Description
⚙️ Product Introduction
The SELCO T3300-04 is a three-phase voltage monitoring relay designed for generators, busbars, switchboards, and other AC distribution systems. The T3300 continuously monitors three-phase voltage and provides separate time-delayed overvoltage and undervoltage protection functions. It uses two individual output relays, one for each protection function.
The T3300 uses separate internal transformers for the three voltage measurements and for the relay’s internal electronics supply. This arrangement provides galvanic isolation between the measurement circuits and helps maintain measurement accuracy.
🔧 The relay supports adjustable voltage thresholds, time delays, and hysteresis. It can be connected directly to line-to-line or line-to-neutral voltage within its specified measurement range, reducing the need for separate voltage transformers in suitable installations.
📋 Technical Specifications
| Parameter | Value |
|---|---|
| Brand | SELCO |
| Model | T3300-04 |
| Series | T3300 T-Line |
| Product Name | 3-Phase Voltage Relay |
| Monitoring Function | Overvoltage / Undervoltage |
| Measurement | 3-Phase AC Voltage |
| Voltage Range | 70–120% of nominal |
| Maximum Voltage | 660 VAC |
| Dimensions | 70 × 150 × 115 mm |
| Power Consumption | 5 VA at Un |
⚡ Key Features
• Three-phase voltage measurement
• Separate overvoltage and undervoltage protection
• Time-delayed relay operation
• Adjustable overvoltage level: 100–120%
• Adjustable undervoltage level: 80–100%
• Adjustable delay: 1–10 seconds
• Adjustable hysteresis: 1–10%
• Frequency range: 40–400 Hz
• Maximum voltage: 660 VAC
• Two individual output relays
• Galvanically isolated measurement inputs
• 35 mm DIN-rail or screw mounting
• Polycarbonate flame-retardant enclosure
• Suitable for generator and marine switchboard protection
🛠️ Application & Integration
The SELCO T3300 can be installed in generator control panels, marine switchboards, distribution panels, and industrial power systems where continuous three-phase voltage supervision is required.
The relay monitors each phase and activates the corresponding output when the measured voltage remains outside the configured limit for the selected delay period. The overvoltage relay is normally de-energized, while the undervoltage relay is normally energized.
For replacement work, verify the exact voltage variant before installation. SELCO specifies several T3300 versions, including 230 V, 400/450 V, 100/110 V, and 415/480 V configurations. The T3300-04 marking should therefore be matched against the voltage rating and terminal arrangement of the existing relay.
🛠️ Installation & Maintenance
Before installation, isolate the switchboard or control circuit and verify that the measured voltage is within the permitted range. Check phase connections, relay contacts, nominal voltage, and configured delay settings.
The relay can be mounted on a 35 mm DIN rail or secured using screws. Its specified operating temperature range is -20°C to +70°C. Overall accuracy is approximately ±3% of the highest value, with repeatability of ±1%.
❓ FAQ
Q: What does the SELCO T3300 monitor?
A: It monitors three-phase AC voltage on generators, busbars, and distribution systems.
Q: Does it provide both overvoltage and undervoltage protection?
A: Yes. The T3300 has separate time-delayed overvoltage and undervoltage functions.
Q: What are the adjustable voltage limits?
A: The overvoltage setting is adjustable from 100–120%, while the undervoltage setting is adjustable from 80–100% of nominal voltage.
Q: What is the maximum voltage rating?
A: The published specification lists a maximum voltage of 660 VAC.
Q: How is the T3300 installed?
A: It can be mounted on a 35 mm DIN rail or fixed using screws.
Q: Is the T3300 suitable for marine applications?
A: Yes. The T3300 is designed for generator and busbar voltage monitoring and is used in marine generator and switchboard protection applications.
⭐ Related SELCO Models
- SELCO T3100 Single-Phase Voltage Relay
- SELCO T3200 Insulation Monitoring Relay
- SELCO T3300 Three-Phase Voltage Relay
- SELCO T3500 Frequency Deviation Relay
- SELCO T3000 Frequency Relay
- SELCO T2800 Overcurrent / Earth Fault Relay
- SELCO T2900 Differential Current Relay
- SELCO T4000 Automatic Synchronizer
- SELCO T4400 Load Sharer
- SELCO T8400 Blackout Limiter
