Ques. For what service is a rotary converter better adapted than a rectifier?
Ans. For power distribution and other cases where a great amount of alternating current is to be converted into direct current, the rotary converter or large motor generator sets are more practical.
Ques. For what service is a rectifier especially adapted?
Ans. It is very desirable for charging storage batteries for automobiles from the local alternating current lighting circuit.
When the consumer installs and operates the apparatus for his own use and wear, there is considerable saving over motor generator sets because a small one to two horse power motor generator outfit has an efficiency of only 40 to 50 per cent. while mercury vapor rectifiers will have from 75 to 80 per cent.
Ques. What precautions should be taken in installing a rectifier?
Ans. It should be installed in a dry place and care should be taken to avoid dangling wires near the tube to prevent puncturing. If the apparatus be installed in a room of uniform moderate temperature very little trouble will be experienced in starting, while extreme cold will make starting more difficult.
[12]Electro-magnetic Rectifiers.—Devices of this class consist essentially of a double contact rocker which rocks on pivot (midway between the contacts), in synchronism with the frequency of the alternating current, so changing the connections at the instants of reversals of the alternating current that a direct current is obtained.
[12] NOTE.—The Edison electromagnetic rectifier is described in detail in Guide No. 4, pages 942 to 945.
Fig. 2,121 is a combined sketch and diagram of connections of a type of electromagnetic rectifier that has been introduced for changing alternating into direct current. The actual apparatus consists of a box, with perforated metal sides, about ten inches square and six inches deep. This box contains the step down transformer P,S,S', and the condensers K and K', the magnets and contact making device about to be described being fixed on the polished slate top of the box, exactly as shown in the figure. The transformer primary winding P may be connected through a switch s with a pair of ways on the nearest distribution box, or to a plug connection or lamp-holder, and the apparatus will give a rectified current of 6 or 12 amperes at 20 volts, according to the size.