I have a variac transformer rated at 7.5 amps but the fuse burned out. I want to increase the rating to 20 amps, can I do this by replacing the fuse with a 20 amp fuse?
No. changing the fuse doesn't change the rating. if the fuse burned out it means you are overloading the variac. if you put in a bigger fuse, next time you overload it, instead of a 10 cent fuse blowing out, your variac may go up in smoke. Lots of smoke. Fuses are there for a reason, protection. Change them and your protection goes away.
If you put a 20 amp fuse to variac which burns a 7.5 ampere fuse which was originally installed, your variac might burn.
The weakest link in a Variac is the carbon commutator wiper (the part that rotates on the exposed adjustable winding). While the Variac may tolerate a 20 amp fuse rating for a short period of time - the wiper will soon burn out and become intermittent or open due to excessive current. Try a 7.5 amp slo-blow fuse instead of the conventional fuse. This will give the variac more surge protection and provide the same capacity as a higher rated fuse for a short period of time and still prevent permanent damage to the wiper/winding components.
Unfortunately not. If the current rating of a supply is 7.5amps, that's the max your gonna get. Putting a 20amp fuse in it will just possible cause the supply to burn up or possibly cause a fire. I definitely would not do this. If you were in a pinch and just want to test the supply, possibly you could, but again I wouldn't. Sorry
convinced, as said once you've #12/12 guage/awg 12 and with any luck all 3 wires you could positioned a 20 amp overcurrent protection gadget on the circuit with the only caveat being that on the bare minimum you've a minimum of one million 20 amp receptacle or a divided load and in case you extremely pick to be smart about it (or searching on what interpretation of which 12 months of the NEC you're going by ability of) you employ 20 amp receptacles through the homestead. Circuit Breaker AMPS twine length, length, and temperature AMPS receptacle AMPS. stick with the circuit. i'd improve each and everything and make certain no one cheated on the grounds everywhere.
