Abstract: A defect detecting apparatus for monitoring an electrical equipment for defects, the electrical equipment having a resonance frequency.

Abstract: An abnormality detecting method and apparatus for electrical equipment measures the frequency spectrum of a signal detected by a partial discharge sensor and detects a partial discharge signal having a frequency component in the neighborhood of a resonance frequency to detect the abnormality of the electrical equipment. The resonance frequency is determined on the basis of the electrical equipment and the measuring circuit. Where the electrical equipment is a rotating electric machine, the resonance frequency is determined on the basis of the length of the stator core, and a narrow bandpass filter circuit passes a frequency component around a resonance frequency to detect a partial discharge signal from the passed signal.

Abstract: The abnormality detecting method and apparatus for electric equipment measure the frequency spectrum of a signal detected by a partial discharge sensor 9, and detect a partial discharge signal having a frequency component in the neighborhood of a resonance frequency determined on the basis of the electric equipment and its measuring circuit, then detect the abnormality of the electric equipment. In a rotating electric machine particularly, the narrow band filter circuit 23 passes a frequency component around a resonance frequency determined on the basis of the length of the stator core to detect a partial discharge signal from the passed signal.

Abstract: Sodium salts of phenylmalonic acid mono-esters are produced by reacting a phenylacetic acid ester with carbon dioxide in the presence of a sodium substituted compound, which is prepared by substituting a sodium atom for a hydrogen atom of an organic compound selected from a group consisting of acetylene, cumene, triphenylmethane, methyl-methylthiomethyl-sulfoxide and dimethyl-sulfoxide, at a temperature in a range of -20.degree. C. to -40.degree. C.

Abstract: Percent take-up feed of a yarn, which is taken up onto a pirn by rotary surface contact with a take-up roller via delivery rollers, is time-functionally and continuously changed by a speed converter which is inserted into a rotation transmission mechanism between both rollers and whose speed conversion ratio is adjusted by a pilot shaft in accordance with a programme which is designed on the basis of the take-up feed characteristic curve in order to obtain a yarn of uniform stretch property, the characteristic curve being in practice approximated by a combination of three or fewer straight lines.