 The proper application of a bus structure requires a knowledge of the bus ratings and the service conditions under which the bus structure is to be used. With this knowledge, it is possible to select the proper bus structure for the requirements of the application in question. The rating of a bus structure is a designated limit of operating characteristics based upon definite conditions. The rating of a bus structure includes the following items: Rated Voltage The rated voltage of a bus structure is the highest nominal system voltage at which it is designed to operate. Rated Frequency The rated frequency of a bus structure is the frequency at which it is designed to operate. Rated Continuous Current The rated continuous current of a bus structure is the current in amperes at a rated frequency, which it will carry continuously without exceeding the limit of a specified temperature rise. Rated Momentary Current The rated momentary current of a bus structure, (or rms) is the total current which the bus will be required to carry. Withstand-Test Voltage A withstand-test voltage is a voltage which a bus structure must withstand, without flash-over or other electrical failure, when the voltage is applied under specific conditions. For low frequency voltage, the values are expressed in rms, and are for a specific time. For impulse voltage, the values are expressed in crest of a specified wave. Ambient Temperatures Standard bus structure is suitable for operation where the ambient temperature does not exceed 40º C. |
