The DEIF 2FQ and 2FTQ Double Frequency Meters represent highly specialized electromechanical measurement instruments engineered by DEIF Group (Denmark), designed to facilitate safe, visual, and highly precise alternating current (AC) grid frequency monitoring. Within industrial power distribution grids, particularly critical captive networks deployed on maritime vessels, offshore oil rigs, or remote standby generation plants, tying an offline generator aggregate onto an energized active busbar requires three fundamental synchronization benchmarks: phase matching, equal voltage amplitude, and identical frequency baselines. Any considerable frequency mismatch between the incoming supply and the running busbar can induce devastating mechanical torque shocks onto the prime mover shafts and generic high reverse-current transients capable of triggering broad local circuit breaker trips. The DEIF Double Frequency Meter architecture houses two completely isolated measurement mechanisms inside a single standardized DIN enclosure, allowing system operators to evaluate real-time frequency variations and instantly modulate prime mover RPM towards a flawless synchronized match before firing the main air circuit breakers (ACB).

This product lineup features two distinct physical display methodologies engineered to accommodate diverse operational environments:
- **DEIF 2FQ Series (Pointer Type):** Utilizes a dual-pointer layout, displaying either concentric needles or separate pointer mechanics traversing two discrete 90-degree internal scale quadrants. The internal electronics rely on integrated signal transducers that convert raw input frequencies into linear DC currents, driving the pointer needles with high sensitivity and near-zero systemic lag.
- **DEIF 2FTQ Series (Vibrating Reed Type):** Leverages a purely mechanical resonance principle, combining two parallel vertical rows of steel vibrating tongues (reeds) calibrated with extreme precision. As AC current energizes the inner electromagnets, the specific reed matching the supply frequency oscillates visibly. This vibrating reed framework is highly favored within heavy marine switchboard architectures due to its high structural durability, absolute immunity against high-voltage transients, and an informative visual overview of the grid's local frequency spectrum.

Both the 2FQ and 2FTQ instrument families are wrapped in vibration-dampened housings engineered to withstand multi-axis mechanical stress and broad vibration spectrums, securing full type approvals from leading maritime classification authorities like DNV-GL, Lloyd's Register (LR), American Bureau of Shipping (ABS), and Bureau Veritas (BV). The front fascia features premium anti-glare tempered glass paired with a flame-retardant industrial polymer casing, assuring steady continuous deployment spanning decades inside high-ambient, saline-heavy marine engine rooms. These meters remain an essential asset for shipyards, switchgear manufacturers, and heavy power system integrators.

• Manufacturer: DEIF
• Country of Origin: Denmark
• Product Category: Switchboard Double Frequency Meter
• Architectural Variants:
  - DEIF 2FQ: Dual analog pointer indication mechanism
  - DEIF 2FTQ: Mechanical vibrating reed/tongue resonance mechanism
• Accuracy Classification:
  - 2FQ Series (Pointer): Class 0.5 according to international standard IEC/EN 60051
  - 2FTQ Series (Reed): Class 0.5 (Standard reed resolution intervals at 0.5 Hz or 1 Hz)
• Standard Frequency Ranges: 45...55 Hz, 55...65 Hz, or broad range 45...65 Hz
• Rated Voltage Input Configurations: 100V, 115V, 230V, 400V, 440V, 450V AC (Direct connection or via Potential Transformers - PT)
• Voltage Overload Tolerance: 1.2 times nominal voltage continuously; 2 times nominal voltage short-term for 5 seconds
• Internal Power Consumption (Burden): Ultra-efficient, < 3VA per individual measuring system
• Ingress Protection Rating: IP52 front panel protection (Upgradeable to IP54 with dedicated rubber gaskets), IP20 rear screw clamp terminal array
• Housing Composition: High-impact Thermoplastic, self-extinguishing complying with UL 94 V-0 parameters
• Wiring Termination: Rugged heavy-duty screw clamps engineered to handle structural industrial vibrations
• Rated Operational Thermal Band: -25°C to +60°C (Fully certified for worldwide tropical marine climates)
• Enclosure Dimensions: Standardized 96 x 96 mm or 144 x 144 mm bezel layout (Complying with DIN specifications)
• Quality & Marine Class Approvals: CE marked, RoHS compliant, DNV-GL, ABS, Lloyd's Register (LR), Bureau Veritas (BV), RINA