3-PHASE VOLTAGE MONITOR/ 190-4

Littelfuse 202 Monitor – 3-Phase Voltage Monitor (190–480 VAC, Series 202)

The Littelfuse 202 3-Phase Voltage Monitor (Series 202) is a microcontroller-based protection relay engineered to safeguard motors and industrial equipment from harmful power line conditions. Designed for use with 190–480 VAC, 50/60 Hz systems, this compact voltage monitor continuously analyzes incoming voltage to detect overvoltage, undervoltage, phase loss, phase reversal, and voltage unbalance.

When an abnormal condition is detected, the internal SPDT output relay deactivates after a preset trip delay, helping prevent nuisance shutdowns caused by brief voltage fluctuations. Once voltage returns to acceptable levels, the relay automatically reactivates after the adjustable restart delay, ensuring safe and reliable system recovery.

This unit is ideal for protecting single-phase and three-phase motors, compressors, HVAC equipment, pumps, and industrial machinery.

Key Features & Benefits

Wide Input Voltage Range: 190–480 VAC
Compatible with 50/60 Hz (50 Hz increases delay timers by 20%)
SPDT Output Relay for flexible control integration
Microcontroller-based precision voltage sensing
Adjustable Restart Delay: Manual; 2–300 seconds
Trip Delay Protection:
- Under/Over Voltage: 4 seconds
- Unbalance/Phase Faults: 2 seconds
Helps prevent nuisance tripping
Compact Design: 2.5" H x 2.5" W x 1.4" D
Operating Temperature: -40°F to 158°F (-40°C to 70°C)
Humidity Rating: 95% non-condensing

Technical Specifications

Input Voltage: 190–480 VAC
Input Tolerance: ±10%
Input Phase Sequence: A, B, C
Overvoltage Trip: 110%
Overvoltage Reset: 107%
Undervoltage Trip: 90%
Undervoltage Reset: 93%
Voltage Unbalance Trip: 6%
Voltage Unbalance Reset: 4.5%
Repeat Accuracy: ±0.5%
Trip Point Accuracy: ±1%
Output Load Rating:
- General Purpose: 10A @ 240 VAC
- Pilot Duty: 480 VA @ 240 VAC
Maximum Input Power: 5W
Dielectric Breakdown: ≥1960
Termination Type: 0.25" Male Quick Connect
Mounting Method: 1/4" Socket Head Cap Screw (Customer Supplied)
Dimensions: 2.5" H x 2.5" W x 1.4" D (63.5 x 63.5 x 35.6 mm)

Applications

HVAC systems
Industrial motor protection
Pumps and compressors
Refrigeration systems
Manufacturing equipment
Power distribution panels

Reliable Motor & Equipment Protection

Voltage disturbances such as imbalance, phase loss, overvoltage, and undervoltage can shorten motor life and cause costly downtime. The Littelfuse 202 3-Phase Voltage Monitor delivers accurate, fast-response protection with adjustable delays to maintain system stability and extend equipment lifespan.

Order today to ensure dependable voltage monitoring and long-term equipment protection.

ELECTRICAL

Littelfuse 201A-AU Monitor

Littelfuse 201A-AU-OT Monitor

Littelfuse 0JTD030.T Fuse

Littelfuse 102A Monitor

Littelfuse 201A Monitor

Littelfuse 0JTD090.V Fuse

Littelfuse 0JTD060.T Fuse

Littelfuse 201A-9 Monitor

Littelfuse 202-RP Relay

Littelfuse 250A Monitor

Littelfuse 202 Monitor

Littelfuse LSRX Sensor