STG-12TM Series 3
Starter-Generator
Description
STG-12TM Series 3 product function
STG-12TM Series 3 is classified as an Aircraft starter-generator. Its primary role is engine starting followed by electrical power generation. The complete designation, series and suffix letters form part of the identity and must not be shortened in an enquiry. This catalogue page supports product identification but does not replace the passport, illustrated parts catalogue or approved maintenance data for a particular aircraft installation.
The previously collected card data records the following: The STG-12TM (Series 3) is a DC starter-generator designed for use in aviation power systems.It serves a dual purpose — functioning both as a starter for engine start and as a generator supplying electrical power to the onboard network once the engine is running. The unit is typically installed on the accessory gearbox (upper gearbox) of helicopter or aircraft engines, where it is driven mechanically through a gear train.The generator delivers a nominal output of 28.5 V DC and provides reliable power for avionics, control systems, and onboard equipment.It is widely used on Mi-8, Mi-17, and related helicopter series, as well as other aircraft requiring a robust combined starter-generator system. Type: DC starter-generator, dual operational mode (starter and generator)Series: 3rd series, latest modification of the STG-12TM lineNominal output voltage: 28.5 volts DCNominal load current: up to 400 amperesRated power output: 12 kilowattsRotational speed range: from 4,200 to 9,000 revolutions per minuteDimensions: 229.5 millimeters in diameter and 504 millimeters in lengthWeight: approximately 35.5 kilogramsMounting position: installed on the engine accessory (upper) gearboxDrive system: mechanical drive through the engine gear trainCooling method: air-cooled, self-ventilated through housing ventsExcitation type: shunt-excited DC machine for stable output voltageOperating modes: starter mode and generator mode, automatically switched depending on engine stateStandard operating voltage system: 28-volt DC onboard electrical networkTypical application: Mi-8 and Mi-17 helicopter power systems, as well as other aircraft using similar 28-V DC systems These facts are retained for identification, but numerical values must be checked against the passport of the individual unit before use.
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Role in the electrical system
An electrical machine or test source operates as part of a matched system. For a power unit, that system includes the mechanical drive, regulator, protection equipment, switching, wiring and connected loads. For a measuring generator, it includes the output circuit, load, monitoring equipment and approved test method. The general conversion principle is described in the electric generator reference. The exact STG-12TM Series 3 connection must follow the documentation for the installed equipment.
A shared voltage or power rating does not establish interchangeability. Direction of rotation, speed range, drive flange, shaft, cooling, connectors, regulation, brush arrangement and permitted duty can differ. A starter-generator also requires verification in both operating modes, while an AC generator requires confirmation of frequency, phase configuration and the associated regulation and protection units.
Parameters and execution verification
Selection checks include the nameplate designation, series, technical specification, voltage, current or power, rotational speed, cooling method, direction of rotation and mass. This page retains only information already recorded in the Technical Details or confirmed for the exact designation. A missing parameter must be obtained from the offered unit passport rather than copied from a neighbouring family model.
A letter suffix or series number may identify a different construction, cooling arrangement, drive, rotation direction or electrical circuit. Hyphenated, compact and transliterated forms can be useful search variants, but they are not presented as separate interchangeable executions.
Installation and associated equipment
Before installation, inspect the mounting geometry, shaft and splines, fasteners, free rotation, collector or slip-ring condition, brushes, connectors, insulation and cooling passages as applicable. Regulators and protection units must be selected from the wiring data for the exact installation. Aircraft application is stated only when supported by documentation; visual similarity and a related designation are not sufficient evidence.
Related catalogue positions include STG-12TMO-1000, STG-18TM-1000, STG-12TM, STG-18TMO-1000. These links provide navigation within the family and do not imply interchangeability. More electrical power units are listed in the Generators & Starter-Generators category.
Incoming inspection and maintenance
Incoming inspection should compare the marking and serial number with the supporting records and examine the housing, mounting points, terminals, connectors and seals. For a stored unit, confirm the last inspection date and the approved depreservation requirements. Electrical measurements, insulation testing, bench rotation and output checks must follow an approved procedure. Brush machines also require brush and collector assessment; brushless machines require attention to the exciter, rotating rectifier and bearings.
External appearance does not confirm serviceability. The required condition, inspection level, delivery set, passport and maintenance records should be agreed before installation. Release to service remains the responsibility of an authorized organization.
Identification and ordering of STG-12TM Series 3
An enquiry should state the exact STG-12TM Series 3 designation, series and execution, installed-system type, required condition and quantity. A clear nameplate photograph and the relevant parts-catalogue reference are useful. For replacement, also provide the drive, regulator and protection-unit designations and the network parameters. These details allow the configuration to be checked without assumptions and prevent confusion with a similarly named modification.
Price, actual availability, lead time, delivery scope and documentation are confirmed separately for the offered unit. State whether a passport, logbook, test report, preservation record, mating connector or mounting hardware is required.
Technical details
- Product Type
- Aircraft starter-generator
- Primary Designation
- STG-12TM Series 3
- Alternative Designations
- STG-12TM Series 3; STG 12TM Series 3; STG12TMSeries3
- Function
- Engine starting followed by electrical power generation
- System
- Aircraft power-supply or starting system; exact composition per documentation
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- Application
- Only as confirmed by the product passport, illustrated parts catalogue and aircraft documentation
- Installation Check
- Verify drive, mounting, shaft, rotation direction, cooling, connectors and associated equipment
- Selection Basis
- Exact designation, series, nameplate and documentation for the individual installation
- Interchangeability
- Not established by a related designation or matching individual electrical ratings alone
- Enquiry Data
- Designation, series, required condition, quantity, nameplate photo and required document set
- Documentation
- Product passport, illustrated parts catalogue and approved operating or repair documentation
- Category
- Generators & Starter-Generators
- Retained Technical Data
- Type: DC starter-generator, dual operational mode (starter and generator)Series: 3rd series, latest modification of the STG-12TM lineNominal output voltage: 28.5 volts DCNominal load current: up to 400 amperesRated power output: 12 kilowattsRotational speed range: from 4,200 to 9,000 revolutions per minuteDimensions: 229.5 millimeters in diameter and 504 millimeters in lengthWeight: approximately 35.5 kilogramsMounting position: installed on the engine accessory (upper) gearboxDrive system: mechanical drive through the engine gear trainCooling method: air-cooled, self-ventilated through housing ventsExcitation type: shunt-excited DC machine for stable output voltageOperating modes: starter mode and generator mode, automatically switched depending on engine stateStandard operating voltage system: 28-volt DC onboard electrical networkTypical application: Mi-8 and Mi-17 helicopter power systems, as well as other aircraft using similar 28-V DC systems
Payment & delivery
Orders ship from our hub in Dubai. Partner stock is first transferred to Dubai, then shipped to you.
Dubai stock: 100% before dispatch. Partner stock (Remote stock) and Pre-order: 50% advance payment to start the order and 50% before shipment from Dubai to you.
Availability, lead time, delivery cost and payment terms are confirmed for your order before payment.
Payment & delivery terms