Motor is widely used. Some friends don't know how thick the wire is when they connect the motor. In fact, as long as you know the power of the motor, you can quickly calculate the rated current. According to the current-carrying table of the conductor, you can determine the most appropriate conductor specifications.

Motor divided into single-phase motor and three-phase motor

Formula of Power and Current for 220 Volt Single Phase Motor

P=UIcosφ

P：Power of motor

U： voltage 220V=0.22KV

I：Working Current of Motor

cosφ：Working Current of Motor

：Motor efficiency (not less than 45%, generally energy-saving motor value of about 0.9)

The efficiency of motor is sometimes neglected in practical calculation.

From this we can calculate that the rated current of a 1KW single-phase motor is about 8A.

No-load current is more than 1/3 of rated current, low power can reach 2/3.

The calculation method of three-phase motor is slightly different.

P=√3UIcosφ

You can see one more.√3≈1.732

cosφPower factor: The greater the power, the greater the power factor.（0.7--0.9）

I=15÷（1.732×0.38×0.8）≈29A----(Just about twice the power)

Generally, three-phase motors above 4KW are triangular connection, so the rated current can be estimated directly by power * 2.