------Question for SL221R020 Please Put your question below------ I have led light circuits that range in current from 8 amps to 14 amps. The rcbos trip due to inrust current. Can I place this SL221R020 in series with the load ? Generally the room temp is about 18 to 25 degrees . Will this prevent the inrush ?
Hello darren3,
Welcome to the DigiKey TechForum.
I don’t believe this will solve your problem. This is designed to protect a circuit from high inrush current, like a large peak on the incoming line. This can handle up to 20 amps of current, so I don’t think it will prevent an inrush from the LED on the output.
I’m not an engineer, but maybe one of the engineers that monitor the TechForum can add their knowledge to this post.
I thought it was designed for high capacitive circuits to with stand initial inrush. If an engineer could respond that would be appreciated.
The device in question offers a 1 ohm resistance at room temperature; while its use could potentially reduce inrush somewhat, the peak values are still in the hundreds of amps depending on one’s line voltage.
One should also be aware that such devices get quite hot as a necessary and normal part of their operation; the datasheet indicates that temperatures as high as 187°C at maximum rated current can be expected. Accommodating this in an installation is not convenient.
It should be appreciated that the thermally-operated character of these devices has drawbacks; cycling between room temperature and Hot in a short period of time is mechanically stressful, and promotes failure. The devices also need sufficient time to cool off in order to perform their function. If inrush is indeed the issue at hand here, and if the devices actually address the issue under normal conditions, it’s very likely that they’d fail to do so when faced with glitches/brief interruptions of the utility service of that sort that are just long enough that one has to reset the clocks on small appliances.
This said, assuming the referenced RCBO is of a sort intended to provide both ground fault and over-current protection, it’s unclear which function is causing the nuisance tripping. An NTC inrush limiter could potentially address both, though for the reasons mentioned its not a solution one should reach for without serious thought.