I think you mean how to reset the transformer core. Basically after the application of a volt-second product the core flux has built up to some value. To reset the core to zero flux an equal but opposite volt-second product must be applied.
If 1 volt is applied for 1 second the volt -second product is 1 V-s. To reset the core -1 volt for 1 second can be applied. Or -100 volts for 0.01 seconds can be applied.
Never use a foil on a blow fuse your lucky it did not burn something else and you could not recoil a transformer you have to get a new one same model since this one is molded in a plastic case.
Never use a foil on a blow fuse your lucky it did not burn something else and you could not recoil a transformer you have to get a new one same model since this one is molded in a plastic case.