WHAT IS AN AGL ISOLATING TRANSFORMER?
The AGL isolating transformer is one of the most important field components in a conventional series-circuit lighting system. It is the electrical interface between the primary AGL series circuit and an individual light fixture or other field load.
In simple terms
- The CCR controls the series-circuit current
- The isolating transformer transfers power from the primary circuit to the individual fitting and provides electrical isolation
For FAA-based systems, series-to-series isolation transformers are covered by FAA AC 150/5345-47C. It identifies L-830 transformers for 60 Hz and L-831 transformers for 50 Hz.
Main purposes
- Isolate the individual fitting from the primary series circuit.
- Transfer power from the primary winding to the secondary winding.
- Provide the secondary characteristics the fitting needs.
- Allow individual fixtures to be connected into a common series circuit.
- Maintain reliable operation underground, wet and outdoors.
PRIMARY SIDE VS SECONDARY SIDE
Primary side
The primary winding is connected into the airport series circuit. Typical primary currents are 6.6 A or 20 A, and the actual circuit current must match the transformer design.
Secondary side
The secondary winding supplies the individual fitting. Depending on type it is designed for 6.6 A, 20 A or other equipment-specific requirements.
PRIMARY CCR → Series circuit → Transformer SECONDARY Transformer → Individual fitting
Why a single failed light does not open the loop
The primary winding stays in the series circuit even when the secondary-side fitting has a fault, so an individual lamp or fixture failure does not automatically open the primary series circuit. This is one of the main practical advantages of the isolation-transformer arrangement.
The reverse is not true: the primary winding and its leads are part of the series loop, so an open primary winding, lead or connector takes the whole circuit out, not just one fitting. Many open secondaries (for example a run of failed lamps) also lightly load the CCR, which some CCR designs tolerate poorly (see Note 07).
HOW IT WORKS
The transformer works by electromagnetic induction. Alternating current in the primary winding creates changing magnetic flux in the core, which induces voltage in the secondary winding. The windings are electrically separate but magnetically coupled.
Ideal transformer: Vp / Vs = Np / Ns Vp × Ip ≈ Vs × Is
FAA TYPES: L-830 AND L-831
L-830
60 Hz series-to-series isolation transformer.
L-831
50 Hz series-to-series isolation transformer.
The numerical suffix identifies the specified wattage and current characteristics. For example L-830-6 is 60 Hz, 200 W, 6.6 A primary, 6.6 A secondary; the 50 Hz equivalent is L-831-6 with the same characteristics.
Full type table (AC 150/5345-47C)
The same characteristics apply to the L-831 version of each type. Primary voltage rating is 5,000 V and secondary voltage rating is 600 V.
| FAA type | Wattage | Primary current | Secondary current |
|---|---|---|---|
| L-830-1 / L-831-1 | 30/45 W | 6.6 A | 6.6 A |
| L-830-2 / L-831-2 | 30/45 W | 20 A | 6.6 A |
| L-830-3 / L-831-3 | 65 W | 6.6 A | 6.6 A |
| L-830-4 / L-831-4 | 100 W | 6.6 A | 6.6 A |
| L-830-5 / L-831-5 | 100 W | 20 A | 6.6 A |
| L-830-6 / L-831-6 | 200 W | 6.6 A | 6.6 A |
| L-830-7 / L-831-7 | 200 W | 20 A | 6.6 A |
| L-830-8 / L-831-8 | 300 W | 6.6 A | 20 A |
| L-830-9 / L-831-9 | 300 W | 20 A | 20 A |
| L-830-10 / L-831-10 | 300 W | 6.6 A | 6.6 A |
| L-830-11 / L-831-11 | 300 W | 20 A | 6.6 A |
| L-830-12 / L-831-12 | 500 W | 6.6 A | 20 A |
| L-830-13 / L-831-13 | 500 W | 20 A | 20 A |
| L-830-14 / L-831-14 | 500 W | 6.6 A | 6.6 A |
| L-830-15 / L-831-15 | 500 W | 20 A | 6.6 A |
| L-830-16 / L-831-16 | 10/15 W | 6.6 A | 6.6 A |
| L-830-17 / L-831-17 | 20/25 W | 6.6 A | 6.6 A |
| L-830-18 / L-831-18 | 150 W | 6.6 A | 6.6 A |
| L-830-19 / L-831-19 | 150 W | 20 A | 6.6 A |
READING THE COMPLETE RATING
Typical ratings are 10/15 W, 20/25 W, 30/45 W, 65 W, 100 W, 150 W, 200 W, 300 W and 500 W. A slash rating such as 10/15 W is a single specified rating category, not two different transformer types; interpret it from the standard and datasheet.
