Rectifier mechanical

Power Supply Electrical precipitators are generally energized by rectified alternating current of commercial frequency. The voltage is stepped up to the required value by means of a transformer and then rectified. The rectifying equipment has undergone an evolution which began with the synchronous mechanical rectifier in 1904 and was... 

PERMENORM. Nickel-iron alloy produced by magnetic annealing and drastic cold reduction and used for mechanical rectifiers and low-frcqucncy amplifiers. This alloy has a rectangular hysteresis loop that eliminates arcing at the contacts of mechanical rectifiers, as well as other desirable properties,... 

Several different exposures were made with 0.7 milliampere passing through the tube at a peak voltage of about 180,000 volts, using mechanically-rectified alternating current. The results are given in Table II. 

Smaller mechanical rectifiers of the six-phase type are built for a load of 5000 A with an efficiency approximating 95 per cent. In industry medium output units of twelve-phase type, built for a load of 10 000 A, having an efficiency of 98,8 per cent are used, or large units with 18 or even 24 phases and an efficiency practically equalling one. 

In this system, a hig)i-tension current, tanging from 7500 to 100000 volts, is applied to one electrode in the form of a wire, while the other electrode, a flat surface, is grounded. The current is direct, mechanically rectified... 

Electrostatic predpitatois for noncorrosive gas, minimum cost construction including collector plates, transformer, mechanical rectifier excluding foundation and supports. FOB cost = 900000 at inlet gas flow rate = 100 Nm /s with n =... 

The sample beam is chopped 90° out of phase with the reference beam, and after detection and amplification a synchronous mechanical rectifier on the chopper assembly discriminates against the signal from one beam and detects the signal that is in phase to send it to a dual-channel portion of the amplifier, where the signal is filtered. Then the ///o ratio is directly recorded on the L N strip chart modified potentiometric recorder. 

Dissolve 34 g. of o-nitroaniline in a warm mixture of 63 ml. of concentrated hydrochloric acid and 63 ml. of water contained in a 600 ml. beaker. Place the beaker in an ice - salt bath, and cool to 0-5° whilst stirring mechanically the o-nitroaniline hydrochloride will separate in a finely-divided crystalline form. Add a cold solution of 18 g. of sodium nitrite in 40 ml. of water slowly and with stirring to an end point with potassium iodide - starch paper do not allow the temperature to rise above 5-7 . Introduce, whilst stirring vigorously, a solution of 40 g. of sodium borofluoride in 80 ml. of water. Stir for a further 10 minutes, and filter the solid diazonium fluoborate with suction on a sintered glass funnel. Wash it immediately once with 25 ml. of cold 5 per cent, sodium borofluoride solution, then twice with 15 ml. portions of rectified (or methylated) spirit and several times with ether in each washing stir... 

P-Hydroxy-a-naphthaldehyde, Equip a 1 litre three-necked flask with a separatory funnel, a mercury-sealed mechanical stirrer, and a long (double surface) reflux condenser. Place 50 g. of p-naphthol and 150 ml. of rectified spirit in the flask, start the stirrer, and rapidly add a solution of 100 g. of sodium hydroxide in 210 ml. of water. Heat the resulting solution to 70-80° on a water bath, and place 62 g. (42 ml.) of pure chloroform in the separatory funnel. Introduce the chloroform dropwise until reaction commences (indicated by the formation of a deep blue colour), remove the water bath, and continue the addition of the chloroform at such a rate that the mixture refluxes gently (about 1 5 hours). The sodium salt of the phenolic aldehyde separates near the end of the addition. Continue the stirring for a further 1 hour. Distil off the excess of chloroform and alcohol on a water bath use the apparatus shown in Fig. II, 41, 1, but retain the stirrer in the central aperture. Treat the residue, with stirring, dropwise with concentrated hydrochloric acid until... 

In a 500 ml. wide-mouthed reagent bottle place a cold solution of 25 g. of sodium hydroxide in 250 ml. of water and 200 ml. of alcohol (1) equip the bottle with a mechanical stirrer and surround it with a bath of water. Maintain the temperature of the solution at 20-25°, stir vigorously and add one-half of a previously prepared mixture of 26-5 g. (25 -5 ml.) of purebenzaldehyde (Section IV,115) and 7 -3 g. (9-3 ml.) of A.R. acetone. A flocculent precipitate forms in 2-3 minutes. After 15 minutes add the remainder of the benzaldehyde - acetone mixture. Continue the stirring for a further 30 minutes. Filter at the pump and wash with cold water to eliminate the alkali as completely as possible. Dry the solid at room temperature upon filter paper to constant weight 27 g. of crude dibenzalacetone, m.p. 105-107°, are obtained. Recrystallise from hot ethyl acetate (2-5 ml. per gram) or from hot rectified spirit. The recovery of pure dibenzalacetone, m.p. 112°, is about 80 per cent. 

Hydrolysis of benzyl cyanide to phenylacetamide. In a 1500 ml. three-necked flask, provided with a thermometer, reflux condenser and efficient mechanical stirrer, place 100 g. (98 ml.) of benzyl]cyanide and 400 ml. of concentrated hydrochloric acid. Immerse the flask in a water bath at 40°. and stir the mixture vigorously the benzyl cyanide passes into solution within 20-40 minutes and the temperature of the reaction mixture rises to about 50°, Continue the stirring for an additional 20-30 minutes after the mixture is homogeneous. Replace the warm water in the bath by tap water at 15°, replace the thermometer by a dropping funnel charged with 400 ml. of cold distilled water, and add the latter with stirring crystals commence to separate after about 50-75 ml. have been introduced. When all the water has been run in, cool the mixture externally with ice water for 30 minutes (1), and collect the crude phenylacetamide by filtration at the pump. Remove traces of phenylacetic acid by stirring the wet sohd for about 30 minutes with two 50 ml. portions of cold water dry the crystals at 50-80°. The yield of phenylacetamide, m.p. 154-155°, is 95 g. RecrystaUisation from benzene or rectified spirit raises the m.p. to 156°. 

In a 700 ml. bolt-head flask, equipped with a reflux condenser and a mechanical stirrer, place 50 g. of benzophenone (Section IV,139), 500 ml. of rectified spirit, 50 g. of sodium hydroxide and 50 g. of zinc powder. Stir... 

Uncontrolled line side diode bridge rectifier. When a variable d.c. is required, it can be replaced by thyristors. Mechanical braking or non-regenerative braking-. 

The units and ancillary equipment must be protected from mechanical damage and the effects of weather to ensure the reliable operation of an impressed current station. This is achieved by installing it in a weatherproof plastic housing (see Fig. 8-2). Sufficient ventilation must be provided to disperse heat. The ventilation holes should be protected with brass gauze to keep out animals. Transformer-rectifier units must be connected to a circuit that is continuously energized, especially if they are in a building where the current is turned off at night, e.g., gas stations that are not open for 24 h. 

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