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MILDTL 38999 S III
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MIL-DTL-38999
Features and Application
Series III
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Features and Application
MIL-DTL-38999 Series III is the newest cylindrical connector
designed for highest performance capabilities used in both
general purpose and severe environment applications.
These connectors feature an improved one-turn coupling
system, utilizing self-locking acme thread. Acme threads
provide coupling durability, while thicker wall sections and
greater coupling surface area improve strength and shock
resistance. Blunting of the threads on both receptacle and
plug coupling nut eliminates cross threading.
Elongated mounting holes permit the Series III Connector to
intermount with various existing Mil-spec flange mounted
receptacles, giving it a design replacement advantage.
Wall mount receptacle, jam nut receptacle and straight
self-locking RFI plug are offered in 9 shell sizes and 54 insert
arrangements utilizing M39029 contacts in sizes 22D, 20, 16,
12, 10 power and 8 twinax.
These connectors are available in wide range of shell materials
and finishes. Aluminum shells are offered in electroless nickel
and olive drab cadmium. Other finishes such as anodic and
zinc nickel are available upon request to commercial callouts
only. In addition, we offer stainless steel shells (both passivated
and electro-deposited nickel plated) with firewall inserts, and
for highly corrosive environments, nickel-aluminum-bronze
shells with standard environment-resisting inserts (commer-
cial callouts only).
MIL-STD-1560 Insert Arrangements – Series III connectors
use insert patterns and contacts common to Series I,
making for an easy transition from bayonet to triple-lead,
acme-thread, self-locking coupling.
Metal-to-Metal Bottoming – This feature precludes relative
shell-to-shell motion, which may result in ordinary connector
wear and moisture entrapment.
Lockwiring Eliminated – Self-locking quick coupling plug
eliminates the need for lockwiring.
Firewall Capability - Stainless steel shells in both K and S
firewall classes are offered.
Universal I/R Tool – A single, expendable plastic tool is used
for both insertion and removal of contacts.
Scoop-Proof Design Recessed pins in elongated shells
minimize the possibility for contact damage. In a blind
mating application, mating shells cannot “scoop” the pins,
and cause a shorting or bending of contacts.
Closed-Entry Socket Insert Hard dielectric socket face
has lead-in chamfers for positive alignment of pins (even
partially bent within pre-established limits) with sockets.
Interfacial Pin Insert Seal Raised moisture barriers
around each pin, which mate into lead-in chamfers of
hard face socket insert, provide individual contact sealing.
Interfacial seal is never touched by service tools.
Elastomer Wire Sealing Grommet Sealing over a wide
range of wire diameters is assured by a triple wire seal in
each cavity at the rear of the connector.
Superior Contact Stability Rear release crimp contact
system features a stamped beryllium-copper retaining clip
captivated by molded-in shoulders of each contact cavity in
the insulator. A rear-inserted M81969 plastic tool expands
the tines beyond the shoulder, releasing the contact.
Metric Accessory Thread – Metric thread results in
additional wall thickness giving greater strength and shock
resistance.
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MILDTL 38999 S III
MIL-DTL-38999
Performance Specifications
Series III
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Performance Specifications
Operating Temperature Range
Classes F, K, S and BZ*: -65°C to +200°C (-85°F to +392°F)
Classes W and ZC*: -65°C to +175°C (-85°F to +347°F)
Material and Finish Data (Class)
F aluminum shell, electroless nickel finish
K stainless steel shell, passivated, firewall
S stainless steel shell, electrodeposited nickel, firewall
W aluminum shell, olive drab cadmium over nickel base
BZ* aluminum nickel bronze shell, std insert
Z* aluminum shell, zinc nickel finish
Corrosion Resistance
Classes K, W, BZ* and Z* withstand 500-hour salt spray.
Classes F and S withstand 48-hour salt spray.
Durability
Minimum of 500 mating cycles.
