Thread: inrush surge
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Jeff Liebermann Jeff Liebermann is offline
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Default inrush surge

On Thu, 21 Nov 2013 06:35:37 -0800, "William Sommerwerck"
wrote:

Thoughts? (Including "You're an idiot!" Well, there were no stories about the
owner's house burning down.)


Burning the house down is a bit extreme, but such burnt offerings have
been known to appease the Gods of Electronics.

When all else fails, a measurement or three might be a good idea. Put
a small value resistor (0.1 ohm) in series with the AC line, and
measure the inrush current and duration. Then compare with the fuse
ratings and see if the selected fuse type and value are sane.

I've run into cute tricks like a big Lambda 12V power supply, that had
a 10 ohm resistor in series with the AC power lead. When the power
supply output finally stabilized, a relay would short out the 10 ohm
resistor so that full power could be delivered. That works great
until the relay contacts arced closed, causing the PS to suck full
current on startup and blowing the fuse. It took a while to find that
one.

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Jeff Liebermann
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