GE PLT+MF UNI 8A 3C0 685995 Multi-Function Time Relay

General Electric PLT+MF UNI 8A 3C0 (MPN: 685995) Multi-Function Time Relay

The General Electric PLT+MF UNI 8A 3C0 (Catalog Ref: 685995) is a high-density, multi-function, multi-voltage DIN-rail time relay for marine switchboards, industrial automation panels and motor control centers (MCC). The GE Pulsar T+ series offers a small 18 mm (1 DIN module) unit that replaces traditional multi-component timing setups with 10 configurable timing functions and a wide universal coil operating range in a single modular footprint.

The PLT+MF UNI 8A 3C0 is equipped with three changeover contacts (3 CO / SPDT) with an 8A AC1 (250V AC) rating. It enables the simultaneous switching of numerous separate control circuits, auxiliary interlocks or telemetry reporting loops. Its wide-range power supply supports AC/DC voltages from 12V to 240V (50/60 Hz), making it immune to line voltage variations often encountered on naval generator busses and remote field distribution boards.

Model Details

• Manufacturer: General Electric (GE Power Controls / Pulsar T+ Range)
• Model Name: PLT+MF UNI 8A 3C0
• Manufacturer Part Number (MPN): 685995
• Product Series: Pulsar T+ Series Modular DIN-Rail Control Devices
• Form Factor: Standard 18 mm Width (1 DIN Module)

Technical Specifications: GE PLT+MF UNI 8A 3C0 685995

Key Features

1. High-Density 3 CO Switching: Houses 3 independent changeover contacts (8A AC1 rating) within a single 18 mm modular housing, reducing required DIN-rail space by up to 66%.
2. Universal Operating Voltage: Accepts 12V–240V AC/DC (50/60 Hz) on coil input, eliminating the need to stock multiple AC and DC coil part variants.
3. 10 Selectable Timing Modes: Covers delay-on-energization, delay-off, symmetrical cycler, pulse-shaping, and latching relay functions in one reference.
4. Vibration-Resistant Terminals: Features IP20 loss-proof Pozidriv screw terminals engineered to withstand industrial vibration and maritime movement without conductor backing-out.
5. Precision Time Setting: Front rotary potentiometers provide coarse multiplier and fine scale adjustments across a continuous range from 0.1s up to 240 hours (10 days).

Primary Applications

• Marine Auxiliary Automation: Main Switchboard (MSB) auto-transfer delays, diesel generator pre-lubrication timing, and bilge high-level alarm delay interlocks.
• HVAC & Ventilation Systems: Cyclic fan reversals, sequence control for compressor delay timers, and dampered ventilation shut-off loops.
• Pumping Systems: Circulating pump alternation, delayed start-up sequence to prevent hydraulic water hammer, and dry-run pump cutoff timing.
• Motor Starter Circuits: Star-Delta transition timing, soft starter bypass confirmation delays, and reverse-run protection interlocks.
• Industrial Process Control: Conveyor anti-jam sequence timing, solenoid valve purging cycles, and emergency lighting delay circuits.

Compatibility

• GE / ABB Modular Enclosures: Linea, Modula, and QuiX DIN-rail consumer units/distribution boards.
• Standard Industrial Panels: Any 35 mm DIN Rail panel (EN 50022 / EN 60715 compliant) from Rittal, Schneider Electric, Siemens, or Eaton.
• PLC/Automation I/O Interfacing: Interoperable with 24V DC transistor output cards from GE Fanuc RX3i/90-30, Siemens S7-1200/1500, Rockwell CompactLogix, and Schneider Modicon.

Frequently Asked Questions

What makes the GE PLT+MF UNI 8A 3C0 (685995) suitable for marine switchboards?

Marine electrical grids often experience voltage variations between harbor power, generator switching, and emergency battery back-up. The GE 685995 features a universal power coil operating from 12V to 240V AC/DC, alongside loss-proof IP20 terminals that prevent wire disconnection due to hull vibration.

How do I wire 3 separate circuits using the GE 685995 relay?

The GE PLT+MF UNI 8A 3C0 features 3 independent changeover contacts (3 CO / 3 PDT). You wire the common line to terminal 15, 25, or 35. Terminals 16, 26, 36 serve as normally closed (NC), while terminals 18, 28, 38 serve as normally open (NO). Each set is electrically isolated up to 250V AC.

Can I replace a 24V DC timer with this GE 12-240V AC/DC unit?

Yes. The GE PLT+MF UNI 8A 3C0 automatically senses and accepts any control voltage within the 12V to 240V AC/DC range, making it a direct retrofit drop-in replacement for fixed 24V DC, 110V AC, or 230V AC single-voltage time relays.

What is the difference between Function A (Delay ON) and Function B (Delay OFF)?

In Delay ON mode (Delay after energization), the timing countdown begins as soon as coil power is applied; contacts switch after the delay elapses. In Delay OFF mode, the output contacts energize immediately upon control signal activation and remain energized for the set time after the control signal is removed.