6.6 A / 6.6 A
Example 200 W, 6.6 A / 6.6 A: rated 200 W, 6.6 A primary, 6.6 A secondary. For a 6.6 A primary series circuit.
20 A / 6.6 A
Example 200 W, 20 A / 6.6 A: 20 A primary, 6.6 A secondary. It cannot simply replace a 6.6 / 6.6 A unit because the primary current differs.
20 A / 20 A
Some types, such as specified 300 W and 500 W units, have both windings at 20 A. They differ from 20 A / 6.6 A types. Types with a 6.6 A primary and a 20 A secondary (L-830/831-8 and -12) also exist, so never assume primary and secondary currents are equal. Always read the complete rating.
Low wattage
10/15 W and 20/25 W exist because not every fitting needs 100 W or 200 W. Do not use a 100 W unit just because it is on the shelf.
Rule
- Primary current must match the actual AGL series circuit
- Transformer = Application + Wattage + Primary current + Secondary current + Frequency + Standard
ELECTRICAL CHARACTERISTICS
AC 150/5345-47C specifies minimum power factor, minimum efficiency, secondary full-load and short-circuit current, load resistance and maximum secondary open-circuit RMS voltage.
Power factor
Power factor = Real power ÷ Apparent power. A high value reduces unnecessary apparent-power demand. The FAA table gives a minimum of 0.95 for the listed types.
Efficiency
Efficiency (%) = Output ÷ Input × 100. Minimums of 70, 80, 85 or 90% depending on type: for example 90% for several 200 W, 300 W and 500 W types and 70% for the 10/15 W and 20/25 W types.
Capacity margin
The standard requires enough capacity for lamp ageing, secondary lead losses and contact losses, so nominal lamp wattage alone is not always enough.
Open and short secondary
The transformer is designed for indefinite operation with short- or open-circuit secondary under the specified primary conditions. This is a reason AGL units differ from ordinary transformers. Never short an energised transformer intentionally. An open secondary can still carry a specified maximum open-circuit voltage (tens of volts, up to roughly 70 V RMS on the larger types), so treat the secondary leads of an energised circuit as live.
Losses
Copper loss (Pcu = I²R, winding resistance), core loss (magnetic operation) and further losses from leakage flux and connections all become heat. Excessive temperature accelerates insulation ageing.
CONSTRUCTION
An AGL isolating transformer is not an ordinary indoor transformer. AC 150/5345-47C requires:
- Electrically separate primary and secondary coils, insulated from each other and from the core
- A core providing the magnetic path
- A permanently sealed, watertight case
- Molded connectors on primary and secondary leads
- Tightly wound, secured windings before molding
- No internal air pockets in the encapsulated assembly
Case and encapsulation
- Minimum black cross-linked polychloroprene, or equivalent or better materials such as certain TPE or TPV
- Withstands sunlight, oil, gasoline, water, runway deicing fluids and acidic/alkaline soils
- Protects core, windings and internal connections from moisture, dirt, chemicals and mechanical damage
Environment
- Continuous outdoor operation approximately −55 °C to +65 °C
- Operates buried in the ground and submerged in water
- Meets the specification in any orientation (upright or on any side)
LEADS AND CONNECTORS
The FAA arrangement has two single-conductor primary leads and one two-conductor secondary lead (primary H1, H2; secondary X1/X2).
| Lead | FAA arrangement (L-830 / L-831) |
|---|---|
| Primary | One lead with a Style 2 plug, one with a Style 9 receptacle; minimum No. 8 AWG (about 8.4 mm²; 6 mm² is a different, smaller size, so confirm the metric equivalent on the datasheet); minimum 5,000 V insulation; specified lead length. H1 → plug, H2 → receptacle |
| Secondary | Two-conductor cable, No. 12 or 14 AWG, minimum 2 mm², 600 V; L-823-style connector with specified polarity; about 48 in ± 3 in total extension in the FAA configuration |
Primary cable → PLUG → H1 [TRANSFORMER] H2 → RECEPTACLE → Primary cable
│
X1/X2 secondary lead → connector → fixtureAC 150/5345-47C references AC 150/5345-26 for L-823 plug and receptacle connectors, so transformer, connector, cable and fixture must be treated as one compatible system. Verify the actual connector product against the applicable specification and project requirement.
