Adjustable Voltage Protection Relay – Single Phase Over/Under Voltage Protector

The Adjustable Voltage Protection Relay is a smart protection device designed to safeguard electrical appliances and equipment from abnormal voltage conditions. It automatically disconnects the power supply when the voltage exceeds or drops below the preset limits, preventing damage caused by overvoltage or undervoltage.

This protector continuously monitors the incoming power supply and restores the connection automatically once the voltage returns to the safe operating range. It is ideal for residential, commercial, and industrial applications where stable voltage is critical.

Key Features

• Over Voltage Protection: Automatically disconnects the load when voltage rises above the set limit.
• Under Voltage Protection: Cuts off power when voltage falls below the safe threshold.
• Adjustable Voltage Limits: User can set upper and lower voltage protection values.
• Adjustable Reconnection Delay: Prevents frequent switching by adding a delay before reconnecting.
• Digital LED Display: Shows real-time voltage values and device status.
• High Accuracy Monitoring: Provides precise voltage measurement.
• Automatic Recovery: Restores power once voltage returns to normal conditions.
• DIN Rail Mount Design: Easy installation in electrical distribution boards.

Technical Specifications

• Rated Voltage: 220V – 240V AC
• Frequency: 50/60 Hz
• Over Voltage Protection Range: Adjustable (typically 230V – 300V)
• Under Voltage Protection Range: Adjustable (typically 140V – 210V)
• Current Rating: Up to 63A
• Reconnection Delay: Adjustable (5 – 300 seconds)
• Display: LED digital display
• Mounting: Standard DIN rail
• Operating Temperature: -25°C to +55°C

Applications

• Home electrical protection
• Air conditioners
• Refrigerators
• Washing machines
• Pumps and motors
• Office equipment
• Sensitive electronic devices

Working Principle

The device constantly measures the incoming voltage from the power supply. If the voltage goes beyond the preset upper or lower limit, the internal relay disconnects the load immediately. After the voltage returns to the normal range and the preset delay time expires, the device reconnects the power automatically.

Installation

The protector is installed between the main circuit breaker (MCB) and the load. It is designed for DIN rail mounting, making it suitable for installation inside electrical distribution panels.