6
2.2.7. The limit of tolerable additional error of MT, caused by the effect of
constant magnetic fields and (or) variation fields of the circuit frequency of up
to 400 А/мvoltage, does not exceed 0,5 limit of the tolerable basic error.
2.2.8. The limit of the tolerable additional error of MT during exposure to
vibration does not exceed the limit of tolerable basic error.
2.2.9. The area of determining of settings corresponds to measuring range.
2.2.10. The limit of the tolerable basic error of actuation of the signalling
system does not exceed the last displayed digit of measured value.
2.2.11. Individual point relays of signalling channels support
commutation:
•of alternating current system frequency:
-at the voltage of 250 V till 5 Аon resistive load ,
-at the voltage of 250 V till 2 Аon inductive load (cos
≥0,4);
•of direct current:
-at the voltage of 250 V till 0,1 Аon resistive and inductive loads,
-at the voltage of 30 V till 2 Аon resistive and inductive loads.
Notes. On inductive load it is recommended to install spark suppression
circuits to the clamps of the instrument or to the inductive load
itself Spark suppression circuit should consist of series connected
реresistor 50…100 Ohm, 0,5 W and a capacitor 10…100 nF at the
voltage not less than 630 V.
2.2.12. The power supply of MT is carried out from alternating current
circuit with frequency (50±1) Hz and voltage of (220 +22 -33) V.
2.2.13. The power, consumed by MT from an alternating current circuit at
nominal voltage, does not exceed 20 V·А.
2.2.14. The insulation of electric circuits of MT between measuring
channels and relative to earthing clamp should hold out during 1 minute the
effect of testing voltage practically of sinusoidal shape with frequency from 45
up to 65 Hz:
- at normal conditions - 100 V and 1500 V accordingly;
-at the temperature of ambient air (35± 3) ºC and relative humidity
(95 ±3) % - 60 V and 900 V accordingly.
2.2.15. Electric resistance of insulation of current conducting circuits of
MT relative to its body and between the circuits themselves is not less then:
- 20 mOhm at the temperature of ambient air (20 ± 5) ºC and relative
humidity from 30 % up to 80 %;
- 5 mOhm at the temperature of ambient air (50±3) ºC and relative
humidity from 30 % up to 80 %;
