Determining the Air Gap Length of an Axial Flux Wound Rotor Synchronous Generator

The  air  gap  length  of  the  designed  axial  flux  wound  rotor  (AFWR)  synchronous  generator  is  determined  properly according to the design parameters. One of the distinct advantages of  an axial  flux (AF)  machine is  its adjustable air gap. An AF generator’s performance might be controlled by adjusting its air gap. The designed generator has a small-scale capacity that has 1 kW, 380 V, and 50 Hz. The windings are laid into slots made from laminated core. The slots are carved in the face of the stator and rotors. The generator has a single-double-sided slotted wound stator sandwiched between twin rotors. The effect of air gap changes on its  performance can be seen from the calculation results using the given equations. The results reveal electric quantities suited to the machine’s effective performance. The smaller the air gap,  the  greater  the  efficiency  and  power  factor  and  the  smaller  the  armature  current  and  voltage.  The  efficiency  and armature current for 0.1 cm air gap are 85.30 % and 1.815 A, respectively

Identification of Electrical Discharge on Electric Insulation Material Using Acoustic Emission Method

Insulation system is essential to be equipped on high voltage equipment. One of the tests on insulation system is the electrical discharge test. In this work, the electrical discharge detected using an acoustic emission method to find out the characteristic of the discharge. Epoxy resin was taken as the insulation material, whereas one to two artificial holes were made inside the insulation. An AE sensor placed at a distance of 24 mm and 36 mm away from holes or discharge source. The main frequency component of the detected AE signal on single hole test was approximately 975 kHz. Meanwhile, test on double holes caused two main frequency component; i.e. 63 kHz and 930 Khz. For single hole test and sensor distance of 36 m, the AE signal intensity tends to be worth 40% from the AE signal at a distance of 24 mm