Description
GIC MD21DF Voltage Monitoring Relay
The GIC MD21DF is a compact and reliable voltage monitoring relay designed to protect electrical systems from voltage fluctuations and phase failures. It supports 3-phase voltage input and offers fault detection like over-voltage, under-voltage, phase loss, and phase sequence errors. It is widely used in control panels and industrial equipment for power safety and system stability.
MD21DF – Technical Specifications
- Supply Voltage (±6%): 208 – 480 VAC (3 Phase 3 Wire)
- Supply Variation: -12% to +10% (of rated supply)
- Frequency: 50/60 Hz
- Power Consumption (Max.): 3.5 VA
- Settable Nominal Voltage: 208 – 220 – 380 – 400 – 415 – 440 – 480 VAC
- Phase Loss: Yes
- Phase Sequence: Yes
- Trip Levels:
- Phase Asymmetry: N/A
- Under Voltage: -20% to -20% (of rated supply)
- Over Voltage: +2% to +20% (of rated supply)
- Time Delay:
- On Delay: 5 s
- Trip Time (OFF Delay): 0.5 to 15 s (Selectable)
- Relay Output: 1 C/O
- Contact Rating: 5A @ 250 VAC / 30 VDC (Resistive)
- Electrical Life: 1×10⁵
- Mechanical Life: 3×10⁶
- Utilization Category:
- AC – 15: Rated Voltage (Ue): 120/240 V, Rated Current (Ie): 3.0/1.5 A
- DC – 13: Rated Voltage (Ue): 24/125/250 V, Rated Current (Ie): 0.20/0.22/0.1 A
- LED Indication:
- Healthy: Red LED: Supply Healthy → Continuous ON, Phase Reverse → Flashing
- UV: Red LED: Under Voltage → Continuous ON
- OV: Red LED: Over Voltage → Continuous ON
- Asymmetry: Red LED: Asymmetry → Continuous ON
- All LEDs: Phase Fail or Higher Cut OFF (>560 VAC) or lower cut off (<175 VAC). Blinking → Pot changed during running conditions
- Operating Temperature: -15°C to +60°C
- Storage Temperature: -20°C to +80°C
- Humidity (Non-Condensing): 95% (Rh)
- Enclosure: Flame Retardant UL 94-V0
- Dimension (W x H x D) in mm: 18 x 59 x 90
- Weight (unpacked) Approx.: 70 g
- Mounting: Base / DIN rail
- Degree of Protection: IP 20 for Terminal, IP 30 for Enclosure
Key Features
- Real-time monitoring of voltage and phase conditions
- Detects phase loss and incorrect sequence
- Adjustable over and under-voltage thresholds
- User-settable trip delay timing
- Compact DIN rail mounting
- LED indication for quick fault identification
Benefits of Voltage Monitoring Relay
- Prevents costly electrical damage from voltage faults
- Enhances equipment lifespan and safety
- Easy to install and configure
- Saves time in diagnostics with LED fault display
- Supports continuous and reliable operations in harsh environments
Applications
- Industrial control panels
- Generators and backup systems
- Pump and motor control systems
- Commercial building power distribution
- HVAC and refrigeration equipment
How to Use
To use the GIC MD21DF, mount it on a DIN rail in your electrical panel. Connect the 3-phase supply to its terminals. Set the desired voltage thresholds and trip delay using the onboard dials. Once powered, the relay continuously checks the voltage levels and phase sequence. If the supply goes beyond set limits or a phase error occurs, the relay switches its output to prevent damage to the connected system. LED indicators help identify the exact issue quickly.
Why You Should Buy
The GIC MD21DF voltage monitoring relay is a smart choice for protecting any 3-phase electrical system. It offers easy setup, quick fault detection, and is made by a trusted Indian manufacturer. Ideal for both small control panels and large industrial systems, it ensures reliable protection from electrical issues.
Where and Who Uses It
- Where: Control cabinets, industrial equipment, commercial power panels
- Who: Panel builders, electrical contractors, OEMs, maintenance teams, factory engineers
About the Manufacturer
GIC India is a leading Indian brand in industrial automation and electrical control products. Known for innovation and quality, GIC manufactures timers, relays, counters, and monitoring devices that meet global standards. Their solutions are widely used in industrial, commercial, and infrastructure applications across India and abroad.
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