CENTRAL SCIENTIFIC CO., CHICAGO, U. 8. A. 



211 



Model 370. (See page 210.) 



Model 341. 



Model 310. 



METERS, WESTON (CONTINUED). 



VOLTMETERS, PORTABLE, Model 341. Those instruments are of the same general description 

 as the Model 370 Ammeters described on page 210. For ordinary measurements, no temperature 

 corrections are necessary. These instruments may be left in circuit continuously, but all ranges 

 above 5 volts are provided with locking contact keys by means of which the circuit may be 

 opened. The 1, 1.5 and 5 volt ranges have a small working error, but on the higher range in- 

 struments the working error is inappreciable. For both Alternating and Direct Current. 

 4576. VOLTMETERS, single range. 



No A B C D E F 



Range, volts 1 5 10 30 120 300 



Approx. resistance, ohms 2 18 66 470 2700 6700 



Each $81.25 81.25 78.15 75.00 75.00 78.15 



4578. VOLTMETERS, double range. 



No A B C 



Ranges, volts 15-1.5 120-60 300-150 



Approx. resistance, ohms 30-3 2700-1350 6700-3350 



Each 87.50 81.25 84.40 



WATTMETERS, PORTABLE SINGLE-PHASE, Model 310. These instruments represent the latest 

 development in electro-dynamometer wattmeters and have the same general description as the 

 Model 370 Ammeter described on page 210. The field coils are designed to stand double their 

 normal capacity continuously, and the potential circuits a voltage of 1% times their normal 

 value. A reversing switch is provided by.means of which the direction of the current through 

 the movable coil may be changed without changing the direction through the rest of the poten- 

 tial circuit. This makes it possible to obtain a positive deflection without changing connec- 

 tions. The scales are uniform throughout their entire length. For both Alternating and Direct 

 Current. 



4584. WATTMETERS, Single-phase, double voltage and current ranges, 

 volts, but will stand 300 and 150 volts without any damage. 



Rated voltages of 200 and 100 



No A B C D G 



Normal amperes, series 1 2.5 5 10 20 30 50 



Normal amperes, multiple 2 10 20 40 60 100 



Maximum amperes, series.... 2 5 10 20 40 60 75 

 Maximum amperes, multiple. . 4 10 20 40 80 120 150 

 Kilowatts, field coils in series 0.2 /O.l 0.5/0.25 1/0.5 2/1 4/2 6/3 10/5 

 Kilowatts, field eoils in mul- 

 tiple 0.4/0.2 1/0.5 2/1 4/2 8/4 12/6 20/10 



No. of scale lines 100 100 100 100 100 120 100 



Each 93.75 93.75 93.75 93.75 100.00 100.00 100.00 



WATTMETERS, PORTABLE POLYPHASE, Model 329. These instruments are of the same gen- 

 eral design as the Model 310 Single-Phase Wattmeters, but are larger, the dimensions being 

 0%xlO%x8 1/16 in. Each instrument consists of two single-phase wattmeters, electrically inde- 

 pendent, but having their movable coils mounted on a common shaft so thf.t they rotate together. 

 4586. WATTMETERS, Two-phase, double voltage and current ranges. Rated voltages of 200 and 100 

 volts, but will stand 300 and 150 volts without any damage. 



No. 



Normal amperes, series 



Normal amperes, multiple 



Maximum amperes, series 



Maximum amperes, multiple 



Kilowatts, field coils in series. . . 

 Kilowatts, field coils in multiple. 



No. of scale lines 



Each 



A 

 1 



2 



2 



4 



0.6/0.3 

 1.2/0.6 



120 

 143.75 



B 



2.5 



5 



5 



10 



1.5/0.75 



3/1.5 



150 



143.75 



C 



5 

 10 

 10 

 20 



3/1.5 



6/3 



150 



143.75 



D 



10 



20 



20 



40 



6/3 



12/6 



120 



150.00 



