Discussion on power supplies for explosion-proof weighing instruments
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It is an explosion-proof weighing display with an explosion protection rating of Exd(ia II C GA)IIB T6 Gb; however, the rated voltage indicated in the notes section is AC220V. The model remains unchanged. Is it possible to modify it to operate at DC24V, while still being able to use the same explosion protection certificate? Does this meet the explosion protection specifications?
It is possible. This explosion protection rating refers to that of the control box used in the field; the power supply you require is for the secondary instruments inside. Generally, manufacturers will install a DC24V rail-mounted switching power supply within the box, with this switching power supply being used to convert AC220 voltage to DC24V. Of course, it is also possible to supply power to the secondary instruments directly from a DCS or PLC.
It depends on the sample; is discussion needed?
As long as the supply voltage to the secondary instruments does not exceed the 220VAC voltage specified on the nameplate of the explosion-proof enclosure, there will be no problems; this should be noted in the inventory record of the instrumentation equipment
This specification states that, after explosion-proof instruments are installed in explosion-proof instrument boxes, they must be considered as a whole in order to meet the explosion-proof requirements.