. Dental electro-therapeutics. of wires to aprimary coil of a small transformer fitted to the produces a low-voltage current which passes throughthe secondary coil of the transformer, from which it is con-veyed by means of a sliding contact. A graduated currentis by this means obtained to suit voltage and amperage ofthe various instruments. The only disadvantage of the motor converter method isthat a small motor is necessary, in addition to the switch-board, but all trouble of attending to accumulators, theneed of heavy resistance coils, and the unavoidable heatingare done awa
. Dental electro-therapeutics. of wires to aprimary coil of a small transformer fitted to the produces a low-voltage current which passes throughthe secondary coil of the transformer, from which it is con-veyed by means of a sliding contact. A graduated currentis by this means obtained to suit voltage and amperage ofthe various instruments. The only disadvantage of the motor converter method isthat a small motor is necessary, in addition to the switch-board, but all trouble of attending to accumulators, theneed of heavy resistance coils, and the unavoidable heatingare done away with; moreover, all risk of shocks to eitherpatient or operator is entirely avoided. If desired, the motor can be put out of the way in a boxor cupboard, or it may be placed in another room and con-trolled by a switch on the switchboard. In addition to thespecial work for which it is intended it can also be usedin the operating room as a lathe, when not employed forgenerating the low-voltage current. THE MOTOR CONVERTER 131. Fig. 58.—Switchboard. 132 DENTAL ELECTRICAL APPLIANCES By this method the low-voltage circuit only is convertedto alternating current; the high-voltage continuous currentcircuit remains unaffected and always available for motorpower. A modern switchboard is shown in Fig. 58. This is sup-plied either with the direct resistance or with the motorconverter. When the motor converter is employed themotor is fitted for use as an operating-room lathe and thusanswers a double purpose.
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Keywords: ., bookauthor, bookcentury1900, bookdecade1910, booksubjectdentistry
