How many amperes of fuses should be selected for the 315 transformer?trolling motor fuse

　　The low voltage current of the transformer is 453.6A (315KVA * 1.44=453.7A), and a fuse should be selected that is about twice as large.

　　The high-voltage current of the transformer is 12.6A (315 * 0.04=12.6A), and a fuse of 2-2.5 times should be selected. The content in parentheses is a simple calculation of the high and low voltage currents of transformers.

　　Due to the fact that the primary fuse of the transformer is used for short circuit protection (it cannot protect against overload on the low-voltage side), it is usually selected at a ratio of 1.5-2 times. As the load is only 270A, it is evident that there is no problem with heavy load startup. The load current is only 270A, so choosing 300A or 400A is sufficient.

　　If the capacity of a single motor carrying a load on a transformer is close to the capacity of the transformer, when selecting a secondary side fuse, a fuse specifically designed to protect the motor should be selected, and the size should also be selected according to the current close to the secondary side of the transformer. The fuse on the secondary side of the transformer should not only serve as short-circuit protection, but also protect the transformer from being burned by overload current. Therefore, it is generally necessary to select the fuse close to the secondary side current of the transformer (this is crucial for protecting the transformer).

　　315 Transformer Calculation Formula:

　　S=√ 3UI; The primary current is I=S/√ 3U=315000/1.732 * 6000=30.3A

　　Secondary current I=S/√ 3U=315000/1.732 * 380=478A

　　The selection of insurance should be 1.5 times the rated current for the first time, and 1.5~2 times the rated current for the second time to meet the requirements.

　　Calculation of primary and secondary currents of transformers:

　　S=√ 3UI;

　　The primary current is I=S/√ 3U=315000/1.732 * 6000=30.3A

　　Secondary current I=S/√ 3U=315000/1.732 * 400 (low voltage on the secondary side of the transformer is generally 400V)=455A

　　According to the above calculation formula, it can be concluded that the current of the transformer is generally selected as a fuse of 500A (450A).

Read recommendations:

plug with fuse inside

ceramic cartridge fuse

moulded plug fuse cover

The Application of Self Recovery Fuses in Automotive USB Systems.battery terminal fuse nissan problems

What are the principles for selecting fuses.resettable 15 amp fuse