skidave wrote:Thanks everyone.
I'm thinking of using the CL-90 in the circuit. I have used them before in some other builds.
Dave
Dave - sorry mate, you'll have to bear the brunt of my rant about CL90 and how guys just say "add a CL90" without really knowing what they are saying.
CL90 is one of the range of Inrush Current Limiters.
They work by having a large cold resistance (at turn on) and a low resistance when hot.
To get them up to the "hot" operating temperature is is important to choose the device based upon the expected operating current. It is NOT a one size fits all thing.
CL90 exhibits a resistance of 120 Ohms at 25 degrees C and is suitable for operating currents between 0.5 Amps RMS and a maximum of 2 Amps RMS.
See the data sheet for other Current Limiters suitable for other currents.
http://www.mouser.com/ds/2/168/920-325D-LR-245176.pdfFor Currents of less than 0.5 Amps or more than 2.0 Amps then CL90 is NOT suitable and you need to choose one of the other Current Limiters in the range.
For more limiting it is possible to use 2 or more Current Limiters in series BUT you MUST never use them in parallel (the one which heats first would just hog all the current and if the current is high enough would self destruct)
In the day job I used 3 in series in an Airborne Laser Power Supply to limit the peak current draw (at switch on) from the aircraft 28V DC supply. The regulatory authorities (FAA in the US and CASA here in Oz) get really "shitty" about popping aircraft fuses/circuit breakers and insist on a safe design. Having to fly in those same aircraft I'm not complaining about that.
I used then Rhopoint Components SG "Surge Guard" Series but they same.
http://www.rhopointcomponents.com/surge ... eries.htmlCheers,
Ian