PartsTable TECHNICAL DATA SHEET
JULY 2026Technical Data Sheet

4991-027Meter,electrical Frequency

Jewell Instruments Llc · NSN 6625-00-879-4101 · FSC 6625 · No Item Name Available
Verified by PartsTable
NSN 6625-00-879-4101 — this item is cataloged by the U.S. Government under National Stock Number 6625-00-879-4101. Primary manufacturer part number: 4991-027.
Features
  • Meter,electrical Frequency — FSC 6625
  • Mounting Stud Length: 1.469 INCHES NOMINAL IN
  • Center to Center Distance Between Mounting Facilities Parallel to Width: 3.376 INCHES NOMINAL IN
  • Installation Design: PANEL
  • Frequency Response Range: +350.000 TO 450.000 HERTZ
  • Meter Body Diameter Behind Mounting Flange: 4.000 INCHES MAXIMUM IN
  • Meter Depth Behind Mounting Flange: 3.875 INCHES MAXIMUM IN
  • Mounting Facility Type and Quantity: 4 THREADED STUD(S)
Applications
  • Industrial maintenance and repair
  • Government and military logistics
  • Equipment overhaul and refurbishment
General Description

The Meter,electrical Frequency, cataloged under National Stock Number 6625-00-879-4101, is classified within Federal Supply Class 6625 (No Item Name Available) of the Instruments and Laboratory Equipment group. The primary manufacturer of record is Jewell Instruments Llc. Government technical data includes 27 verified specifications, sourced from the Federal Logistics Information System (FLIS). This item has 6 commercial cross-references from 4 manufacturers, enabling identification through both NSN and commercial part number lookups. 12 verified substitutes exist in the FLIS interchangeability database. Current acquisition status: Active. Unit of issue: EA.

