The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
The stator inter-turn faults and stator electrical asymmetries such as stator resistance and inductance unbalance generate similar negative sequence current signatures in the induction machine. Hence the stator inter-turn fault is one of the most difficult faults to discriminate and detect in an induction machine. Discrimination of the stator inter-turn fault from stator electrical asymmetry essentially...
This paper proposes a new converter protection method, primarily based on a series dynamic resistor (SDR), that avoids the doubly-fed induction generator (DFIG) control being disabled by crowbar protection during fault conditions. A combined converter protection scheme based on the proposed series dynamic resistor and conventional crowbar is analysed and discussed. The main protection advantages are...
Many large turbo-generators today are now operating beyond their design lifetime, with careful condition-based maintenance and operation having extended their life expectancy. Monitoring the health of large turbo-generators is now an integral part of their operation. This paper describes the use of non-invasive electromagnetic sensors to detect core inter-lamination insulation faults in the stator...
The paper deals with special features related to the a.c. electric driving system of a trolley-bus. One presents the driving system consisting of an asynchronous motor and inverter and some aspects regarding the PWM inverter control. The tests over the manufactured asynchronous motor were performed at a frequency equal to 50 Hz (for the rated speed) and a frequency equal to 106.6 Hz corresponding...
The realization of a vector control for the operation of induction motors often takes advantage of ordinary equivalent circuit models. Some simplified models are consisting of a reduced number of system parameters and allow a very basically identification procedure by no-load tests in the lab. Fictive identification tests could fortunately be carried out by the finite element method during the development...
A comprehensive analysis of motor health may be accomplished by combining online and offline test results into fault zones. These fault zones are Power Quality, Power Circuit, Stator, Insulation, Rotor, and Air Gap. Power Quality focuses on the quality of the voltage and current. Power Circuit focuses on the power circuit supplying power to the motor. The Stator Fault Zone focuses on the turn-to-...
The sealed winding conformance test is often performed during the final acceptance test sequence for industrial motor stator insulation. The stator winding is first completely soaked with water, then receives a 10-minute insulation resistance (IR-io) measurement, followed by a 60-second high potential (hipot) test at 1.15 times rated line-to-line voltage (Vll). A 1-minute insulation resistance (IR-i)...
Prognosis for failure of an electric machine can be achieved through the detection of noncatastrophic faults. As the frequency of these types of faults increases, the working life of the machine is decreased, leading to eventual failure. In this work, two types of stator faults are studied. The methods developed are based on analysis of the short-time Fourier transform of the field oriented machine...
The analysis and performance characteristics for a low speed permanent magnet (PM) brushless transverse flux generator (TFG) have been discussed. This type of generator is a novel machine that can be manufactured in more cost effective way than standard PM brushless generators. The following issues have been emphasized: construction of a TFG, magnetic flux and stator winding EMF, resistance and synchronous...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.