ATQR3 Equivalent & Substitute Parts Reference

Part Overview

The ATQR3 is a CC class cartridge fuse rated for 3A at 600V with slow-blow response characteristics, manufactured by Mersen USA Newburyport-MA L.L.C. This fuse is designed for electrical and industrial applications requiring transformer protection and circuit protection in AC systems. The part maintains active product status with 652 units in current inventory. Substitute parts are identified based on matching electrical ratings, mechanical form factors, and functional equivalence within the CC fuse classification.

Substiute Parts

ATQR3

Mersen USA Newburyport-MA L.L.C.In Stock: 679ATQR3 Datasheet

Current PartRFQ

FNQ-R-3

Eaton - Bussmann Electrical DivisionIn Stock: 1085FNQ-R-3 Datasheet

SimilarRFQ

KLDR003.HXP

Littelfuse Inc.In Stock: 805KLDR003.HXP Datasheet

SimilarRFQ

KLDR003.TXP

Littelfuse Inc.In Stock: 885KLDR003.TXP Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the ATQR3 are qualified based on the following electrical and mechanical parameters:

• Current Rating: 3A (exact match required)
• Voltage Rating - AC: 600 VAC (exact match required)
• Fuse Type: Cartridge (exact match required)
• Response Time: Slow Blow (exact match required)
• Class: CC (exact match required)
• Package / Case: 5AG, 10mm x 38mm (Midget) (exact match required)
• Mounting Type: Requires Holder (exact match required)

All three substitute parts meet these criteria. Additional parameters such as DC voltage rating, breaking capacity, and RoHS compliance status are provided for engineering evaluation but do not disqualify substitution based on AC-only applications.

Parameter Comparison

Engineering Selection Recommendations

All three substitute parts maintain active product status and carry CE, CSA, and UL certifications, meeting the same regulatory approval requirements. The FNQ-R-3 (Eaton - Bussmann Electrical Division, Limitron™ FNQ-R series) provides direct electrical and mechanical equivalence with 200kA breaking capacity at rated voltage. The KLDR003.HXP and KLDR003.TXP (Littelfuse Inc., POWR-GARD® KLDR series) offer identical AC ratings with additional 300 VDC capability and equivalent 200kA AC breaking capacity, providing extended functionality for mixed AC/DC applications.

Packaging considerations: FNQ-R-3 and KLDR003.HXP are supplied in bulk packaging, while KLDR003.TXP matches the original ATQR3 box packaging format. RoHS compliance differs between the original part (non-compliant) and all substitutes (ROHS3 compliant), which may be relevant for applications subject to RoHS directives.

Frequently Asked Questions (FAQ)

Q: Can FNQ-R-3, KLDR003.HXP, and KLDR003.TXP be used interchangeably with ATQR3?

A: Yes, all three parts are electrically and mechanically equivalent for AC applications at 3A, 600 VAC with CC class slow-blow characteristics and identical 5AG form factor. Physical dimensions and holder compatibility are identical.

Q: What is the difference between KLDR003.HXP and KLDR003.TXP?

A: Both parts are electrically identical with matching 3A, 600 VAC ratings and CC class specifications. The primary difference is packaging: KLDR003.HXP is supplied in bulk, while KLDR003.TXP is supplied in box packaging, matching the original ATQR3 format.

Q: Do the substitute parts support DC applications?

A: FNQ-R-3 is rated for AC only. KLDR003.HXP and KLDR003.TXP both support 300 VDC in addition to 600 VAC, providing extended capability for applications requiring DC protection.

Q: Are there RoHS compliance differences?

A: The original ATQR3 is RoHS non-compliant. All three substitute parts (FNQ-R-3, KLDR003.HXP, KLDR003.TXP) are ROHS3 compliant. This distinction is relevant for applications subject to RoHS directives.

Q: What certifications do the substitute parts carry?

A: All substitute parts carry CE, CSA, and UL certifications, matching the regulatory approval requirements for industrial and electrical applications.

Q: Are the substitute parts physically compatible with existing ATQR3 holders?

A: Yes. All substitute parts use the identical 5AG, 10mm x 38mm (Midget) form factor with 0.406" diameter and 1.500" length, ensuring mechanical compatibility with existing fuse holders designed for ATQR3.