TR-115/36

Aircraft step-down transformer TR-115/36

TR-115/36 is an aircraft step-down transformer used in instrument power supply circuits. It converts single-phase AC voltage from the aircraft bus to a lower AC voltage required by remote inductive pressure gauges and similar measuring equipment. The transformer is not a sensor and does not measure pressure itself. Its role is to supply the correct electrical power to instruments that need 36 V AC for stable indication in the cockpit.

Power supply function of TR-115/36

In operation, TR-115/36 receives 115 V AC from the onboard electrical system and outputs 36 V AC for the connected measuring circuit. This reduced voltage is used by inductive remote pressure indication systems, where the cockpit indicator and transmitter circuit must be powered from a defined AC source. If pressure indication becomes unstable or disappears, the fault may be in the transformer, instrument wiring, indicator, transmitter, or supply bus. The transformer should be checked as part of the full instrument circuit.

TR-115/36 in pressure indication systems

TR-115/36 is used in aircraft systems where pressure is measured remotely and shown on cockpit instruments. Such circuits are common in engine, hydraulic, fuel, oil, pneumatic, and other onboard systems, depending on the aircraft layout. On Mi-8MTV and Mi-17 helicopters, this type of transformer is associated with cockpit instrument power supply for remote inductive gauges. Exact installation should be confirmed by the aircraft wiring diagram and instrument list.

Main and standby use of TR-115/36

Aircraft documentation may include TR-115/36 in main and standby transformer configurations. This arrangement allows pressure indication equipment to receive power from a defined instrument supply path, with redundancy where the aircraft system requires it. During replacement, it is important to confirm whether the transformer is installed in the main or standby branch, because wiring, protection and connected instruments may differ. A physically similar transformer should not be installed without checking the circuit designation.

Identification and ordering of TR-115/36

Before ordering TR-115/36, the marking should be compared with the aircraft parts catalog, cockpit instrument wiring diagram or transformer operating manual. The input voltage, output voltage, frequency and installation branch must match the aircraft documentation. For correct selection, provide the aircraft type, instrument system, installed transformer marking and a photo of the data plate if available. The product is also known under alternative designations TR115/36, TR-115/36 and Тр-115/36.

Product Type: Aircraft step-down transformer
Function: Power supply of remote inductive pressure gauges
Application / Where Used: Aircraft instrument power supply systems
System / Installation Area: Cockpit electrical panels / instrument power circuits
Compatible Aircraft / Equipment: Mi-8MTV, Mi-17 helicopters and related avionics
Input Voltage: 115 V AC
Output Voltage: 36 V AC
Frequency Range: 400 Hz
Working Medium: Electrical energy, AC
Part of System / Included in Set: Main and standby transformer configuration
Technical Documentation: Transformer TR-115/36 Technical Description and Operating Manual

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