A 300VA transformer running on a 115Vac mains supply should be fused @ ~8A (300/115*3 = 7.8A), use a T8A fuse.
BUT !!!!!
that fuse will pass 16A for many seconds and maybe even a couple of minutes before it ruptures. That is a lot of heating power. That could be enough to set fire to your dorm !
What if your creation became faulty while you were not there and the Fire Chief discovered you had burnt down the student residence. Would your insurance cover you for being that incompetent?
Close rate the mains fuse, so that it provides effective protection against fire risk.
A close rated fuse is 2.6A (300/115 = 2.6A), use T2.5A, or smaller, if you can get reliable start up without nuisance blowing.
To enable start up with a close rated fuse you must use a soft start. If you try to use a T2.5A or T3.1A to start a 300VA transformer without soft start, you will get nuisance blowing.
BUT !!!!!
that fuse will pass 16A for many seconds and maybe even a couple of minutes before it ruptures. That is a lot of heating power. That could be enough to set fire to your dorm !
What if your creation became faulty while you were not there and the Fire Chief discovered you had burnt down the student residence. Would your insurance cover you for being that incompetent?
Close rate the mains fuse, so that it provides effective protection against fire risk.
A close rated fuse is 2.6A (300/115 = 2.6A), use T2.5A, or smaller, if you can get reliable start up without nuisance blowing.
To enable start up with a close rated fuse you must use a soft start. If you try to use a T2.5A or T3.1A to start a 300VA transformer without soft start, you will get nuisance blowing.
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Ok, I am going to use a soft start for sure then to eliminate the inrush current. I will look into a ~3amp slowblow fuse to keep everything in check.
Also, because I will be living with my amp in school I plan on making extra sure that everything is grounded and insulated. I should be allowed to have it as I am an electrical engineering student (haven't studied AC power supplies yet, hence the questions) and many upper classmen have DIY "toys" attached to the dorm mains.
Also, because I will be living with my amp in school I plan on making extra sure that everything is grounded and insulated. I should be allowed to have it as I am an electrical engineering student (haven't studied AC power supplies yet, hence the questions) and many upper classmen have DIY "toys" attached to the dorm mains.
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