. Journal of electricity, power, and gas . anding tothe customers credit, is placed on the attachment. When the first coin is deposited and the knob is turned,closing the main switch, the pointer rests opposite the firstdivision on the scale. If a second coin is deposited beforethe current purchased with the first coin has been consumed,a second motion of the knob will bring the pointer oppositethe second division on the scale. Twelve coins can thus bedeposited consecutively, after which the slot is automaticallyclosed and further prepayment cannot be made until thevalue of one or more coins h
. Journal of electricity, power, and gas . anding tothe customers credit, is placed on the attachment. When the first coin is deposited and the knob is turned,closing the main switch, the pointer rests opposite the firstdivision on the scale. If a second coin is deposited beforethe current purchased with the first coin has been consumed,a second motion of the knob will bring the pointer oppositethe second division on the scale. Twelve coins can thus bedeposited consecutively, after which the slot is automaticallyclosed and further prepayment cannot be made until thevalue of one or more coins has been consumed. Whenever energy to the value of one coin has been de-livered through the meter, the escapement is released (me-chanically in the combined device, and electrically in theseparate device) turning the pointer back one division. Thisprocess continues until all the energy for which prepaymenthas been made has been delivered. Thus the depositor canascertain at any time how much energy can be obtainedwithout further Fig. 2. Thomson Higli Torque Watt-Hour Meter witllSeparate Prepayment Device—Type IP—for Alter-nating Current. When all the energy has been delivered, the circuitswitch is opened and no more current can be obtained untilfurther prepayment has been made. The indicating mechanism shows only the number ofcoins which stand to the credit of the customer; but byconsulting the meter dial one can determine what frac-tional part remains of the prepayment next to be cancelled. The actuating force which operates the device is a largeflat coil spring enclosed in a barrel or drum to which itsoutside end is attached. The operating knob winds this mainspring by turning the drum. The spring has many turnsand as the operation of the device never equals one wholeturn, the spring always exerts a practically constant force. The rate device consists of a small train of gears securedto the front of the frame directly back of the register, thegear ratio dependi
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Keywords: ., bookcentury1800, bookdecade1890, bookidjo, booksubjectelectricity
