DChV-2500

Function in the engine monitoring system

The transducer works with a toothed inductor that forms part of the engine installation. As the inductor rotates past the magnetic pole of the sensor, the magnetic circuit changes periodically and an alternating voltage is induced in each winding. The frequency of the resulting pulses is proportional to rotor speed. The inductor is not included in the DChV-2500 transducer delivery set, so the sensor must be matched to the correct engine gear, operating gap and wiring circuit defined by the maintenance manual.

Published training documentation describes an engine instrumentation arrangement using five sensors: two on the low-pressure rotor drive, one on the high-pressure rotor drive and two on the free-turbine drive. The exact quantity and station applicable to an individual aircraft depend on the installed engine modification. Signals may be used for speed indication, automatic control and engine protection. Cross-sells and links on this page identify related aviation sensors only; they do not establish functional substitution.

Construction and electrical characteristics

The sensing assembly contains a permanent magnet and a frameless coil with two heat-resistant windings. The active parts are enclosed in a thin-walled, nonmagnetic stainless-steel housing. A shoulder and flange locate the transducer in the engine drive assembly, while a four-contact receptacle connects it to the aircraft wiring. Technical guidance identifies a mating 2РМД18 connector family with 1.5 mm contact pins. Fuel or oil must not be allowed on the current-carrying connector parts even though the magnetic end of the installed sensor may be exposed to engine-oil vapour or splash.

For a documented 32-tooth inductor and approximately 1.3 mm operating gap, the reference characteristic specifies at least 180 mV at 250 Hz and at least 1 V at 2500 Hz with a 2 kΩ active load on the tested winding. In that arrangement, 2500 Hz corresponds to 100% maximum rotor speed. These values describe the stated test configuration and should not be transferred to a different inductor or wiring arrangement without the applicable passport and engine manual.

Environmental limits and installation checks

The documented continuous medium-temperature range is −60 to +220 °C. Short exposure up to +300 °C is permitted for no more than two minutes in one engine operating cycle, with total exposure limited to 1.5% of the assigned service life. The specified atmospheric-pressure range is 5 to 1750 mmHg, and relative humidity may reach 100% at temperatures up to +40 °C. Minimum insulation resistance is stated as 20 MΩ under normal conditions, 1 MΩ at high humidity and 5 MΩ at maximum operating temperature. Reference mass is not more than 0.09 kg.

Before installation, inspect the housing, flange, connector pins and sealing surfaces. Confirm the operating gap, secure mounting and absence of contamination. After connection, both independent circuits should be checked against approved test limits. The exact aircraft position and test procedure must come from the engine maintenance manual, illustrated parts catalogue and product passport. The TV3-117 engine family is used on several helicopter types, including Mi-8 and Mi-17 variants, but applicability of this exact sensor must still be confirmed for the installed engine execution.

Identification, ordering and related sensors

Order the product by the complete DChV-2500 designation and retain the original Cyrillic form ДЧВ-2500 in supporting documentation. Search variants such as DCHV-2500 and DChV 2500 may refer to the same item. The related DChV-2500A is an interchangeable execution, while its suffix remains useful for identification and document matching. More engine and aircraft measuring components are listed in the Aviamisto Sensors category. An enquiry should state the engine or aircraft type, required condition, connector and whether a passport or test report is required.