HD4840 Solid State Relay - Equivalent & Substitute Parts

Part Overview

The HD4840 is a Solid State Relay (SSR) manufactured by Sensata-Crydom, configured as a SPST-NO (Single Pole Single Throw - Normally Open) relay in a hockey puck form factor. This component is designed for AC load switching applications with zero-cross detection, operating from 3–32VDC input control voltage and supporting loads from 48V to 530V at 40A maximum current. The part is RoHS Compliant and maintains Active product status. Equivalent and substitute parts are identified to support procurement flexibility, inventory management, and supply chain continuity for applications requiring compatible SPST-NO solid state relay functionality.

Substiute Parts

HD4840

Sensata-CrydomIn Stock: 1019HD4840 Datasheet

Current PartRFQ

84137120N

CrouzetIn Stock: 84984137120N Datasheet

MFR RecommendedRFQ

ASR-SI480D40ZW-L

Altran Magnetics, LLCIn Stock: 1060ASR-SI480D40ZW-L Datasheet

MFR RecommendedRFQ

SSR-480D50

TE Connectivity Potter & Brumfield RelaysIn Stock: 1020SSR-480D50 Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the HD4840 are qualified based on the following critical parameters that determine functional compatibility:

• Circuit Configuration: All substitutes must be SPST-NO (1 Form A) to maintain identical switching topology
• Output Type: AC with Zero Cross detection is required for synchronized load switching
• Mounting Type: Chassis Mount configuration ensures mechanical compatibility
• Package / Case: Hockey Puck form factor is mandatory for physical fit
• Termination Style: Screw Terminal connection is required for electrical interface compatibility
• Input Voltage Range: Must support the control voltage range of 3–32VDC or a compatible subset
• Load Voltage Range: Must support the application load voltage window of 48–530V or higher
• Load Current: Must support minimum 40A switching capacity

The three identified substitutes meet these core criteria while offering variations in load current capacity (40A or 50A) and maximum load voltage (530V or 660V). All substitutes maintain SPST-NO topology, AC zero-cross output, chassis mount configuration, hockey puck packaging, and screw terminal termination.

Parameter Comparison

Engineering Selection Recommendations

All three substitute parts maintain Active product status and RoHS compliance, ensuring regulatory and supply chain viability.

ASR-SI480D40ZW-L (Altran Magnetics, LLC) provides the closest electrical match to the HD4840, with identical 40A load current and 48–530V load voltage range. This part is ROHS3 Compliant and REACH Unaffected, making it suitable for applications with strict environmental compliance requirements.

84137120N (Crouzet) and SSR-480D50 (TE Connectivity Potter & Brumfield Relays) both offer increased load current capacity (50A) and extended maximum load voltage (660V), providing design margin for applications requiring higher switching capacity. The 84137120N is RoHS Compliant with MSL 1 (Unlimited), while the SSR-480D50 is ROHS3 Compliant with REACH Affected status.

Selection between these substitutes depends on application load current requirements, maximum load voltage specification, and environmental compliance mandates. All three parts are electrically and mechanically compatible with the HD4840 within their specified parameter ranges.

Frequently Asked Questions (FAQ)

Q: Can the HD4840 be directly replaced with any of these substitute parts?

A: Yes, all three substitute parts are functionally compatible with the HD4840 for SPST-NO AC relay applications. They share identical circuit configuration, output type, mounting type, package form factor, and termination style. Compatibility is confirmed when the application load voltage and current requirements fall within the specified ranges of the substitute part.

Q: What is the difference between the 40A and 50A versions?

A: The HD4840 and ASR-SI480D40ZW-L are rated for 40A maximum load current, while the 84137120N and SSR-480D50 are rated for 50A. The 50A versions provide additional switching capacity and are suitable for higher-current applications. Selection should be based on actual application load current requirements.

Q: Are there input voltage differences I should consider?

A: The HD4840 accepts input control voltage from 3–32VDC, while all three substitutes accept 4–32VDC. Applications using control voltages below 4VDC require the HD4840 or equivalent parts with 3VDC minimum input specification.

Q: What is the significance of the maximum load voltage range?

A: The HD4840 supports load voltages up to 530V, while the 84137120N and SSR-480D50 support up to 660V. Applications operating at load voltages above 530V require one of the higher-rated substitutes. Applications within the 48–530V range are compatible with all parts.

Q: Do these parts have different RoHS compliance levels?

A: The HD4840 is RoHS Compliant. The ASR-SI480D40ZW-L and SSR-480D50 are ROHS3 Compliant, representing a more recent compliance standard. Both compliance levels are acceptable for most applications; selection depends on specific procurement or environmental requirements.

Q: Are there packaging differences between these parts?

A: The HD4840 and SSR-480D50 are supplied in Bulk packaging, while the 84137120N and ASR-SI480D40ZW-L are supplied in Box packaging. Packaging does not affect electrical or mechanical compatibility; it reflects supplier inventory and distribution practices.