How they sit in the circuit
Each transformer normally supplies one fitting: transformer → secondary cable → AGL connector → fixture. The transformers are part of the continuous primary series loop.
50 Hz VS 60 Hz
50 Hz
Use the applicable L-831.
60 Hz
Use the applicable L-830.
For projects on a 50 Hz electrical system, verify frequency from the airport electrical design, project specification, CCR documentation, transformer datasheet and approved drawings. Do not assume frequency from the country alone.
SELECTION METHOD
- Identify the fitting. Runway edge, centreline, taxiway, approach, PAPI, sign or other equipment.
- Determine fitting power. For example 15, 45, 100 or 200 W.
- Identify primary circuit current. 6.6 A or 20 A.
- Determine secondary requirement. Secondary current, voltage and fixture requirements.
- Check frequency. 50 Hz or 60 Hz.
- Select the applicable type. L-831 for 50 Hz, L-830 for 60 Hz.
- Verify the standard. FAA, ICAO/project requirement, national authority, airport specification, manufacturer documentation.
Worked examples (50 Hz)
| Fixture and circuit | FAA type family |
|---|---|
| 15 W, 6.6 A | L-831-16: 10/15 W, 6.6 / 6.6 A |
| 45 W, 6.6 A | L-831-1: 30/45 W, 6.6 / 6.6 A |
| 100 W, 6.6 A primary | L-831-4: 100 W, 6.6 / 6.6 A |
| 100 W, 20 A primary | L-831-5: 100 W, 20 / 6.6 A |
| 150 W, 6.6 A / 20 A primary | L-831-18 / L-831-19 |
| 200 W, 6.6 A primary | L-831-6: 200 W, 6.6 / 6.6 A |
| 200 W, 20 A primary | L-831-7: 200 W, 20 / 6.6 A |
Final selection must match the actual fitting and approved project specification.
REPLACEMENT RULE AND LED FIXTURES
When replacing a failed transformer, do not ask only "what wattage was installed?" Ask what type, frequency, primary current, secondary current, wattage, connector, fitting, standard, project specification and manufacturer requirements apply.
An incorrect transformer can give incorrect fixture current, reduced or abnormal intensity and poor photometric performance. Replacing 45 W lamps with low-power LED fixtures can also leave transformers and the CCR lightly loaded, so re-check circuit loading (see Note 07).
NAMEPLATE, INSPECTION AND HANDLING
Nameplate (AC 150/5345-47C markings)
- L-830 or L-831 specification and transformer rating
- Frequency
- Manufacturer part number, manufacturer / trademark, country of origin
- Primary and secondary amperes
- Primary voltage rating information
L-831 200 W – 50 Hz Primary: 6.6 A Secondary: 6.6 A Manufacturer: XXXXX Part No.: XXXXX Country of Origin: XXXXX
Case inspection before installation
- Cracks, blisters, holes, cuts, deep abrasions
- Damaged leads or connectors, loose connector parts
- Deformation, poor molding, contamination
Connector inspection
- Plug body, receptacle body, contacts, seals
- Cable sheath, mechanical condition, connector fit
- Keep mating surfaces clean and protected
Protective caps. The specification requires water-resistant caps on the lead connectors. Keep them on during transport, storage, handling and installation to protect mating parts from dirt, moisture and contamination.
Handling. Do not throw transformers, drag them by cables, force connectors, cut connector boots, damage the case, pull leads unnecessarily or let conductive contamination reach connectors. The FAA shock and lead-rigidity tests show that the design is durable, but they are qualification tests, not handling procedures.
Storage. Keep connectors capped, avoid mechanical damage, do not cut or bend leads, keep identification visible and follow manufacturer recommendations.
INSTALLATION
AGL LIGHT
│ secondary
┌───────────┐
│ Isolation │
│Transformer│
└───────────┘
│H1 H2│
────────┴──────────┴────────
PRIMARY SERIES CABLEInstallation depth, pit arrangement and cable routing must follow approved project drawings and manufacturer requirements.
