.
Disclaimer: While we strive for 100% accuracy, product data and specifications are subject to change. Please contact our team to confirm compatibility or technical details before purchasing.
Product Information
Product Information
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Shipping & Returns
Description
The Littelfuse 201A-9 Monitor is a professional-grade 3-phase plug-in voltage monitor engineered to safeguard motors from fluctuating power conditions. This auto-ranging unit operates across 190-480VAC at 50/60Hz, utilizing a high-speed microcontroller-based voltage sensing circuit to detect imbalances before they lead to winding failure. Unlike standard models, the 201A-9 includes specialized high voltage detection, tripping the 10A output relay if line voltage exceeds 110% of the setpoint. The compact 8-pin octal base design ensures a seamless motor protection relay installation into existing control panels using a standard 35mm DIN rail socket. Integrated LED diagnostics provide immediate visual feedback, distinguishing between phase reversal, low voltage, and unbalance faults. This unit is essential for protecting 3-phase compressors, pumps, and fan motors from single-phasing and harmful transients, reducing unbudgeted downtime for mechanical contractors and facility managers.
Key Benefits- Universal Compatibility: Auto-sensing dual-range logic (200V and 400V) fits a wide variety of HVACR applications without manual jumper settings.
- Advanced Protection: Specific high voltage trip capability prevents insulation breakdown during surge events or utility overvoltage.
- Contractor-Friendly Diagnostics: High-visibility LED flashes specific color patterns to identify the exact cause of a trip, shortening troubleshooting time.
- Robust Build: Solid-state design with phase loss protection ensures reliability in demanding industrial environments.
How do I set the line voltage on the 201A-9?
Rotate the nominal voltage adjustment dial to match your system’s nameplate line-to-line voltage. The internal logic will automatically scale the trip points based on this setting.
What socket is required for a UL-Listed installation?
For a compliant installation, use an 8-pin OT08-PC or RB08-PC octal socket, which supports 35mm DIN rail or surface mounting.
Will this monitor protect against a phase reversal?
Yes, the unit detects incorrect phase sequence upon power-up and will prevent the motor starter from energizing, protecting equipment from backward rotation.
Disclaimer: While we strive for 100% accuracy, product data and specifications are subject to change. Please contact our team to confirm compatibility or technical details before purchasing.
