The nature of load current, l.e., whether load is continuous or discon...
The nature of load current in controlled rectifiers depends both on the type of load and the firing angle delay.Explanation:Type of Load
The nature of load current in controlled rectifiers is influenced by the type of load connected to the rectifier. The load can be either continuous or discontinuous.
Continuous Load
A continuous load draws a relatively steady and constant current from the rectifier. It is characterized by a constant or nearly constant load current throughout the entire half-cycle of the input voltage. Examples of continuous loads include resistive loads, incandescent lamps, and heaters.
Discontinuous Load
A discontinuous load draws current from the rectifier for only a portion of the half-cycle of the input voltage. The load current is interrupted during certain intervals of the input voltage cycle. Examples of discontinuous loads include inductive loads, capacitive loads, and loads with electronic switches.
Firing Angle Delay
The firing angle delay, also known as phase angle delay or firing delay, is the delay between the start of the input voltage cycle and the triggering of the thyristors in the controlled rectifier.
The firing angle delay controls the conduction period of the thyristors and, therefore, affects the load current waveform.
Combined Influence
The nature of the load current is determined by the combined influence of the type of load and the firing angle delay.
- For a continuous load, the load current can be continuous or discontinuous depending on the firing angle delay. If the firing angle delay is such that the thyristors conduct for the entire half-cycle of the input voltage, the load current will be continuous. However, if the firing angle delay is such that the thyristors conduct for only a portion of the half-cycle, the load current will be discontinuous.
- For a discontinuous load, the load current will be discontinuous regardless of the firing angle delay. This is because the load itself interrupts the current flow during certain intervals of the input voltage cycle.
Therefore, the nature of load current in controlled rectifiers depends both on the type of load and the firing angle delay. It is important to consider these factors when designing and analyzing controlled rectifier circuits.