Verify before installing
- Correct type, wattage, frequency
- Correct primary and secondary current
- Correct connectors, cable and fixture
- Correct identification
- No physical damage
- Connector protection removed only when required
During installation
- Connectors clean and correctly mated
- Cable properly routed
- No excessive stress on leads
- Test completed as required
- Identification recorded
WATER INGRESS AND INSULATION
Moisture is one of the main enemies of an AGL electrical system. It causes reduced insulation resistance, leakage current, corrosion, tracking, connector deterioration, transformer failure and circuit faults, which is why sealed construction and insulation testing are critical.
Insulation must separate primary from secondary, primary from core/ground, and secondary from core/ground. AC 150/5345-47C contains specific insulation-resistance and leakage-current requirements. The primary winding is specified for 5,000 V and the secondary for 600 V; this is part of the insulation design, not the normal operating voltage.
QUALIFICATION TESTING
Qualification establishes that the design complies. AC 150/5345-47C specifies tests on three samples of each unit submitted. Do not confuse this with routine production testing of individual units.
The 20-cycle insulation test
Each cycle involves connector installation, heating operation, water immersion, water soaking and insulation-resistance measurement, with connectors remaining mated throughout.
| Stage | Requirement |
|---|---|
| Heating | Minimum 6 hours at room temperature with rated primary current, secondary open-circuited, mating connectors installed |
| Immersion | Transformer, leads and connectors fully submerged, then insulation resistance measured (tests the whole transformer + lead + connector system wet) |
| Soak | Minimum 12-hour water soak within the cycle |
| Insulation resistance | DC test voltage applied for one minute under water conditions; minimum resistance or maximum leakage-current criteria |
FAA insulation values, transformers up to 150 W
| Winding | Test voltage | Minimum insulation resistance | Or maximum leakage |
|---|---|---|---|
| Primary | 15 kV DC | 7,500 MΩ | 2 µA |
| Secondary | 5 kV DC | 2,500 MΩ | 2 µA |
Other qualification tests
- Temperature rise at rated load, short circuit and open circuit
- Shock: two drops from about 6 ft (about 1.8 m) onto smooth hardwood, in orientations that challenge case, core and windings
- Lead rigidity: lead attachment secure after shock and mechanical loading
Production tests (each unit)
- Current-ratio test at rated frequency, rated primary current and rated secondary load
- Insulation testing
- Void inspection: voids are grounds for rejection (they can create moisture paths, stress concentrations and thermal problems)
The current-ratio test matters because AGL series circuits are current-controlled: the transformer must deliver the intended secondary current, which affects light output, loading, reliability and photometry.
FIELD TESTS: CONTINUITY VS INSULATION
| Test | What it shows | Limit of the test |
|---|---|---|
| Continuity | Whether a conductive path exists; finds open winding, broken lead, open connector, broken cable | Does not prove health: a unit can pass continuity and still have low insulation resistance, wrong output, turn-to-turn faults, thermal problems or moisture ingress |
| Insulation resistance | Whether insulation prevents unwanted leakage (primary → ground, secondary → ground, primary/secondary relationship) | Method and voltage must follow the approved procedure |
| Dielectric withstand | Whether insulation withstands an applied test voltage without breakdown | Test voltage, duration and method come from the standard and approved procedure |
| Current / ratio | Whether secondary current meets the specified characteristics | Needs rated frequency, primary current and secondary load |
Beginner mistake
- Continuity checks whether a conductive path exists
- Insulation resistance checks whether unwanted leakage is adequately prevented
- A good transformer must satisfy both
FAULT MODES AND FAULT-FINDING
| Fault mode | Effect |
|---|---|
| Open primary winding, lead or connector | Breaks the series loop: the whole circuit goes out and the CCR's open-circuit protection normally operates |
| Shorted primary turns | That unit's output falls or is lost while the loop usually stays complete; the CCR keeps regulating current |
| Secondary winding fault | May affect one individual fixture |
| Insulation breakdown | Leakage or circuit faults |
| Water ingress | Reduced insulation resistance |
| Connector failure | Intermittent or no output |
| Lead damage | Open or high-resistance connection |
| Mechanical damage | Compromised sealing or internal components |
| Thermal damage | Excess loading or internal fault |
Troubleshooting sequence
Do not replace the transformer without diagnosis.
