Twentieth century hand-book for steam engineers and electricians with questions and answers; a practical non-technical treatise .. (1913)
Swingle, Calvin Franklin, 1846- [from old catalog] · Chicago, F. J. Drake & company · leaf 1341
Fig. 615switch boakd ammeter … Fig. 616illuminated dial instrument The instrument shown in Fig. 614 has an extra handending in a ring. This can be set at the voltage it isdesired to maintain. The most hasty glance will then showwhether the voltage is too high or too low. Electro Meters 1313 In order to save space on switchboards…
