After some advice here I'm wondering if this is the correct design of my circuit.
I'm now using a SSR as the control device to the contactor. The diode, I believe, should not only protect the SSR from back EMF, but also the capacitor as well. I know I will also need a resistor or thermistor prior to the capacitor so the capacitor itself does not cause a large inrush current, both when the system is turned on, and again after the switch is opened again.
The value of that resistor is something I'm still somewhat unsure of how to calculate.
For application details, the system will be on for at minimum 2 minutes before the relay is closed to engage the contactor. The contactor will then be on for up to 60 seconds before being disengaged. The capacitor needs to be able to recharge within 60 seconds to be able to close the contactor again if necessary.
If I'm understanding correctly, upon startup, the resistor/thermistor will suppress the capacitor inrush and slowly charge it (charge time depending on resistance value). As soon as my switch is closed, the capacitor will provide the full energy required to close the contactor coil. From that point on, the 24V source will provide enough energy to hold the contactor in, while also slowly charging the capacitor.
Once the switch is re-opened, the diode with suppress the back EMF, while the capacitor recharges.
Does this design seem reasonable? If so, how do I determine the value of the resistor to complete the design?
http://www.kvc.com.my/EnterpriseChannel/SharedResources/Datasheet/0/?ProductId=1000066755&Filename=SCHNEIDER-LX4-FH024.pdf http://www.mouser.com/ds/2/293/e-nt-15067.pdf https://www.us.tdk-lambda.com/ftp/Specs/dpp120-240.pdf