| Symptom | Possible cause |
|---|---|
| One fixture OFF | Fixture / secondary / transformer |
| Many fixtures OFF | CCR, primary cable, primary series circuit, multiple transformers: investigate the common upstream system |
| Low fixture output | Wrong transformer, secondary loss, fixture issue |
| Repeated circuit fault | Primary or insulation fault |
| Low insulation resistance | Moisture, damage, insulation breakdown |
| Connector heating | High contact resistance |
| Open circuit | Broken lead, winding or connection |
| Abnormal secondary current | Wrong type, load or internal fault |
| Swelling or physical damage | Thermal, mechanical or environmental issue |
Insulation failure
Symptoms: low insulation resistance, high leakage current, CCR alarm or trip, circuit instability, intermittent operation, water-related fault indications. Likely causes: moisture ingress, damaged case or lead, connector contamination, internal breakdown.
High-resistance connector
This can end in connector damage, secondary voltage drop and fixture failure. A connector that physically fits is not necessarily a good electrical connection; the same applies to secondary cable loss (I²R), where longer or higher-resistance cable increases loss.
QA, FAT AND DOCUMENTATION
Typical documentation
- Datasheet and technical specification
- Type / qualification certificate
- Routine, insulation and ratio/current test reports
- Calibration certificates for test equipment
- Material / compliance documents
- Manufacturer's declaration
- Inspection report, packing / identification records
FAT may include
- Identification: type, wattage, frequency, currents
- Electrical: currents, ratio, insulation resistance, dielectric withstand where specified
- Physical: dimensions, weight, case, leads, connectors, markings
- Documentation: reports, certificates, drawings, datasheet
Actual document requirements depend on the project. Site receipt sequence: check model → wattage → frequency → primary current → secondary current → connectors → case → leads → test if required → install.
COMPARISONS
Transformer vs CCR
| Isolation transformer | CCR |
|---|---|
| Individual field component | Main series-circuit regulator |
| Provides electrical isolation | Controls series current |
| Transfers power | Supplies controlled current |
| Often one per field load | One CCR can feed a complete series circuit |
| Near the field fitting | Usually in the electrical / AGL equipment area |
AGL transformer vs ordinary transformer
| AGL isolation transformer | Ordinary distribution transformer |
|---|---|
| Designed for airport series circuits | General electrical distribution |
| Compact sealed field unit | Often larger equipment |
| Designed for underground / wet conditions | Installation varies |
| Specialised current / load characteristics | General voltage-based application |
| AGL connector system | Standard electrical terminals |
| Airport lighting standards | General electrical standards |
An ordinary transformer may not be suitable because AGL units must handle series-circuit operation, constant-current supply, high primary insulation, outdoor/buried installation, water immersion, mechanical stress, deicing chemicals, connector compatibility and fixture-specific power levels.
Memory rule
- CCR controls the current
- Transformer isolates and transfers the power
COMMON MISTAKES
1. Selecting only by wattage
"Need 200 W, buy any 200 W transformer" is wrong. Check wattage, primary and secondary current, frequency and standard.
2. Ignoring frequency
50 Hz is not 60 Hz.
3. Mixing 6.6 A and 20 A
A 20 A-primary unit is not automatically interchangeable with a 6.6 A-primary unit.
4. Ignoring connector compatibility
A correct electrical rating with an incompatible connector is still an incorrect installation.
5. Ignoring environmental protection
Underground installation still needs proper sealing of the complete connection system.
6. Treating continuity as complete testing
Continuity does not confirm insulation or performance.
7. Installing a damaged transformer
Investigate serious cracks, damaged leads or damaged connectors first.
FINAL SELECTION CHECKLIST
Electrical
- Wattage
- Primary and secondary current
- Frequency
- Voltage / insulation rating
- Efficiency
- Power factor
Mechanical and connectors
- Case construction, dimensions, weight
- Lead length and protection
- Primary plug and receptacle
- Secondary connector, cable size, compatibility
Environment
- Watertight
- Underground and water-immersion suitable
- Temperature range
- Deicing-fluid and chemical exposure
Testing and documents
- Ratio/current and insulation tests
- Dielectric test if specified
- Temperature-rise qualification and routine test
- Datasheet, certificates, calibration, FAT records
The practical engineer's rule
- Ask "What is the complete rating?", not "How many watts?"
- What wattage, frequency, primary current, secondary current, fixture, connector and standard?
