Application Notes for Toroidal Transformers

author: KZ
14/09/2022
When selecting a toroidal transformer, the power of the toroidal transformer should be determined based on the voltage and current usage of the load. The nominal output current of a toroidal transformer is the output current at full load. When overloaded, the toroidal transformer can output more than 30% of the rated current. The overload capacity of toroidal transformers is very good, but the following two points need to be noted.

1. Used to start overloaded machinery and equipment

The current of some devices is rated during operation, but the current at startup is very large, sometimes exceeding 30%~50% of the rated current. For example, the overload capacity of an AC servo motor is usually designed to be 3 times the rated operating current. When the load starts, the current is large, which requires the toroidal transformer to be overloaded for a short time. Such a device with overloaded driving current is equipped with a toroidal transformer, and the rated output current of the transformer needs to be considered to exceed about 20% of the rated current of the device. Due to frequent start-up overloads, the temperature of the toroidal transformer rises, and the long-term transformer life becomes shorter.

2. Suitable for non-overload equipment

Many devices are designed with the maximum operating current in mind and the startup current does not need to be overloaded. For example, stepper motors are used as equipment power, and the operating current is the same as the starting current. When selecting a toroidal transformer, it is not necessary to design a margin for the output current of the toroidal transformer as long as the output current is equal to or greater than 10% of the maximum current of the stepper motor driver. Stepper motors never have overload current. In more work environments, the power of stepper motors is variable. This requires that voltage and current parameters should be determined during structural design, and reasonable power should be given artificially. In fact, the power of aWhen selecting a toroidal transformer, the power of the toroidal transformer should be determined based on the voltage and current usage of the load.
 toroidal transformer