For efficiency and maximum performance 3 phase alternators are the most common alternators on the market, however due to the very nature of the design they are required to work at a balanced load. Unfortunately, it is almost impossible and unrealistic to run 3 perfectly balanced loads. Any variation on any of the loads will cause unbalance in the alternator. An unbalanced load can cause a number of unwanted effects on a alternator which can in-turn affect the load.
A key requirement for the alternator when driving isolated AC loads is to maintain a tight voltage regulation, a clean sinusoidal waveform and high efficiency over a range of load conditions. These conditions must also be met during the certain unbalanced loads that an alternator will experience. Voltage regulation should operate within ±5%, and Total Harmonic Disorder (THD) should be less than 5%. RFL Alternators has analysed the performance of unbalanced loads, in both star and delta configuration. Figure 1 illustrates the equivalent diagrams of these configurations.
A conventional alternator has a high source impedance. When operating at a full single phase load the input source impedance (the rotor winding impedance) becomes measurable with that of the phase impedance this will naturally cause a high voltage variation. In turn this could potentially burn out the rotor and stator windings.
In-order to overcome this supplier’s use an Automatic Voltage Regulator (AVR). This adds cost and complexity to the alternator, the AVR is an extra component in the system which will decreases the reliability of the Alternator. Furthermore, as the AVR tries to keep the voltage regulated on the loaded phase, the unloadedhttps://rflalternators.com/wp-content/uploads/2016/07/featured-image.jpg 300 550 Jason Clegg https://rflalternators.com/wp-content/uploads/2016/06/rfl_alternators_logo.png Jason Clegg2016-07-27 13:01:222017-10-10 07:02:15Unbalanced Loads