Wattmeter D57 (D 57, D-57).
Wattmeter D57 - a device with a six-limits for measurement of active electric power in single-phase AC, 50 Hz. The device is used as a model and accurate laboratory measurements.
Technical features of D57:
- Accuracy class - 0.1;
- The current in the device - 30mA;
- Voltage 220V;
- Available in 4 versions, with the following limits of current: 0.5 - 1A, 2 - 4A, 2.5 - 5 A, 5 - 10A.
By principle wattmeters D57 are ferrodinamicheskim devices. The basic error in all of the scale at nominal operating conditions does not exceed ± 1,5% of full scale value.
Rated power factor for power meter D57 cos φ = 1, the settling time moving part - ≤ 4 sec.
Changing the readings under the influence of different factors have the following meanings:
- By rejecting ambient temperature of 20 ± 5 ° C (class H) does not exceed ± 0,8% for every 10 degrees
- Under the influence of an external magnetic field of 400 A / m - not exceed ± 2,5%;
- Due to the influence of uneven phase load - not exceed ± 1,5%.
Average lifetime D57 at least 12 years
Wattmeters D57 correspond to GOST 8476-60 and TU 25-04-165-67
D57 wattmeter is used at an ambient temperature of -40 ° C to +50 ° C and relative humidity of 95% (at 35 ° C). Allows operation at a temperature of from -50 to +60 ° C and relative humidity of 95% (at 60 ° C). In terms of resistance to mechanical stress they are vibration and tryaskoprochnym.