120 volt LED warning

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John From Detroit

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Apr 12, 2005
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Davison Michigan
In another forum a member posted that after just a few minutes on inverter power, He has an MSW inverter, his 120 volt LED night light was on fire.  Thankfully he was able to extinguish it before the RV was toast.. Just the Light assembly went by by.

Many of these devices use a method of voltage reduction that is frequency dependent, and when plugged into an MSW the frquency they "Sense" is 3 or more times what it should be (60hz) the result is they very quickly overheat due to over voltage and ....

Yet another thing to add to the "may not work on MSW" list:  LED night lights.

Old fashion incandescent... Should work perfectly.
 
That's what happens when you use a capacitor to do the job of a resistor.  The Kill-A-Watt has the same problem with MSW.
 
If the circuit is like this

Hot---/\/\/\/\/\/\/---&---Neutral (Where & is the led) then frequency don't much matter. but that resistor can generate a bunch of heat

Hot -----| |------/\/\/\/\---&---Neutral

The capacitor will have a "Reactance" (Which is like resistance) that varies with frequency. the higher the frequency the lower the reactance  And MSW's may look like 180 or 360 HZ instead of sixty to the Capacitor

For some reason, using a capicator to "Tap off" a 120 volt line for a low voltage circuit is a common practice.

NOTE: I use an LED light here to indicate presence of shore power (normallly) When I'm long time on the road or on limited power I switch that outlet to INVERTER... A true Sine type, and no problems.
 

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