PartsTable TECHNICAL DATA SHEET
JULY 2026Technical Data Sheet

21721ARelay,electromagnetic

Bradford Vibrators Co the · NSN 5945-00-443-3911 · FSC 5945 · No Item Name Available
Verified by PartsTable
NSN 5945-00-443-3911 — this item is cataloged by the U.S. Government under National Stock Number 5945-00-443-3911. Primary manufacturer part number: 21721A.
Features
  • Relay,electromagnetic — FSC 5945
  • Nonpile-Up Main Contact Arrangement: 1 POLE, SINGLE THROW, NORMALLY OPEN, MOMENTARY ACTION
  • Time Delay: 60.00 SECONDS NOMINAL FIXED OPERATE TIME
  • Winding Quantity: 1
  • Unthreaded Mounting Hole Diameter: 0.096 INCHES NOMINAL SINGLE MOUNTING FACILITY IN
  • Mounting Facility Type and Quantity: 2 UNTHREADED HOLE(S) SINGLE MOUNTING FACILITY
  • Main Contact Load Current Rating at Maximum Rated Voltage: 100.0 MILLIAMPERES DC RESISTIVE LOAD
  • Duty Type: CONTINUOUS
Applications
  • Circuit control and protection
  • Equipment power management
  • Signal routing
General Description

The Relay,electromagnetic, cataloged under National Stock Number 5945-00-443-3911, is classified within Federal Supply Class 5945 (No Item Name Available) of the Electrical and Electronic Equipment Components group. The primary manufacturer of record is Bradford Vibrators Co the. Government technical data includes 15 verified specifications, sourced from the Federal Logistics Information System (FLIS). This item has 3 commercial cross-references from 2 manufacturers, enabling identification through both NSN and commercial part number lookups. 8 verified substitutes exist in the FLIS interchangeability database. Current acquisition status: Active.

Technical Specifications
ParameterValue
NSN5945-00-443-3911
Primary Part Number21721A
Item NameRelay,electromagnetic
FSC / FSG5945 / 59 — No Item Name Available
ManufacturerBradford Vibrators Co the
StatusACTIVE
Nonpile-Up Main Contact Arrangement1 POLE, SINGLE THROW, NORMALLY OPEN, MOMENTARY ACTION
Time Delay60.00 SECONDS NOMINAL FIXED OPERATE TIME
Winding Quantity1
Unthreaded Mounting Hole Diameter0.096 INCHES NOMINAL SINGLE MOUNTING FACILITY IN
Mounting Facility Type and Quantity2 UNTHREADED HOLE(S) SINGLE MOUNTING FACILITY
Main Contact Load Current Rating at Maximum Rated Voltage100.0 MILLIAMPERES DC RESISTIVE LOAD
Duty TypeCONTINUOUS
Center to Center Distance Between Mounting Facilities Parallel to Length1.000 INCHES NOMINAL SINGLE MOUNTING FACILITY IN
Operating Voltage Rating and Type at Specified Temp21.0 VOLTS DC 25 DEG CELSIUS SINGLE WINDING
Main Contact Maximum Voltage Rating in Volts30.0 DC
Center to Center Distance Between Mounting Facilities Parallel to Width1.000 INCHES NOMINAL SINGLE MOUNTING FACILITY IN
Coil Quantity1
Terminal Type and Quantity5 PIN ALL FUNCTIONS
Mounting Facility PatternDIAGONAL SINGLE MOUNTING FACILITY
Features ProvidedPOLARIZED
Lifecycle & Compliance
Acquisition StatusACTIVE
HAZMATNo
Verified Substitutes 8
5970-00-311-109353173 INTERCHANGEABLE
Insulator,bushing
Inland Mfg Div of General Motors Corp
6105-00-578-62202287-1 INTERCHANGEABLE
Motor,direct Current
Kearfott Corporation Div Guidance and Navigation Division
3120-01-145-91334049256 INTERCHANGEABLE
Bearing Set,sleeve
Chrysler Realty Company Llc Dba Daimler Chrysler
3010-01-230-3971SIZE 50 HTR ELEMENT INTERCHANGEABLE
Insert,flexible Coupling
Lovejoy, Llc Div Lovejoy
4320-01-280-22292287-1 INTERCHANGEABLE
Housing,bearing Inboard
Curtiss-Wright Electro-Mechanical Corporation Div Epd
5340-01-291-7245 INTERCHANGEABLE
Plug,protective,dust and Moistur
5365-01-321-107922871 INTERCHANGEABLE
Spacer,sleeve
Parker Hannifin Corporation Div Hydraulic Systems Division
6520-01-370-756522871 INTERCHANGEABLE
Resin,restorative,dental
Kerr Corporation
Cross-Reference Index
Part NumberManufacturer
21721A PRIMARY Bradford Vibrators Co the (USA)
22871 Bradford Vibrators Co the (USA)
615-7632 Midland-Ross Corp Midtex Div
Related Parts
5970-00-311-1093INTERCHANGEABLE
INSULATOR,BUSHING
53173
6105-00-578-6220INTERCHANGEABLE
MOTOR,DIRECT CURRENT
2287-1
3120-01-145-9133INTERCHANGEABLE
BEARING SET,SLEEVE
4049256
3010-01-230-3971INTERCHANGEABLE
INSERT,FLEXIBLE COUPLING
SIZE 50 HTR ELEMENT
4320-01-280-2229INTERCHANGEABLE
HOUSING,BEARING INBOARD
2287-1
5340-01-291-7245INTERCHANGEABLE
PLUG,PROTECTIVE,DUST AND MOISTUR
5365-01-321-1079INTERCHANGEABLE
SPACER,SLEEVE
22871
6520-01-370-7565INTERCHANGEABLE
RESIN,RESTORATIVE,DENTAL
22871

Frequently Asked Questions

What is NSN 5945-00-443-3911?

NSN 5945-00-443-3911 is a Relay,electromagnetic, manufactured by Bradford Vibrators Co the, classified under FSC 5945 (No Item Name Available). Status: active.

What are the part numbers for NSN 5945-00-443-3911?

NSN 5945-00-443-3911 has 3 cross-referenced part numbers: 21721A (Bradford Vibrators Co the), 22871 (Bradford Vibrators Co the), 615-7632 (Midland-Ross Corp Midtex Div).

What NSN replaces 5945-00-443-3911?

There are 8 known substitutes for 5945-00-443-3911: 5970-00-311-1093, 6105-00-578-6220, 3120-01-145-9133 and 5 more. Verify interchangeability with system specifications before substitution.

What are the specifications of 21721A?

Key specifications for 21721A: Nonpile-Up Main Contact Arrangement: 1 POLE, SINGLE THROW, NORMALLY OPEN, MOMENTARY ACTION; Time Delay: 60.00 SECONDS NOMINAL FIXED OPERATE TIME; Winding Quantity: 1; Unthreaded Mounting Hole Diameter: 0.096 INCHES NOMINAL SINGLE MOUNTING FACILITY IN. 18 total characteristics are documented in the Federal Logistics Information System.

Validated with multiple authoritative sources, including Government, OEM, and Certified sources.
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