DC Load DC Control Solid State Relay - del30007

This is a DC Input DC Output SSR Solid State Relay. It was made for Printing or Photo Processing Equipment. It has an optical isolation and can be used for inductive loads. 



There was a big and small model i made - NO-NC SSR Plastic Box

The R1 Limits current and Z1 and D1 protects. The 2N3904 limits current in the Opto-Led. When the LED in CNY17-3  turns on, the Light passes thru a electrically insulating area and falls on the photo-transistor in the opto-coupler. This transistor conducts biasing Q2 PNP power transistor.  Then Q2 drives Q3 to saturation, turning it on. Q3 is a High-Voltage and High-Power rugged device. This can derive a solenoid, DC motor or Lamp.



I once got a mail about a smaller more advanced  relay - Sourcing the SP646 Solid State Relay

D2 is a freewheeling diode, inductive kickbacks are shorted by this. use a fast rec. Diode for better performance. Control Signal is - DC, 3-30V and Output Rating is - DC, 25V, 5A.

PNG-Schematic PCB - DT  L1  L2  SS  SM
 
DC Load DC Control Solid State Relay - del30007


Q3 BU508A is a High voltage fast-switching NPN power transistor.  Q2 2N6107 is a Power 7A 70V Discrete PNP.  2N3904 is a  NPN General Purpose Amplifier.



Better to overrate the devices while designing. If it for a continuous 10A use; use a 20A device and also recommend proper heat-sinks and ventilation or air circulation; especially when an array of SSR Devices are mounted within a control panel.   



This was the facia-sticker made out of  polycarbonate material. It was then reverse printed using screen printing. This facia was done  by a mechanical draughtsman. He  worked with an offset printing person to get the right fonts. The rest was hand-drawn. I gave the basic inputs and some color choices.

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