Đồng hồ đo công suất Yokogawa 2041, 2042
Model 2041 single-phase wattmeters and single-phase low-power-factor wattmeters and Model 2042 three-phase wattmeters are electrodynamometer type wattmeters with indicators based on taut-band suspension. They can handle DC and frequencies from 25 Hz to 1000 Hz, and provide excellent power factor characteristics. These instruments are shielded with dual permalloy sheets as protection against external magnetic fields.