It can be understood as the power of the transformer. This power is the apparent power, that is, the total power provided to the load. For resistive load, it can carry a load as large as the capacity of the transformer, but not for inductive load (motor), because there is still a problem of reactive power in it. You can check what is called reactive power on the Internet One or two words are not clear. Now there is no time. If you can't see clearly on the Internet, you can contact me. In short, no matter what load you carry (resistive or inductive, there is actually a capacitive load, but capacitive load is generally not seen). The larger the capacity of the transformer, the stronger the load capacity. The unit of the power transformer is generally KVA (read as kVA) Of course, his basic unit is VA, but this unit is very small So it's rarely used. Of course, the super large ones also have MVA, but it's not common. The biggest one used in our factory is 40000 KVA, and there are three 20000 KVA ones. The total capacity is 100000 kVA. How do you calculate the capacity when the voltage of 220 drops to 9? This can't be calculated directly. For example, you have two motors, one with rated voltage of 380V 1kW The other one is 380V 10kW. It can be seen that the rated voltage is the same but the power is different. Then you can't say that knowing the rated voltage can know the same power, that is to say, knowing the transformer's transformation ratio can't know its capacity!