I have a requirement where I need to control around 20 solenoids which is housed separate from a Raspberry pi, ATX PSU and veroboard containing my logic circuit. For convenience I will call them CASE-A and CASE-B.
The solenoid requires 0.5A@12VDC and the pump requires 3A@12VDC. This will require me to transfer about 13A between CASE-A & CASE-B. I need the connections to be modular so that I can pull the cases apart for troubleshooting/maintenance.
Can I use the standard ATX 24-pin connector ? (something like this–http://www.amazon.com/29-5cm-Computer-Female-Extension-Power/dp/B00EZ50W36/)
I can see the following way to connect them up,
(a) In CASE-A, connect one leg of each solenoid and the postitive lead of the pump to one wire of the ATX 24-pin cable. In CASE-B, connect the other end pin to the +12V lead in the ATX PSU.
(b) In CASE-A, run a separate wire from the other leg of each solenoid and the negative lead of the pump to separate wires of ATX 24-pin cable(21 wires). In CASE-B, connect the other end pins to my veroboard logic circuit (the circuit would then complete the connection to ground depending upon logic controlled by the RPI).
Will the standard ATX 24-pin connector be able to handle the load?
Is there a different way?
Thanks
Vijay
PS: Veroboard logic will be similar to Will this schematic work?, however instead of 5 pumps there will be one pump and 20 solenoids.
Best Answer
The datasheet (it's a great thing to find such details) of the connector tells us:
The advice of Molex in their additional product specification actually shows, that on a fully populated 24 pin Wire-To-Board connector, the rated current is decreased to 8A per pin:
I wouldn't go anywhere near the maximum on a single pin though, at that current they will get hot (specified to a temperature rise of 30K above ambient at rated current).
So if you spread out the load over several of the 24 pins, you should be fine.
A low quality connector might not hold up to those specs - another reason why not to go to the limits.