Yes Kalpak. You are very correct in that DC coils, unlike AC coils do not have this problem of high inrush. In fact the solenoid supplier only quotes a fixed wattage for all conditions unlike AC coils which have a separate and hogher current quoted as inrush.

But as Andy had pointed out, DC coils do have this different pull in voltage and holding voltage. The latter is quite low - like about 18V for a 24V pull in and we use this property to conserve power when holding coils ON for long.

Some suggestions and my observations :

- Add a capacitor to handle the dip. I need huuuge ones and not practical at this stage.
- round robin switching. A good option. But I will need a timer with four outputs - again not a problem if it was mine but what I have shown is actually a OMRON timer model H5CX used in twin timer mode.

I will try out the following :

1. Try to increase the cross section of the connecting cables to double the size - from 0.75 to 1.5 sq mm
2. Bring in another power supply for the second SSR.
3. Use a scope to check the profile now and after the change.

Thanks to all who helped for opening up new ideas to check out when everything was looking OK but not working OK !

Raghu