Due to the wide use of gearmotor systems in industry, many diagnostic techniques have been developed/employed to prevent their failures. An insufficient lubrication of gearboxes of these machines could shorten their life and lead to catastrophic failures and losses, making it important to ensure a required lubrication level. For the first time in worldwide terms, this paper proposed to diagnose a lack of gearbox oil lubrication using motor current signature analysis (MCSA). This study proposed, investigated, and experimentally validated two new technologies to diagnose a lack of lubrication of gear motor systems based on MCSA. Two new diagnostic features were extracted from the current signals of a three-phase induction motor. The effectiveness of the proposed technologies was evaluated for different gear lubrication levels and was compared for three phases of motor current signals and for a case of averaging the proposed diagnostic features over three phases. The results confirmed a high effectiveness of the proposed technologies for diagnosing a lack of oil lubrication in gearmotor systems. Other contributions were as follows: (i) it was shown for the first time in worldwide terms, that the motor current nonlinearity level increases with the reduction of the sgearbox oil level; (ii) novel experimental validations of the proposed two diagnostic technologies via comprehensive experimental trials (iii) novel experimental comparisons of the diagnosis effectiveness of the proposed two diagnostic technologies.
This paper proposes, investigates, and validates, by comprehensive experiments, new online automatic diagnostic technology for belt conveyor systems based on motor current signature analysis (MCSA). Motor current signature analysis (MCSA) is a method employed for detecting faults in electric motors by analyzing the current waveforms generated during motor operation. The technology capitalizes on the fact that motor defects, such as mechanical misalignment, bearing damage, and rotor bar defects, cause variations in a motor’s current waveforms, which can be discerned and analyzed using advanced signal processing techniques. MCSA is a non-invasive and cost-effective technique that can detect motor faults in real-time without requiring expensive equipment or disassembly of the motor. In this study, the researchers tested the proposed diagnostic technology, which relies on a power feature. The power feature is calculated as the integrated power within a specific frequency range, centered around the fundamental harmonic of the supply frequency. The purpose of the study is to evaluate for the first time the effectiveness of the proposed diagnostic technology for the diagnosis of a tracking of a belt conveyor. The proposed technology’s effectiveness is assessed using current signals that are obtained for two different scenarios: the normal belt tracking, and a belt mis-tracking under two different loads of a belt conveyor system. The study’s findings indicate that the proposed technology has a high level of diagnostic effectiveness when used for belt mis-tracking. Therefore, it is feasible to recommend this technology for diagnosing tracking issues in belt conveyors.
For the first time ever worldwide, this paper proposes, investigates, and validates, by multiple experiments, a new online automatic diagnostic technology for the belt mis-tracking of belt conveyor systems based on motor current signature analysis (MCSA). Three diagnostic technologies were investigated, experimentally evaluated, and compared for conveyor belt mis-tracking diagnosis. The proposed technologies are based on three higher-order spectral diagnostic features: bicoherence, tricoherence, and the cross-correlation of spectral moduli of order 3 (CCSM3). The investigation of the proposed technologies via comprehensive experiments has shown that technology based on the CCSM3 is highly effective for diagnosing a conveyor belt mis-tracking via MCSA.
Myeloablative allogeneic hematopoietic transplantation continues to be performed as an inpatient procedure from the start of the preparative regimen until neutrophil recovery in most centers. Advances in supportive care and improved remission status pre-transplant may enable predominantly outpatient management of such patients during their transplant. We have analyzed transplant outcomes for consecutive unselected allogeneic transplants performed at our center between February 2005 and June 2006. Patients were scheduled to be admitted to the inpatient unit for less than one day for the stem cell infusion. The remainder of the transplant procedure including the preparative regimen and the period of pancytopenia prior to hematopoietic recovery were managed in the outpatient setting. Patients were admitted to the inpatient BMT unit for the management of complications only. Outpatient care was performed in a dedicated, fully HEPA-filtered facility with detailed infection control measures. If necessary, patients were admitted directly to the inpatient unit and use of the emergency department of the hospital was avoided. Patients were assessed daily for a minimum of 28d post HCT. Fifty-nine patients underwent first allogeneic HCT using non-cord blood donors during the period (median age 41 (21–63); 41 M, 18F; diagnoses - AML=17, ALL=11, NHL=8, MDS/MPS=7, MM=6, HD=2, OTH=7; Myeloablative=35, RIC =24; Related donors=38, MUD=21; ASBMT disease risk score - high=39, intermediate=4, low=16. Median inpatient stay from start of preparative regimen to d100 was 18d (1–63d). With a median follow-up of 565d (383–873d) for all patients, estimated probability of overall survival (OS) at 100d, 12m and 24m are 95%, 80% and 58% respectively. Corresponding probabilities of non-relapse mortality (NRM) are 3.5%, 14% and 23%. For patients undergoing myeloabative HCT, OS and NRM probabilities were 96%, 78%, 58% and 5%, 16%, 22% respectively. The HCT-comorbidity index (HCT-CI, Sorror et al Blood106:2912 [2005]) was used to assess co-existing morbidities. Probabilities of OS and NRM by HCT-CI risk group are shown in the Table. These data suggest that planned outpatient management of allogeneic HCT including myeloblative HCT can be performed without compromising OS and NRM if the appropriate facilities are provided. HCT-CI 0 1–2 ≥3 Overall Survival d100 100% 97% 83% p=NS 12m 87% 81% 67% Non-Relapse Mortality d100 0% 3% 9% p=NS 12m 10% 14% 20%
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