Contactless Rotor Ground Fault Detection Method for Brushless Synchronous Machines Based on an AC/DC Rotating Current Sensor

Brushless synchronous machines (BSMs) are replacing conventional synchronous machines with static excitation in generation facilities due to the absence of sparking and lower maintenance. However, this excitation system makes measuring electric parameters in the rotor challenging. It is highly difficult to detect ground faults, which are the most common type of electrical fault in electric machines. In this paper, a ground fault detection method for BSMs is proposed. It is based on an inductive AC/DC rotating current sensor installed in the shaft. In the case of a ground fault in the rotating parts of the BSM, a fault current will flow through the rotor’s sensor, inducing voltage in its stator. By analyzing the frequency components of the induced voltage, the detection of a ground fault in the rotating elements is possible. The ground faults detection method proposed covers the whole rotor and discerns between DC and AC sides. This method does not need any additional power source, slip ring, or brush, which is an important advantage in comparison with the existing methods. To corroborate the detection method, experimental tests have been performed using a prototype of this sensor connected to laboratory synchronous machines, achieving satisfactory results.This research was funded by Universidad Politécnica de Madrid under grant number RP2304330031

Comparative Study of Infliximab Versus Adalimumab in Refractory Uveitis due to Behçet's Disease: National Multicenter Study of 177 Cases.

To compare the efficacy of infliximab (IFX) versus adalimumab (ADA) as a first-line biologic drug over 1 year of treatment in a large series of patients with refractory uveitis due to Behçet's disease (BD). We conducted an open-label multicenter study of IFX versus ADA for BD-related uveitis refractory to conventional nonbiologic treatment. IFX or ADA was chosen as the first-line biologic agent based on physician and patient agreement. Patients received 3-5 mg/kg intravenous IFX at 0, 2, and 6 weeks and every 4-8 weeks thereafter, or 40 mg subcutaneous ADA every other week without a loading dose. Ocular parameters were compared between the 2 groups. The study included 177 patients (316 affected eyes), of whom 103 received IFX and 74 received ADA. There were no significant baseline differences between treatment groups in main demographic features, previous therapy, or ocular sign severity. After 1 year of therapy, we observed an improvement in all ocular parameters in both groups. However, patients receiving ADA had significantly better outcomes in some parameters, including improvement in anterior chamber inflammation (92.31% versus 78.18% for IFX; P = 0.06), improvement in vitritis (93.33% versus 78.95% for IFX; P = 0.04), and best-corrected visual acuity (mean ± SD 0.81 ± 0.26 versus 0.67 ± 0.34 for IFX; P = 0.001). A nonsignificant difference was seen for macular thickness (mean ± SD 250.62 ± 36.85 for ADA versus 264.89 ± 59.74 for IFX; P = 0.15), and improvement in retinal vasculitis was similar between the 2 groups (95% for ADA versus 97% for IFX; P = 0.28). The drug retention rate was higher in the ADA group (95.24% versus 84.95% for IFX; P = 0.042). Although both IFX and ADA are efficacious in refractory BD-related uveitis, ADA appears to be associated with better outcomes than IFX after 1 year of follow-up