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    Solid state relay, 3 phase, SSR-40DA, 40A 3-32V DC to AC

    5 out of 5 based on 2 reviews | Write a review
    Low price 40 amp solid state relay, 3 phase SSR-40DA, DC control AC, input voltage 3-32V DC, load voltage 24-480V AC, zero cross switch type, LED working indicator, panel mount, best SSR for heavy industries.
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    Delivery date: 6-12 days


    40A 3-phase 3-32V DC to AC solid state relay (SSR-40DA) features high structural strength, good impact resistance, and strong shock resistance. The SSR relay offers a reliable switching the commercial and industrial loads, such as computer peripheral interface device, printing machine, molding machine, food machine, packaging machine, and so on.

    • Built in RC absorption
    • Photoelectric isolation
    • SCR output
    • LED indicator for operation status
    • Removable protective cover for safety
    • Panel mount
    • Zero-crossing switch type


    Model ATO-SSR-TH40DA
    Input Control voltage range 3-32V DC
    Max. input current 20mA
    Must operate voltage 4V DC
    Must release voltage 2.7V DC
    Output Load voltage range 24-480V AC
    Peak voltage 800V AC
    Maximum load current 40A
    Maximum off-state leakage current 8mA
    Maximum off-state time 10mS
    Maximum on-state voltage drop 1.5V
    General Type DC to AC, 3 phase
    Dimension L – W – H (mm) 105х74.8х33
    Weight 500g
    Dielectric strength (input to output) 4000V
    Dielectric strength (input, output to the base) 2500V
    Operating temperature -20℃~ 80℃
    Mount Panel
    Certification CE


    1. When the load is a resistive load, the maximum load current of the selected SSR should be 2~3 times greater than the actual load current;
    2. When the load is an inductive load, the maximum load current of the selected SSR should be more than 7~8 times the actual load current.
    3. When the maximum load current is higher than 10A, a heat sink must be installed to the solid state relay, or the SSR relay should be mounted on a metal base plate with heat dissipation effect, and the thermal grease is applied between them.

    Dimensions (Unit: mm)

    3-phase SSR Relay Dimensions

    Wiring Diagram

    3-phase 3-32V DC to AC SSR Wiring Diagram

    Tips: Thermal design and radiator selection of solid state relay

    There is certain internal power dissipation in solid state relays’ operation. The dissipation value is mainly determined by product of output voltage drop and load current, embodied in the form of heat radiation. The quality of heat dissipation directly affects maximum load current of solid state relays and maximum allowable temperature of the working environment and it is one of the important factors that affect the reliable operation of SSRs. Therefore, we should pay attention to thermal design and radiator selection so that SSRs may work reliably and failure of and damages caused by poor heat dissipation to solid state relays can be avoided.

    In general, solid state relays, whose output current is less than 5A, use natural convection air enough to achieve the purpose of cooling, but when installed, solid state relays need a good convection environment and the space between each solid state relay should not be less than the width of a SSR. It is essential for those solid state relays with a load current greater than 10 A to use suitable radiators, even forced air cooling (air speed at 6 m/s) or water-cooling if necessary. The good heat dissipation condition is very important for SSRs’ reliable work.

    Existing reviews of Solid state relay, 3 phase, SSR-40DA, 40A 3-32V DC to AC
    Can you provide heat sink with your solid state relay?
    Can you provide heat sink with your solid state relay?
    From: Madalin | Date: 21/09/2020
    Was this review helpful? Yes No (0/0)
    ATO Responded
    Yes, we can but the price is extra.
    So far the SSR works great and no problems.
    I use this unit to switch a water pump on/off. The solid state relay indeed got hot while running without a heat sink. Then added a heat sink to make it running longer and safer. So far works great and no problems.
    From: Gabriel | Date: 03/01/2019
    Was this review helpful? Yes No (0/0)
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