Technical Specifications
ParameterValue
NSN6625-00-879-4101
Primary Part Number4991-027
Item NameMeter,electrical Frequency
FSC / FSG6625 / 66 — No Item Name Available
ManufacturerJewell Instruments Llc
StatusACTIVE
Mounting Stud Length1.469 INCHES NOMINAL IN
Center to Center Distance Between Mounting Facilities Parallel to Width3.376 INCHES NOMINAL IN
Installation DesignPANEL
Frequency Response Range+350.000 TO 450.000 HERTZ
Meter Body Diameter Behind Mounting Flange4.000 INCHES MAXIMUM IN
Meter Depth Behind Mounting Flange3.875 INCHES MAXIMUM IN
Mounting Facility Type and Quantity4 THREADED STUD(S)
Circuit Attachment Method and Quantity3 SOLDER STUD
Features ProvidedZERO ADJUSTER
Style DesignatorRECTANGULAR FLUSH MTG
FSC Application DataTEST SET,ELECT. EQUIP.
Mounting Stud Diameter0.250 INCHES NOMINAL IN
Nuclear Hardness Critical FeatureNONHARDENED
Measurement Range+350.0 TO 450.0 HERTZ SINGLE INDICATOR SINGLE RANGE
Center to Center Distance Between Mounting Facilities Parallel to Length3.376 INCHES NOMINAL IN
Mounting Arrangement StyleFOUR HOLE/STUD RECTANGULAR/SQUARE
Indicator TypeDIAL W/POINTER
Furnished Items and QuantityIMPEDOR 1
Mounting Stud Length1.469 INCHES NOMINAL IN
Center to Center Distance Between Mounting Facilities Parallel to Width3.376 INCHES NOMINAL IN
Installation DesignPANEL
Frequency Response Range+350.000 TO 450.000 HERTZ
Meter Body Diameter Behind Mounting Flange4.000 INCHES MAXIMUM IN
Meter Depth Behind Mounting Flange3.875 INCHES MAXIMUM IN
Mounting Facility Type and Quantity4 THREADED STUD(S)
Circuit Attachment Method and Quantity3 SOLDER STUD
Features ProvidedZERO ADJUSTER
Lifecycle & Compliance
Acquisition StatusACTIVE
HAZMATNo
Shelf Life Code0
Criticality CodeN
Unit of IssueEA
SMR CodeJN
Weight9.1700 lbs
Cube1.3542 cu ft
Verified Substitutes 12
5310-00-050-33235B2383 INTERCHANGEABLE
Nut,self-Locking,hexagon
Caterpillar Inc Div Caterpillar Defense
5935-00-058-43477517B INTERCHANGEABLE
Connector,receptacle,electrical
Hubbell Incorporated (delaware) Dba Wiring Device-Kellems Division
2805-00-088-3337110-0881 INTERCHANGEABLE
Valve,poppet,engine
Cummins Power Generation Inc.
5905-00-106-3818R913 INTERCHANGEABLE
Resistor Network,fixed,wire Woun
Shallcross Inc
5310-00-127-79591998 INTERCHANGEABLE
Washer,key
Westinghouse Air Brake Technologies Corp Dba Westinghouse Air Brake Technologies Corp
5340-00-200-27371756320 INTERCHANGEABLE
Clamp,loop
Naval Ship Systems Command
6810-00-264-8957 INTERCHANGEABLE
Methyl Red
4930-00-277-9525 INTERCHANGEABLE
Lubricating Gun,handheld
2520-00-358-38751201 INTERCHANGEABLE
Cover Assembly,clutch
Sachs-Boge of America
4030-00-407-6512 INTERCHANGEABLE
Hook,guy
Cross-Reference Index
Part NumberManufacturer
758-4-1 Regulators Products Group of Ward Leonard Electric Co Inc (USA)
758-4 Regulators Products Group of Ward Leonard Electric Co Inc (USA)
1998 Jewell Instruments, Llc Dba Modutec Use CAGE Code 33005 for Cataloging (USA)
4991-027 PRIMARY Jewell Instruments Llc (USA)
499-027 Jewell Instruments Llc (USA)
F4AA3 General Electric Co Instrumentation and Computer Service Dept (USA)
Related Parts
5310-00-050-3323INTERCHANGEABLE
NUT,SELF-LOCKING,HEXAGON
5B2383
5935-00-058-4347INTERCHANGEABLE
CONNECTOR,RECEPTACLE,ELECTRICAL
7517B
2805-00-088-3337INTERCHANGEABLE
VALVE,POPPET,ENGINE
110-0881
5905-00-106-3818INTERCHANGEABLE
RESISTOR NETWORK,FIXED,WIRE WOUN
R913
5310-00-127-7959INTERCHANGEABLE
WASHER,KEY
1998
5340-00-200-2737INTERCHANGEABLE
CLAMP,LOOP
1756320
6810-00-264-8957INTERCHANGEABLE
METHYL RED
4930-00-277-9525INTERCHANGEABLE
LUBRICATING GUN,HANDHELD
2520-00-358-3875INTERCHANGEABLE
COVER ASSEMBLY,CLUTCH
1201
4030-00-407-6512INTERCHANGEABLE
HOOK,GUY
5340-01-071-9017INTERCHANGEABLE
RETAINER,HELICAL COMPRESSION SPR
75841
4240-01-186-9769INTERCHANGEABLE
RIOT CONTROL SHIELD
1998

Frequently Asked Questions

What is NSN 6625-00-879-4101?

NSN 6625-00-879-4101 is a Meter,electrical Frequency, manufactured by Jewell Instruments Llc, classified under FSC 6625 (No Item Name Available). Status: active.

What are the part numbers for NSN 6625-00-879-4101?

NSN 6625-00-879-4101 has 6 cross-referenced part numbers: 758-4-1 (Regulators Products Group of Ward Leonard Electric Co Inc), 758-4 (Regulators Products Group of Ward Leonard Electric Co Inc), 1998 (Jewell Instruments, Llc Dba Modutec Use CAGE Code 33005 for Cataloging), 4991-027 (Jewell Instruments Llc), 499-027 (Jewell Instruments Llc) and 1 more.

What NSN replaces 6625-00-879-4101?

There are 12 known substitutes for 6625-00-879-4101: 5310-00-050-3323, 5935-00-058-4347, 2805-00-088-3337 and 9 more. Verify interchangeability with system specifications before substitution.

What are the specifications of 4991-027?

Key specifications for 4991-027: Mounting Stud Length: 1.469 INCHES NOMINAL IN; Center to Center Distance Between Mounting Facilities Parallel to Width: 3.376 INCHES NOMINAL IN; Installation Design: PANEL; Frequency Response Range: +350.000 TO 450.000 HERTZ. 30 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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