Fluid Resistance
Connectors resist specified immersions in MIL-PRF-7808,
MIL-PRF-23699, MIL-PRF-5606, M2-V Chevron oil, Coolanol
25, MIL-DTL-83133 (JP-8), MIL-DTL-5624 (JP-4, JP-5),
SAE-AMS1424 Type I, and other solvents and cleaning agents.
Shielding Effectiveness
RFI and EMI attenuation at the specified frequencies meet
the requirements of MIL-DTL-38999.
RFI shielding effectiveness of mated connectors with RFI
backshells is measured in a triaxial radio frequency leakage
fixture.
EMI shielding effectiveness is measured at the interface
of mated connectors and tested by the mode-stirred
technique specified in method 3008 of MIL-STD-1344.
Voltage Rating
Environmental Seal
Wired, mated connectors with specified accessories
attached, shall meet the altitude-immersion test specified in
MIL-DTL-38999.
Shell-to-Shell Conductivity
Maximum potential drop shall not exceed:
Classes F and S = 1.0 millivolt.
Class W = 2.5 millivolts, Class K = 10.0 millivolts
Shock and Vibration Requirements
Wired, mated connectors shall not be damaged, nor shall
there be a current interruption longer than one microsecond
when subjected to the following:
Shock
Pulse of approximate half sine wave of 300 G ±15 percent mag-
nitude with duration of 3 ±1 milliseconds applied in three axes.
High Impact Shock
When mounted as specified in MIL-S-901, grade A, a drop
of a 400 lb. Hammer from 1 foot, 3 feet and 5 feet applied to
connector in three axes, totaling nine impacts.
Vibration
Wired and mated connectors withstand the following
vibration levels:
Sine vibration where connector samples with simulated
accessory load are subjected to simple harmonic motion
from 10 to 2,000 Hz in three mutually perpendicular axes,
in 20 minute sweeps, for 12 hours in each axis at velocity of
254 mm/sec from 10-50 Hz, displacement of 1.5 mm from
50-140Hz and acceleration of 60G from 140-2,000Hz.
Random Vibration per MIL-STD-1344, method 205,
test condition V at ambient temperature and test
condition VI, Letter “J” at elevated temperature.
* Not on QPL, can be supplied to Aero-Electric part number only.
Service
Rating
Suggested Operating Voltage Test Voltage Test Voltage Test Voltage Test Voltage
(Sea Level) Sea Level 50,000 Ft. 70,000 Ft. 100,000 Ft.
AC (RMS) DC V RMS V RMS V RMS V RMS
M 400 550 1300 550 350 200
N 300 450 1000 400 260 200
I 600 850 1800 600 400 200
II 900 1250 2300 800 500 200
Note: The establishment of electrical safety factors is left
entirely to the designer, as he is in the best position to know
exactly what peak voltages, switching currents, transients, etc.,
can be expected in a particular circuit.
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MILDTL 38999 S III
MIL-DTL-38999
Part Number Development
Series III
Military and Aero-Electric Part Number Development
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* Not on QPL, can be supplied to Aero-Electric part number only.
Note 1: Each connector is furnished with contacts unless
ordered less contacts (L/C) as follows: One spare contact for
inserts requiring 2 through 26 of each contact and two
spares for inserts with 27 or more contacts, and a minimum
of one sealing plug up to 10% of the number contacts.
Spare Coax and Twinax contacts are not supplied. One
insertion/extraction tool for each contact size is also included.
Note 2: Proper part number marking has no “0” in front
of single digit layout. Example: JD38999/20WB5SN. “N” for
normal is included. In addition, J or JAN must be marked
immediately in front of MIL part number.
