Technical Documentation

Digital Three-Phase Protection Relay

Model: STVP-936-63A

Brand: SINOTIMER

Current Capacity: adjustable 163 A

Power Supply Voltage: 3 x 230 V / 400 V AC

Frequency: 50 / 60 Hz

Installation: DIN rail

Display: digital (voltage and current)

Recovery Operation: automatic

General Description

The three-phase relay is an electronic device designed for monitoring and protecting three-phase electrical networks. It continuously monitors the voltage and current on each phase and automatically disconnects the power supply if abnormal parameters occur that could damage connected equipment. Once parameters return to normal limits, the device automatically reconnects the circuit without intervention.

Protection Functions

• Overvoltage protection
• Undervoltage protection
• Overcurrent protection
• Phase loss protection
• Phase imbalance protection
• Phase sequence reversal protection
• Neutral conductor loss protection
• Display of voltage and current on each phase
• Automatic restoration after fault

Operating Principle

The relay continuously measures the voltage and current of each phase. If one or more values exceed set limits (overvoltage, undervoltage, overcurrent, or imbalance), the relay disconnects power to the load. After parameters return to normal levels and the preset delay time expires, the device automatically restores the power supply.

Available Settings

• Adjustable low voltage
• Adjustable high voltage
• Adjustable maximum current (163 A)
• Disconnection delay time
• Auto-reconnection time
• Enable/Disable phase sequence protection

Electrical Connections

• Three-phase connection: L1, L2, L3 + N
• Relay control coil for disconnection
• Mounting on electrical panel on standard 35 mm DIN rail
• Use of power contact for high loads and additional protection (circuit breakers or fuses) is recommended.

Technical Parameters

• Nominal Voltage: 3 x 230 V / 400 V AC
• Operating Current: 163 A (adjustable)
• Response Time: fast, under 1 second
• Operating Temperature: approximately -20°C to +60°C
• Low power consumption
• Fire-resistant construction for installation in electrical panels

Application Areas

• Three-phase electrical panels
• Three-phase electric motors
• Pumps, compressors, industrial fans
• HVAC systems
• Residential and commercial electrical installations
• Protection of sensitive equipment from voltage fluctuations

Important Remarks

• The device does not replace short-circuit protection
• For inductive loads, using an external contact is recommended
• Installation must be performed by authorized personnel