ATQR1 Equivalent & Substitute Parts Reference

Part Overview

The ATQR1 is a CC class time-delay (slow blow) fuse rated for 600V AC at 1A, manufactured by Mersen USA Newburyport-MA L.L.C. This cartridge fuse is designed for circuit protection in electrical and industrial applications requiring coordinated overcurrent protection. The part is active in production with ROHS3 compliance and maintains 844 units in current inventory stock.

Substitute parts are identified based on matching electrical ratings (1A, 600V AC), mechanical compatibility (5AG cartridge format, 10mm x 38mm dimensions), and functional equivalence (CC class, slow blow response). Alternative sources ensure supply continuity and application flexibility across qualified manufacturers.

Substiute Parts

ATQR1

Mersen USA Newburyport-MA L.L.C.In Stock: 865ATQR1 Datasheet

Current PartRFQ

FNQ-R-1

Eaton - Bussmann Electrical DivisionIn Stock: 45450FNQ-R-1 Datasheet

SimilarRFQ

KLDR001.HXP

Littelfuse Inc.In Stock: 1111KLDR001.HXP Datasheet

SimilarRFQ

KLDR001.TXP

Littelfuse Inc.In Stock: 1434KLDR001.TXP Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility is determined by the following mandatory parameters:

• Current Rating: 1A (exact match required)
• Voltage Rating - AC: 600 VAC (exact match required)
• Fuse Type: Cartridge (exact match required)
• Class: CC (exact match required)
• Response Time: Slow Blow (exact match required)
• Package / Case: 5AG, 10mm x 38mm (exact match required)
• Product Status: Active (current production required)
• RoHS Status: ROHS3 Compliant (regulatory compliance required)

All three identified substitute parts meet these criteria. Variations in DC voltage rating, breaking capacity specifications, and MSL classification do not affect AC circuit protection equivalence for this application category.

Parameter Comparison

Engineering Selection Recommendations

All three substitute parts are functionally equivalent to the ATQR1 for AC circuit protection applications at 600V, 1A. Selection among these options is based on:

• Manufacturer availability and supply chain requirements
• Inventory levels: FNQ-R-1 (45,387 units), KLDR001.HXP (1,012 units), KLDR001.TXP (1,330 units)
• Regulatory compliance: All parts maintain CE, CSA, and UL certifications
• Active production status: All substitute parts are in current production

The FNQ-R-1 (Eaton - Bussmann Limitron™ FNQ-R series) offers the highest inventory availability. The KLDR001.HXP and KLDR001.TXP (Littelfuse POWR-GARD® KLDR series) provide dual voltage capability (600 VAC / 300 VDC) and are optimized for transformer protection applications, though this additional rating does not affect AC-only circuit equivalence.

Frequently Asked Questions (FAQ)

Q: Can KLDR001.HXP and KLDR001.TXP be used interchangeably with ATQR1?

A: Yes. Both Littelfuse parts meet all mandatory substitution criteria: 1A current rating, 600 VAC voltage rating, CC class, slow blow response, 5AG cartridge format, and 10mm x 38mm dimensions. The additional 300 VDC rating does not affect AC circuit protection performance.

Q: What is the difference between FNQ-R-1 and the Littelfuse alternatives?

A: All three parts are electrically and mechanically equivalent for 600V AC, 1A applications. The primary differences are manufacturer (Eaton vs. Littelfuse), series designation (Limitron™ FNQ-R vs. POWR-GARD® KLDR), and inventory availability. The Littelfuse parts include dual voltage capability (300 VDC), which is not required for AC-only circuits.

Q: Are these parts compatible with existing fuse holders?

A: Yes. All substitute parts use the 5AG cartridge format with 10mm x 38mm dimensions, which is the standard midget cartridge size. They are mechanically compatible with any holder designed for 5AG cartridges.

Q: Do all substitute parts have the same regulatory certifications?

A: Yes. ATQR1, FNQ-R-1, KLDR001.HXP, and KLDR001.TXP all carry CE, CSA, and UL approvals and maintain ROHS3 compliance.

Q: What is the breaking capacity difference between parts?

A: FNQ-R-1 and both Littelfuse parts specify 200kA breaking capacity at rated voltage. The ATQR1 breaking capacity is not specified in available documentation. This parameter does not affect substitution eligibility for standard circuit protection applications.