Mil. Prefix D38999/ 20 W C 35 P N
Aero Prefix AE3 20 W C 35 P N -340
Shell Type (Specification Sheet Number)
20 = Wall mount receptacle
24 = Jam nut receptacle
26 = Self-locking, RFI grounding plug
Class (Material & Finish)
F= Aluminum shell, electroless nickel finish
W= Aluminum shell, olive drab cadmium over electroless nickel base
K= Stainless steel shell, passivated, with firewall insert
S= Stainless steel shell, electrodeposited nickel, with firewall insert
BZ* = Aluminum nickel bronze shell with standard insert (Aero p/n only)
Z* = Aluminum shell, zinc nickel plating (Aero p/n only)
Shell Size
A, B, C, D, E, F, G, H or J
Insert Arrangement
See pages 15 thru 19
Contact Style
P= Pin
S= Socket
A= Pin connector less pins (with intent to use non-std pin contacts)
B= Socket connector less sockets (with intent to use non-std socket contacts)
Polarization (Keying)
N= Normal (Included in part number)
A, B, C, D, or E
Modification (applies to Aero part numbers only)
01 = Less contacts (is not marked on the part)
340 = Connector kitted with M85049/14-XXX
341 = Connector kitted with M85049/38-XXX straight clamp
342 = Connector kitted with M85049/39-XXX right angle clamp
Consult factory for other modifications
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MILDTL 38999 S III
D38999/20
Wall Mounting Receptacle
AE320
Triple Start Threaded Coupling, Crimp Removable, Rear Release, Scoop-Proof
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BLUE COLOR BAND
(REAR RELEASE)
B
4 MINOR KEYWAYS
E
C
D
LOCKING INDICATOR BAND
COLOR: RED
F
MATING THREAD
MASTER KEYWAY G
MAX
31.50(1.240)
MAX
2.16(.085) MAX
GROMMET EXTENSION
J NUMBER OF TEETH
K ACCESSORY THREAD
7.11(.280)
MIN FULL THREAD
H MAX
A
[ L
MAX
GROMMET
Page 38 Completed Part Number
Page 44 Contacts, Sealing Plugs and Tools
Pages 17–19 Insert Arrangements
Page 37 Performance Specifications
Pages 15, 16 Insert Availability and Contact Information
Page 42 Polarization
Note 1: “K” Accessory Thread for AE320 is same as AE326
(“D” Accessory Thread) on page 41.
Note 2: “F” Mating Thread for AE320 is same as AE326
(“E” Mating Thread) on page 41 except it is Class 2A.
Note 3: Maximum Grommet Extension for insert layouts
incorporating size 8 and 10 contacts = 5.95(.234).
Shell
Size
A B C D E G H J L
No. of
±.012 ±.30 (TP) (TP) ±.008 ±.20 ±.008 ±.20 Maximum Maximum Teeth Maximum
inch mm inch mm inch mm inch mm inch mm inch mm inch mm inch mm
A .937 23.80 .719 18.26 .594 15.09 .216 5.49 .128 3.25 .820 20.83 .098 2.50 12 .299 7.59
B 1.031 26.20 .812 20.62 .719 18.26 .194 4.93 .128 3.25 .820 20.83 .098 2.50 16 .427 10.85
C 1.126 28.60 .906 23.01 .812 20.62 .194 4.93 .128 3.25 .820 20.83 .098 2.50 20 .541 13.74
D 1.220 31.00 .969 24.61 .906 23.01 .173 4.39 .128 3.25 .820 20.83 .098 2.50 24 .666 16.92
E 1.311 33.30 1.062 26.97 .969 24.61 .194 4.93 .128 3.25 .820 20.83 .098 2.50 28 .791 20.09
F 1.437 36.50 1.156 29.36 1.062 26.97 .194 4.93 .128 3.25 .820 20.83 .098 2.50 32 .897 22.78
G 1.563 39.70 1.250 31.75 1.156 29.36 .194 4.93 .128 3.25 .790 20.07 .126 3.20 36 1.022 25.96
H 1.689 42.90 1.375 34.93 1.250 31.75 .242 6.15 .154 3.91 .790 20.07 .126 3.20 40 1.147 29.13
J 1.811 46.00 1.500 38.10 1.375 34.93 .242 6.15 .154 3.91 .790 20.07 .126 3.20 44 1.272 32.31