3-PH PLUG-IN VM/190-480V/ADJ.

Littelfuse 201A-AU-OT 3-Phase Plug-In Voltage Monitor – Auto-Ranging Motor Protection

Protect your three-phase motors with the Littelfuse 201A-AU-OT, a reliable OEM voltage monitor designed for industrial and commercial HVAC and motor control applications. This auto-ranging, dual-range monitor safeguards motors operating between 190–480 VAC, 50/60 Hz, regardless of their size, by detecting harmful power line conditions such as phase loss, under-voltage, over-voltage, and voltage unbalance.

Key Features

• Auto-Ranging Voltage Monitoring: Automatically selects between 200 V and 400 V for fast setup and precise protection

• Adjustable Settings: Trip delay (1–30 s), restart delay (manual or 1–500 s), and voltage unbalance trip point (2–8%)

• Advanced LED Diagnostics: Single LED with five light patterns distinguishes between normal operation and fault conditions

• Microcontroller-Based Monitoring: Continuously senses three-phase voltages to prevent motor damage

• Compact & Flexible Installation: DIN-rail or surface mount (plug into OT08-PC socket)

Specifications

• Input Voltage: 190–480 VAC

• Output Form: Form C relay

• Output Load Rating: Pilot Duty 480 VA @ 240 VAC; General Purpose 10 A @ 240 VAC

• Trip/Restart Accuracy: ±1%

• Operating Temperature: -40°C to 70°C (-40°F to 158°F)

• Storage Temperature: -40°C to 80°C (-40°F to 176°F)

• Humidity: 10–95% non-condensing

Benefits

• Constantly monitors 3-phase voltages to prevent motor damage

• Protects against phase reversal, over-voltage, under-voltage, voltage unbalance, and single-phase faults

• Quick visual fault identification reduces downtime

• Supports a variety of motors, reducing nuisance tripping

• Compact design saves space in control panels

The Littelfuse 201A-AU-OT is the ideal solution for professionals seeking reliable, high-performance motor protection with adjustable settings and advanced diagnostics. Ensure safe and efficient operation of your motors with this intelligent voltage monitor.