[Lifetime Warranty] SSR-40DA DC to AC Solid State Relay | Pack of 3
Set of three SSR-40DA solid state relay modules with 3-32VDC input and 24-380VAC output.
Wiring diagram for SSR-40DA solid state relay showing DC input and AC load connections.
Single SSR-40DA solid state relay module with copper output terminals and heat-dissipating metal back plate.
Two SSR-40DA solid state relay modules showing front label and metal base plate details.
Collage showing wide industrial and residential applications for SSR-40DA solid state relay modules.
SSR-40DA solid state relay module showing easy installation in an industrial control panel circuit.
Couple relaxing on a sofa using a remote control to operate a wall-mounted Blue Star air conditioner.
Set of three SSR-40DA solid state relay modules with 3-32VDC input and 24-380VAC output.
Wiring diagram for SSR-40DA solid state relay showing DC input and AC load connections.
Single SSR-40DA solid state relay module with copper output terminals and heat-dissipating metal back plate.
Two SSR-40DA solid state relay modules showing front label and metal base plate details.
Collage showing wide industrial and residential applications for SSR-40DA solid state relay modules.
SSR-40DA solid state relay module showing easy installation in an industrial control panel circuit.
Couple relaxing on a sofa using a remote control to operate a wall-mounted Blue Star air conditioner.
Lifetime Warranty

[Lifetime Warranty] SSR-40DA DC to AC Solid State Relay | Pack of 3

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SSR-40DA Solid State Relay

Key Features

  • Model: SSR-40DA
  • Type: Single-phase solid state relay
  • Control Input Voltage: 3-32V DC
  • Load Output Voltage: 24-380V AC
  • Maximum Load Current: 40A
  • Switching Method: Electronic, for fast response and long service life
  • Construction: Aluminum heat-dissipating base plate with screw terminals

Replaces / Cross-Reference Part Numbers

  • SSR-40DA
  • Replaces solid state relays with matching electrical specifications (3-32V DC control, 24-380V AC load, up to 40A)

Compatibility & Fitment

  • Suitable for various AC load switching applications including PID temperature controllers, industrial automation, HVAC systems, and motor controls.
  • Compatible with microcontrollers and PLCs that provide a 3-32V DC output signal.
  • A heat sink is required for loads exceeding 10A to prevent thermal damage and ensure rated performance.

When to Replace

  • Relay fails to activate the load when a control signal is present.
  • Relay remains stuck in the "ON" position, keeping the load powered without a control signal.
  • Unit overheats under normal operating conditions (with an appropriate heat sink).
  • Visible damage, such as a cracked housing or corroded terminals.

Installation Tips

  • Disconnect all power sources before installation or servicing.
  • Mount the relay on a correctly sized heat sink, especially when switching loads greater than 10A.
  • Apply a thin layer of thermal paste between the relay's metal base and the heat sink for optimal heat transfer.
  • Connect control (input) and load (output) wiring to the correct terminals as marked on the device.
  • Ensure all wire connections are secure to prevent arcing and overheating.
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  • Perfect fit

    Perfect fit

    Diverse applications in controlling computer peripherals, AC motors, lighting systems, spanning automation setups to enhance security and performance
  • Premium quality

    Premium quality

    This product adopts a heat-dissipating metal back plate and a copper terminal lug for superior conductivity.
  • Saving solution

    Saving solution

    Enjoy the great feeling when your engine is repaired and works properly like before - BlueStars brings DIY solutions to help you deal with any trouble
  • Simple installation

    Simple installation

    Solid State Relay is a simple part & just takes few minutes to install and will save you at least a hundred bucks in labor.
BRINGING RELIABILITY TO THE SWITCH

BRINGING RELIABILITY TO THE SWITCH

Brand Model Number
Model SSR-40DA
Control method DC to AC
Control (Input) Voltage 3-32VDC
Load (Output) Voltage 24-380VAC
Min Control Current 3MA
Max Control Current 35MA
Current & Frequency 40A

FAQ

SSR-40DA is a single-phase solid state relay with a DC control input and an AC load output. For this part, the control side is 3-32V DC, and the switched load side is 24-380V AC. The relay is commonly identified by part number SSR-40DA.
This type of relay is typically used where a low-voltage DC signal needs to switch an AC load, such as temperature controllers, PID controllers, heaters, ovens, small automation systems, and other single-phase AC equipment. It should only be used where the control signal is DC and the load being switched is within the relay's AC voltage and current range.
Common failure symptoms include the load not turning on when a DC control signal is present, the load staying on continuously even when the control signal is removed, erratic switching, or overheating at the relay body or terminals. In temperature-control applications, a failed relay may cause a heater to never energize or to remain energized without cycling properly.
Confirm the existing relay is an SSR-40DA or matches the same function: DC input 3-32V and AC output 24-380V in a single-phase configuration. Also verify your controller actually sends a DC trigger signal, check the load current draw, inspect terminal wiring for heat damage or looseness, and make sure the mounting surface or heat sink is still in good condition.
In many applications, yes. Solid state relays generate heat under load, especially as current increases. Higher-current loads or long duty cycles typically require mounting to a suitable metal surface or heat sink with proper thermal transfer. If the previous relay failed from overheating, review current draw, enclosure ventilation, terminal tightness, and heat sinking before installing the replacement.
Installation is usually straightforward for someone familiar with electrical wiring. Typical tools include a screwdriver for the terminal screws, a meter for verifying the control signal and load voltage, and possibly ring or fork terminals depending on your wiring setup. Always disconnect power before servicing. In a simple panel swap, replacement often takes about 10 to 20 minutes.
Yes. The low-voltage DC control terminals and the high-voltage AC load terminals must be connected correctly and kept separate. This relay is for DC-to-AC switching only, not AC-to-AC or DC-to-DC use. Because it is a semiconductor relay with no moving contacts, proper polarity on the DC input and secure terminal connections are important for reliable operation.