Equivalent & Substitute Parts for Ohmite 850FR30

Part Overview

The Ohmite 850FR30 is a 300 mOhms ±1% 50W wirewound chassis mount resistor designed for high-power current sensing and load applications. This component features aluminum housing with flanged mounting and solder lug termination, suitable for operating temperatures from -55°C to 275°C.

The 850FR30 carries an obsolete product status. Identifying equivalent and substitute parts is necessary to maintain design continuity, ensure supply chain reliability, and support ongoing production or repair requirements for systems utilizing this component.

Key Parameters

Parameter	Value
Resistance	300 mOhms
Tolerance	±1%
Power Rating	50W
Composition	Wirewound
Temperature Coefficient	±90ppm/°C
Operating Temperature Range	-55°C to 275°C
Housing Type	Aluminum
Mounting Feature	Flanges
Lead Style	Solder Lugs
Package Type	Axial, Box

Substitute Part Grouping Explanation

Substitution for the 850FR30 is determined by strict equivalence across the following critical parameters:

Resistance value: 300 mOhms
Tolerance: ±1%
Power rating: 50W
Composition: Wirewound
Operating temperature range: -55°C to 275°C
Housing type: Aluminum
Mounting feature: Flanges
Lead style: Solder Lugs
Package configuration: Axial, Box

Two substitute parts meet these criteria:

850FR30E (Ohmite) — Parametric equivalent with identical electrical and mechanical specifications. Differs only in product status (Active vs. Obsolete) and RoHS compliance level.

UAL50-0R3F8 (Riedon) — Direct manufacturer alternative with equivalent core parameters. Physical dimensions show minor variations within acceptable tolerances. Includes additional features (current sense, flame proof, pulse withstanding, safety certifications).

Parameter Comparison

Parameter	850FR30 (Ohmite)	850FR30E (Ohmite)	UAL50-0R3F8 (Riedon)
Resistance	300 mOhms	300 mOhms	300 mOhms
Tolerance	±1%	±1%	±1%
Power Rating	50W	50W	50W
Composition	Wirewound	Wirewound	Wirewound
Temperature Coefficient	±90ppm/°C	±90ppm/°C	Not specified
Operating Temperature	-55°C to 275°C	-55°C to 275°C	-55°C to 275°C
Housing Type	Aluminum	Aluminum	Aluminum
Mounting Feature	Flanges	Flanges	Flanges
Lead Style	Solder Lugs	Solder Lugs	Solder Lugs
Package Type	Axial, Box	Axial, Box	Axial, Box
Length	1.938" (49.23mm)	1.938" (49.23mm)	1.969" (50.00mm)
Width	1.156" (29.36mm)	1.156" (29.36mm)	1.142" (29.00mm)
Height (Seated Max)	0.620" (15.75mm)	0.620" (15.75mm)	0.630" (16.00mm)
Product Status	Obsolete	Active	Active
RoHS Status	Non-compliant	ROHS3 Compliant	ROHS3 Compliant

Engineering Selection Recommendations

850FR30E (Ohmite) is the primary substitute for the obsolete 850FR30. This part maintains identical electrical and mechanical specifications while offering Active product status and ROHS3 compliance. Selection of 850FR30E eliminates obsolescence risk and aligns with current regulatory requirements without requiring design modification.

UAL50-0R3F8 (Riedon) serves as a secondary alternative when 850FR30E availability is constrained. This part meets all core electrical parameters and operating temperature requirements. Physical dimensions vary within 0.031" (0.77mm) on length and 0.014" (0.36mm) on height, which may require mechanical verification in space-constrained applications. The UAL50-0R3F8 includes additional safety and performance features (flame proof, pulse withstanding, current sense capability) and carries ROHS3 compliance with MSL 1 rating.

Both substitutes are electrically and mechanically compatible with the original 850FR30 design. Selection between them depends on availability, compliance requirements, and mechanical fit constraints specific to the application.

Frequently Asked Questions (FAQ)

Q: Can 850FR30E directly replace 850FR30 without design changes?

A: Yes. The 850FR30E maintains identical electrical specifications (300 mOhms ±1%, 50W, ±90ppm/°C) and mechanical dimensions (1.938" L × 1.156" W × 0.620" H). No circuit or layout modifications are required.

Q: What is the primary difference between 850FR30 and 850FR30E?

A: Product status and compliance. The 850FR30E is Active and ROHS3 compliant, while the 850FR30 is Obsolete and RoHS non-compliant. Electrical and mechanical performance are identical.

Q: Can UAL50-0R3F8 be used in place of 850FR30?

A: Yes, with mechanical verification. The UAL50-0R3F8 meets all electrical requirements and operating temperature range. Physical dimensions differ slightly: length is 0.031" longer (1.969" vs. 1.938"), width is 0.014" narrower (1.142" vs. 1.156"), and height is 0.010" taller (0.630" vs. 0.620"). Confirm these variations do not conflict with PCB layout or enclosure constraints.

Q: Are there packaging differences between these substitutes?

A: The 850FR30 is listed as obsolete with unspecified packaging. Both 850FR30E and UAL50-0R3F8 are supplied in Bulk packaging. Confirm bulk quantities meet procurement requirements.

Q: Which substitute offers the best compliance profile?

A: Both 850FR30E and UAL50-0R3F8 are ROHS3 compliant and REACH unaffected. The UAL50-0R3F8 includes additional safety certifications (flame proof, pulse withstanding) and carries MSL 1 (Unlimited) rating, suitable for extended storage without moisture sensitivity concerns.

Q: Is temperature coefficient specified for all substitutes?

A: The 850FR30 and 850FR30E specify ±90ppm/°C. The UAL50-0R3F8 temperature coefficient is not provided in available documentation. If temperature coefficient is critical to application performance, verify this parameter with the manufacturer before selection.

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