QUICK REVISION
Remember
- L-830 = 60 Hz · L-831 = 50 Hz
- 200 W: L-830/831-6 = 6.6 / 6.6 A · L-830/831-7 = 20 / 6.6 A
- Primary 5,000 V · secondary 600 V (FAA rating)
- Case: permanently sealed, watertight, no internal air pockets
- Qualification = design (3 samples); production = every unit (current ratio, insulation, voids)
- Continuity ≠ insulation resistance
Master flow
AGL ISOLATION TRANSFORMER
┌───────────────────┼───────────────────┐
PRIMARY CORE + COILS SECONDARY
6.6 / 20 A Isolation · sealed 6.6 / 20 A
case · encapsulation
└──────────── POWER TRANSFER ───────────┘
│
AGL FIXTUREEXAM / INTERVIEW QUESTIONS
What is an AGL isolation transformer?
A specialised series-to-series transformer that electrically isolates and supplies an individual airport lighting fitting from the primary series circuit.
What is the difference between L-830 and L-831?
L-830 is 60 Hz; L-831 is 50 Hz.
Why is an isolation transformer used in AGL?
To isolate the individual fixture from the primary series circuit while transferring the required power.
What is a 200 W 6.6/6.6 A transformer?
One rated 200 W with 6.6 A primary and 6.6 A secondary characteristics.
What is a 200 W 20/6.6 A transformer?
One rated 200 W with 20 A primary and 6.6 A secondary characteristics.
Can a 6.6/6.6 A transformer replace a 20/6.6 A transformer?
Not simply. The primary current must match the actual series-circuit design.
Does wattage alone identify a transformer?
No. Also verify current, frequency, secondary characteristics, application and standard.
Which type is used for 50 Hz? For 60 Hz?
L-831 for 50 Hz; L-830 for 60 Hz.
Why is the transformer case sealed?
To protect against water and the environmental exposure of airport field installation.
Why are AGL transformers suitable for underground installation?
Their construction and sealing are designed for outdoor, buried and water-exposure conditions under the applicable specification.
What is the purpose of the primary winding?
To connect the transformer into the series circuit and receive the controlled primary current.
What is the purpose of the secondary winding?
To supply the individual AGL fixture with the specified secondary characteristics.
What is the difference between continuity and insulation-resistance testing?
Continuity verifies a conductive path; insulation resistance verifies that insulation prevents unwanted leakage.
Why is connector condition important?
A poor connector causes resistance, heating, voltage drop, intermittent operation and eventual failure.
What is the basic AGL chain?
CCR → Primary Cable → Isolation Transformer → Secondary Cable → AGL Fixture.
FINAL STUDY TAKEAWAY
The isolating transformer is the critical interface between the high-voltage primary series circuit and the individual lighting fitting. Remember: primary on the CCR-controlled loop; secondary to the fitting; isolation between them; wattage matched to the load; primary and secondary current ratings; frequency (L-830 / L-831); environment; compatible connectors; testing; and the whole system of CCR, cables, transformer, connector, fixture and photometry.
Transformer knowledge = Wattage + Primary current + Secondary current + Frequency + Insulation + Connectors + Environment + Testing + Compliance.
ENGINEERING & EXPERT NOTES
Suspect the Leads and Connectors First
Fault FindingIn practice, many apparent transformer failures sit in the leads or moulded connectors. Check and test them before condemning the unit.
Rating Follows the Fixture Load
SelectionChoose the rating from the connected load with sensible margin, and recheck it whenever the fixture type changes, especially in LED conversions.
Insulation Decline Usually Starts With Moisture
Water IngressA falling insulation trend in a wet pit points to the environment as well as the transformer. Fix the entry path or the replacement will age the same way.
Label and Record the Type at Every Location
RecordsFitting the wrong rating or type during a night repair is an avoidable error. Keep nameplate details on the register and in stores.
REFERENCES & FURTHER READING
These notes are a study aid. Verify details against the primary sources below.
| # | Source | Use it for |
|---|---|---|
| 1 | FAA AC 150/5345-47C – Specification for Series to Series Isolation Transformers for Airport Lighting Systems | L-830/L-831 types, electrical characteristics, construction, leads, environment, qualification and production testing. Confirm the current edition on the FAA advisory circular site. |
| 2 | FAA AC 150/5345-26 – Specification for L-823 Plug and Receptacle, Cable Connectors | Connector requirements referenced by the transformer specification. |
| 3 | Note 07: Constant Current Regulators | The series-circuit current source the transformer connects to. |
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