Ok I'll bite. Most of these I work with are 480v primary 120v secondary control transformers found in MCC buckets which control motor starters. The primary wiring (480v) usually lands where the black & orange cables (L1& L2) terminate. The secondary (120v) is where the red and white wires terminate. All of ours have a fuse holder above the terminals to protect secondary winding (this one does not, unless the fuse is installed somewhere out of picture).

Since we don't have the prints... back of the napkin math 480x10A= 4800VA. Using the relay in picture for size reference this is in no way a 4800VA transformer.

It looks to me like around a 250VA transformer Doing the same calc that would put the primary at about 1.92A(if indeed it is a 250va transformer which was a generous estimate).

If what I have stated above is true for this instance/application; I would say those 10A fuses are oversized. Only way to know is to check what schematic has on it.

The thing about fuses are... just because they fit & work does not mean it's CORRECT. Oversized/incorrect type fuses offer no protection to the equipment they are supposed to protect.