Franklin Electric INCON LTC Load Tap Changer

Franklin Electric INCON LTC Load Tap Changer

The Franklin Electric INCON LTC Load Tap Changers relay critical position information between the LTC and the LTC controller, enabling distribution transformers to run as efficiently as possible. Three different model options are available to order, allowing the user to select the right system solution for specific applications.

The models available are the 1250B, 1250-LTC, and 1511-LTC, which can be ordered by contacting our team, simply by selecting the ‘Request Callback/Quote’ option at the top of the page and specifying the model you require.

The 1250B Model

The 1250B Model receives a signal from a synchro transmitter (1292 series), and is able to provide absolute position feedback. It displays tap position and transmits this information over analogue and serial lines, and works alongside an LTC or voltage regulator. The 1250B also includes a software draghand feature to report highest and lower tap position, and is programmable through the serial port of front panel. An analogue output is provided to SCADA or tap controller.

The 1250-LTC Model

The 1250-LTC Model includes all of the 1250B highlights, plus several other properties. On-tap position is also viewable, with deviation from the tap centre-line. The number of tap changes “up or down to” each tap and total alarms are viewable, as well as the number of consecutive tap changes in one direction. It also displays “unstable signal” and loss of signal alarm, and has tap change relay acknowledgement. It features and optional RS-232 or RS-485 port, as well as option High/Low limit relays function as drag hand contacts. The 1250-LTC also displays the number of days since passing through neutral alarm, and has outputs interface to PLC’s, SCADA RTUs, and substation complexes.

The 1511-LTC Model

The 1511-LTC receives signal from a resistive drumswitch or ‘Slidewire’ transmitter, and has 600 ohms minimum total resistance. It provides a more reliable reading of the transmitter through software filtering and high 24V signal strength.

Model Comparison

Key Features

• Relay critical position information between the LTC and the LTC controller, which enables distribution transformers to run as efficiently as possible
• Absolute position feedback via a synchro transmitter mechanically coupled to the LTC shaft (0-90 VAC)
• High precision measurement with a resolution of 0.1° (6-arc minutes), accuracy ±0.02% full-scale, drift ±0.01%/°C
• Tap-change displacement tracking with programmable alarms for deviation from expected position
• Comprehensive tap counter: total operations, per-tap up/down counts, and multi-change-direction detection, all with alarms
• Neutral pass detection: adjustable alarm for days since last tap passed through neutral to prevent contraflow & contact wear
• Tap-change acknowledgement: relay closes upon successful shift—useful for validating operations
• Runaway LTC protection: trips if too many consecutive taps in one direction, preventing uncontrolled motor operation
• Maintenance planning data: records wear patterns by logging days at highest/lowest taps and count per tap
• Local display & remote outputs: 5‑digit LED (visible up to 23 ft), plus analog (±1 mA, 0–1, 0–2, or 4–20 mA) and digital (RS‑232/RS‑485 Modbus or ASCII)
• Programmable alarms & communications: two Form‑A relays, custom high/low limits, front-panel or serial configuration
• Solid‑state, retrofit-friendly design: small 1/8 DIN unit (< 6.2″ deep), fits existing 1250B enclosures; no periodic calibration required
• Enhanced signal reliability: immunity to AC noise; detects unstable or lost synchro input
• Supports predictive maintenance and cost reduction: helps balance loads, regulate voltage, and reduce energy waste