Equivalent & Substitute Parts for Cornell Dubilier Electronics 21FD3710

Part Overview

The Cornell Dubilier Electronics 21FD3710 is a 10 µF film capacitor rated for 370V AC operation with polypropylene metallized dielectric construction. This component is designed for motor run and power factor correction applications in chassis-mounted configurations. The part is classified as obsolete, necessitating identification of active equivalent alternatives that maintain electrical and mechanical compatibility for continued system operation and maintenance.

Key Parameters

Parameter	Value
Capacitance	10 µF
Tolerance	±10%
Voltage Rating - AC	370V
Dielectric Material	Polypropylene (PP), Metallized
Operating Temperature Range	-40°C ~ 70°C
Mounting Type	Chassis Mount, Requires Holder/Bracket
Package / Case	Radial, Can
Termination	Quick Connect, Disconnect
Lead Spacing	0.813" (20.64mm)
Applications	Motor Run; Power Factor Correction (PFC)

Substitute Part Grouping Explanation

Substitution of the 21FD3710 is determined by strict equivalence across the following critical parameters:

Electrical Parameters:

Capacitance: 10 µF (exact match required)
Tolerance: ±10% (exact match required)
Voltage Rating - AC: 370V minimum (equal or higher voltage rating acceptable)
Dielectric Material: Polypropylene (PP), Metallized (exact match required)
Operating Temperature Range: -40°C ~ 70°C (exact match required)

Mechanical Parameters:

Package / Case: Radial, Can (exact match required)
Mounting Type: Chassis Mount, Requires Holder/Bracket (exact match required)
Termination: Quick Connect, Disconnect (exact match required)
Lead Spacing: 0.813" (20.64mm) nominal (within manufacturing tolerance)
Physical Dimensions: Compatible with original mounting envelope

Application Parameters:

Motor Run applications
Power Factor Correction (PFC) applications

Substitute parts are grouped into two categories: direct equivalents maintaining 370V AC rating, and higher-voltage alternatives rated for 440V AC that provide electrical margin while maintaining all other specifications.

Parameter Comparison

Parameter	21FD3710	21FD3710A-F	SFP37S10K238B	SFP37T10K238B-F	SFP44T10K238B-F
Capacitance	10 µF	10 µF	10 µF	10 µF	10 µF
Tolerance	±10%	±10%	±10%	±10%	±10%
Voltage Rating - AC	370V	370V	370V	370V	440V
Dielectric Material	Polypropylene (PP), Metallized	Polypropylene (PP), Metallized	Polypropylene (PP), Metallized	Polypropylene (PP), Metallized	Polypropylene (PP), Metallized
Operating Temperature	-40°C ~ 70°C	-40°C ~ 70°C	-40°C ~ 70°C	-40°C ~ 70°C	-40°C ~ 70°C
Mounting Type	Chassis Mount, Requires Holder/Bracket	Chassis Mount, Requires Holder/Bracket	Chassis Mount, Requires Holder/Bracket	Chassis Mount, Requires Holder/Bracket	Chassis Mount, Requires Holder/Bracket
Package / Case	Radial, Can	Radial, Can	Radial, Can	Radial, Can	Radial, Can
Termination	Quick Connect, Disconnect	Quick Connect, Disconnect	Quick Connect, Disconnect	Quick Connect, Disconnect	Quick Connect, Disconnect
Lead Spacing	0.813" (20.64mm)	0.813" (20.64mm)	0.810" (20.57mm)	0.810" (20.57mm)	0.810" (20.57mm)
Product Status	Obsolete	Active	Active	Active	Active
RoHS Status	RoHS non-compliant	ROHS3 Compliant	RoHS non-compliant	ROHS3 Compliant	ROHS3 Compliant

Engineering Selection Recommendations

Primary Substitute: 21FD3710A-F

The 21FD3710A-F is the direct active equivalent of the obsolete 21FD3710. This part maintains identical electrical specifications (10 µF, ±10%, 370V AC) and mechanical configuration (Radial, Can, Quick Connect termination). The 21FD3710A-F is classified as Active product status with ROHS3 compliance, providing regulatory alignment for new designs and system updates. Height dimension is reduced from 2.880" to 2.630", which remains compatible with standard chassis-mount holder configurations. This part is the preferred replacement for direct substitution.

