Recently I visited a site where I saw that in an inverter AC fuse are use for DC. It is quite odd for me! Is it ok to use the same?
What are the factors to be considered when we use AC fuse in DC and DC fuse in AC?
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2\$\begingroup\$ They are generally interchangeable. However the rating (voltage and current) will not match. A 600VAC fuse will likely have an equivalent DC rating of closer to 300V. A fuse that has a dc rating on the package may have an AC rating given in the datasheet. \$\endgroup\$– crasicDec 8, 2015 at 4:44
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3 Answers
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I would be worried if it's the other way around because the DC arc is not self-extinguishing like the AC one is at the zero crossing. Trying to be cheap with fuses at one point I realized that even a 0.3A AC fuse can glow for a couple of seconds on DC... And this was 250V AC rated fuse and I was only using at 12V DC.
For an inverter, if the electronics fail short to the DC rail somehow and it "decides" to output DC... I'd be glad the fuse was DC-rated (as long as it's not under-rated in terms of AC voltage).
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\$\begingroup\$ Yes. A DC-rated fuse can work with AC or DC, but an AC-rated fuse might not quench a DC arc. \$\endgroup\$– bitsmackDec 8, 2015 at 5:30
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It depends. In most cases a -same size- DC fuse will work in an AC circuit. UNLESS it's on something with an electric motor circuit. Motors have a 'start' amp load and a 'run' amp load. A DC fuse is unforgiving of spikes and will quickly burn out when the motor starts -unless- it is rated at several times higher than the 'run' amps of the motor
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1\$\begingroup\$ Generally yes but there are a lot of characteristics to take into account including the voltage. The element must fail open if a fault occurs. \$\endgroup\$– GilJul 24, 2021 at 21:45
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The DC fuses generally are in a smaller package because of the lower voltages involved. The major concern is will the link melt and open the circuit when a fault occurs. If the voltage is high enough for a given fuse it will ARC and continue conducting. Many of the higher voltage fuses have a material in them that when the link melts it quenches the ARC. It can be as simple as a power that fills the hole left by the melted fuse element. The typical fuse for motor protection will withstand an overload for about 8 to 12 seconds depending on the actual load and the designer's intent. There are several ways of sizing them, I will not go into that here. There are also several ways of constructing fuses, some even have dual elements. There are also fuses called fast blow, many times used in electronic circuits. Try this link for more details. https://www.electricaltechnology.org/2014/11/fuse-types-of-fuses.html In the end you will find thousands of different fuses each designed for a specific purpose.
