First a notice of warning - I am not very knowledgeable in electronics, so go easy.
I am attempting to use a thermistor to limit the inrush current to 2 Meanwell switching power supplies in parallel (models HLG-240-24A and HLG-120H-12A, specifically). I am powering these from a regular 20A 120VAC circuit. According to the spec sheets I can expect over 100A inrush, so I need some sort of limiting. I attempted to use what I thought was the correctly-sized thermistor, but I only let the magic smoke out.
I used a 10Ω thermistor (120V/20A=8.5Ω) rated to 8A (power supplies total 5.4A steady state input) and able to accommodate roughly 90J/6000uF on the input side (Meanwell said there is only 150uF on the 24V model and 82uF on the 12V one. 170Vpeak & 232uF in the J=½CV² equation = 3.4J). What am I missing?
I am attempting to use a thermistor to limit the inrush current to 2 Meanwell switching power supplies in parallel (models HLG-240-24A and HLG-120H-12A, specifically). I am powering these from a regular 20A 120VAC circuit. According to the spec sheets I can expect over 100A inrush, so I need some sort of limiting. I attempted to use what I thought was the correctly-sized thermistor, but I only let the magic smoke out.
I used a 10Ω thermistor (120V/20A=8.5Ω) rated to 8A (power supplies total 5.4A steady state input) and able to accommodate roughly 90J/6000uF on the input side (Meanwell said there is only 150uF on the 24V model and 82uF on the 12V one. 170Vpeak & 232uF in the J=½CV² equation = 3.4J). What am I missing?