Secondary Substitutes: SFP37T10K238B-F and SFP37S10K238B

Both SFP37 series parts maintain the 370V AC rating and all electrical parameters identical to the original 21FD3710. These parts belong to the SF series and feature slightly reduced physical dimensions (1.870" diameter, 2.500" height) compared to the original. The SFP37T10K238B-F carries ROHS3 compliance and Active status. The SFP37S10K238B is Active but RoHS non-compliant. Lead spacing is 0.810" (20.57mm), within manufacturing tolerance of the original 0.813" specification. These parts are suitable for applications where space constraints or holder compatibility permits the dimensional variation.

Higher-Voltage Alternative: SFP44T10K238B-F

The SFP44T10K238B-F provides 440V AC rating while maintaining 10 µF capacitance and all other electrical and mechanical specifications. This part is suitable for applications where the system voltage may exceed 370V or where additional voltage margin is required. ROHS3 compliance and Active status are confirmed. Physical dimensions and termination are identical to the SFP37T10K238B-F series. Selection of this part requires verification that the 440V rating does not introduce unintended electrical characteristics in the application circuit.

Frequently Asked Questions (FAQ)

Q: Can the 21FD3710A-F be used as a direct replacement for the obsolete 21FD3710?

A: Yes. The 21FD3710A-F maintains identical electrical specifications (10 µF, ±10%, 370V AC, polypropylene metallized dielectric) and mechanical configuration (Radial, Can, Quick Connect termination, 0.813" lead spacing). The reduced height dimension (2.630" versus 2.880") is compatible with standard chassis-mount holder brackets. This is the recommended primary substitute.

Q: What is the difference between the SFP37 and SFP44 series substitutes?

A: The SFP37 series maintains the original 370V AC rating. The SFP44 series provides a higher 440V AC rating. Both maintain 10 µF capacitance and identical operating temperature range. Selection between these series depends on the system voltage requirement. The 440V rating of the SFP44T10K238B-F provides additional voltage margin but must be verified as compatible with the application circuit design.

Q: Are there any dimensional compatibility concerns with the SFP37 series substitutes?

A: The SFP37 series parts feature slightly reduced physical dimensions (1.870" diameter, 2.500" height) compared to the original 21FD3710 (1.875" diameter, 2.880" height). Lead spacing is 0.810" (20.57mm) versus the original 0.813" (20.64mm), a difference within manufacturing tolerance. These dimensional variations are compatible with standard chassis-mount holder configurations. Verify holder bracket compatibility in the specific application.

Q: What is the significance of RoHS compliance status in selecting a substitute?

A: RoHS compliance status indicates regulatory alignment with environmental and hazardous substance restrictions. The 21FD3710A-F, SFP37T10K238B-F, and SFP44T10K238B-F carry ROHS3 compliance, suitable for applications subject to regulatory requirements. The SFP37S10K238B is RoHS non-compliant. Selection should align with the regulatory requirements of the target application and market.

Q: Can the SFP44T10K238B-F (440V) be used in a 370V application?

A: The SFP44T10K238B-F is rated for 440V AC operation and maintains all other electrical specifications identical to the 370V-rated alternatives. Use in a 370V application is electrically permissible, as the component is rated for higher voltage. However, the application circuit design must be verified to confirm that the 440V rating does not introduce unintended electrical characteristics or performance changes.

Q: What packaging options are available for these substitutes?

A: The 21FD3710A-F, SFP37T10K238B-F, and SFP44T10K238B-F are supplied in Bulk packaging. The SFP37S10K238B packaging specification is not designated. Bulk packaging is standard for component procurement in production and maintenance environments.

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