Littelfuse 201A, 201A Series, 3-Phase Voltage/Phase Monitor, Voltage Asymmetry, Voltage Sensing AC 190 ~ 480VAC, DIN-rail or surface mountable
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The 201A series is a three-phase, auto-ranging, dual-range voltage monitor that protects 190–480 V ac, 50*/60 Hz motors regardless of their size. This monitor provides a user-selectable nominal voltage setpoint and will automatically select between the 200 V and 400 V range. It includes advanced, single LED diagnostics where color and light patterns distinguish between faults and normal conditions. This unique microcontroller-based voltage and phase-sensing unit constantly monitors the three-phase voltages to detect harmful power line conditions. When a harmful condition is detected, the output relay is deactivated after a specified trip delay. The output relay reactivates after power line conditions return to acceptable levels for a specified restart delay time.
*Note: 50 Hz will increase all delay times by 20%.
Frequency | 50*/60Hz |
Functional Characteristics | |
Low Voltage (% of setpoint) |
Trip 90%±1% Reset 93%±1% |
Voltage Unbalance (NEMA) |
Trip 6% Reset 4.5% |
Optional High Voltage (% of setpoint) |
Trip 110% ±1% Reset 107% ±1% |
Trip Delay Time |
Low/High Voltage 4 seconds (standard) Unbalance & Phasing Faults 2 seconds |
Restart Delay Time |
After a Fault 2 seconds (standard) After a Complete Power Loss 2 seconds (standard) |
Output Contact Rating (SPDT) |
Pilot Duty 480 VA @ 240 V ac General Purpose 10 A @ 240 V ac |
General Characteristics | |
Ambient Temperature Range | -20° to 70 °C (-4° to 158 °F) |
Trip & Reset Accuracy | ±1% |
Maximum Input Power | 5 W |
Relative Humidity | 10–95%, non-condensing per IEC 68-2-3 |
Terminal Torque | 12 in.-lbs. (for OT08-PC socket) |
Wire Size | 12–22 AWG solid or stranded |
Transient Protection (Internal) | 2500 V for 10 ms |
Standards Passed |
Electrostatic Discharge (ESD) IEC 61000-4-2, Level 3, 6 kV contact, 8 kV air |
Dimensions |
H 44.5 mm (1.75”) W 60.3 mm (2.38'') D 104.8 mm (4.13”) |
Mounting Method | #6 screws |
Certification & Compliance |
UL UL508 (File #E68520) |