GE IC3600LDDB1 Dual Flame Detector Amplifier Card

Description

In gas turbine and compressor drive applications that still rely on Speedtronic Mark I or Mark II control systems, one of the most common causes of unplanned trips is loss of flame detection or erratic flame-scanner readings. Electrical noise from igniters, ground loops, poor cable shielding, and aging UV tubes can turn a stable flame signal into intermittent garbage that forces the control system to drop fuel and shut the unit down. Even worse, a failed flame card that no longer recognizes legitimate flame can prevent start-up entirely, costing hours or days of lost generation while technicians chase ghosts across multiple scanner heads.

The GE IC3600LDDB1 – the dual flame detector amplifier card for Mark I/II – was specifically engineered to eliminate these problems. It accepts inputs from two independent GE 4N-series or third-party UV flame scanners, provides fully isolated high-gain amplification, applies intelligent flicker discrimination, and delivers clean, reliable “flame on/off” logic signals plus a 0–10 V analog intensity output to the Speedtronic logic rack. When plants need rock-solid flame detection in harsh electrical environments without migrating to Mark VIe, the IC3600LDDB1 is the proven drop-in solution that has kept thousands of Frame 5, 6, and 7 machines running for decades.

The IC3600LDDB1 occupies a single slot in the main Speedtronic card rack and interfaces directly with the existing flame scanner wiring through front barrier terminals. Each of the two channels has its own gain and threshold potentiometers, allowing independent tuning for main and pilot flames or for scanners viewing different burner zones. The card’s flicker-frequency discrimination circuit (tunable 20–120 Hz) rejects arc noise from spark igniters while still responding instantly to legitimate flame flicker, dramatically reducing nuisance trips during light-off sequences.

Output is simple and bulletproof: two sets of isolated Form-C relay contacts (flame proven) wire directly into the master protective logic, while the analog intensity signals feed the operator’s flame-strength meters and historian. On-card test jacks and a built-in UV test source let a technician verify gain, threshold, and relay operation in minutes without removing scanner heads or running the turbine. In dual-redundant Mark II installations, two IC3600LDDB1 cards are typically voted 1oo2D or 2oo2 to achieve the required diagnostic coverage for SIL-rated flame detection.

Choosing the GE IC3600LDDB1 means you regain the flame detection reliability the turbine had when it was new, but with far fewer false trips and far faster troubleshooting. Plants routinely report that swapping older IC3600LDFA or single-channel cards for the IC3600LDDB1 cuts flame-related outages by 70–90 %, often eliminating an entire category of forced outages from the monthly report. The isolated outputs and adjustable discrimination also allow you to keep the original UV scanners in service years longer, deferring expensive head replacements until the next major.

Maintenance teams love the on-card test source and the fact that calibration is just two potentiometers per channel instead of chasing problems in the field. In practice, the IC3600LDDB1 often becomes the last flame card you ever need to buy for that machine.

The IC3600LDDB1 remains the standard in operating Frame 5 and Frame 7 simple-cycle units, combined-cycle power blocks, and pipeline compressor stations where Mark I/II controls are still the backbone. It is heavily used during life-extension projects when owners want to meet modern insurance requirements for flame detection without the cost of a full control upgrade. Offshore platforms and refineries with high EMI environments rely on its robust isolation to maintain critical system uptime during ignition sequences in explosive atmospheres.

IC3600LDDA1 – Earlier single-channel version (replace with LDDB1 for redundancy)

IC3600LDFB1 – Higher-gain version for weak-signal quartz scanners

IC3600QOXB – Flame scanner test panel interface module

UV170 – Current GE replacement flame scanner head compatible with LDDB1

44A294521-G01 – Wiring harness kit for retrofitting older LDFA racks

DS3820FDCA – Mark IV-era flame card (migration path for full system upgrade)

IC3600VFD1 – Optional flicker discriminator add-on for very noisy environments

Before installing an IC3600LDDB1, verify that scanner supply voltage at the card terminals is 320–350 VDC (Mark I/II standard) and that coaxial cables are properly terminated with the shield grounded only at the rack end. Transfer gain and threshold pot settings from the old card or start with mid-range and fine-tune during the next start sequence. If you’re replacing a single-channel card, decide whether to wire both channels for main + pilot or to parallel them for extra noise rejection.

In service, annual validation is straightforward: activate the on-card UV test lamp, confirm both relays pick up within 1 second, and verify analog output reaches 8–9 V. Check scanner head windows for soot buildup at the same time. Relay contacts are gold-flashed and almost never fail, but a quick continuity check across the NO contacts during outages keeps auditors happy.