The purpose of the electrical transfer switch we need is that ATSE can automatically and reliably convert under "specific" conditions. This "specific condition" is the conversion condition of ATSE, or the premise of conversion, is the first choice to consider the elements of ATSE.
1. If common power has no failure, dual power automatic transfer switch can not change.
This is a problem many users (and even manufacturers) have ignored. The controller of double power supply automatic changeover switch must be able to identify the instantaneous fluctuation of various voltage, including short time voltage loss of non power supply fault. For example, the low voltage power distribution center of the transformer substation switch is a normal power supply interruption, should not be switched off when the parent switch to determine the power failure, the need to be able to determine the "normal" power. The controller must pass the EMC test, not to be able to operate under external electromagnetic interference. Note: the conversion condition is decided by the function of the controller, to determine the way of power failure (including fault type identification) is the core technology of the controller, the general product information is not introduced, see manufacturers research level and industry experience, designers need to understand the judgment mechanism of product.
2. Must be converted in power fault conditions.
However, due to many types of power failure (more than a dozen), it is necessary to identify those faults must be converted. Because of the complexity of user requirements, the general controller vendors provide a variety of functions, therefore, the design must according to the load on the power quality requirements clearly indicate the conversion condition, otherwise, because the double power automatic switch market supply of chaos and the owners of ATSE do not know much, leading to the final use of the product is often only in the loss of power complete a condition to conversion, and other power failure (including phase, under voltage, etc.) will not lose the meaning of conversion,. Note: because the dual power automatic transfer switch function is still not standardized design only indicate product model, can not guarantee that users understand the conversion of selected types of conditions, resulting in product design and practical use of the proposed design requirements of a larger, indicate the conversion condition. For example, the lack of any phase, over-voltage, under voltage, frequency deviation, harmonics, etc., of which the need for an arbitrary phase transition is the minimum requirements. High end controller, and even the ability to check the quality of two-way power supply, automatic access to higher power quality power supply.