We have a workshop – why were so many 220V solenoid valves chosen?
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We have a workshop – why were so many 220V solenoid valves chosen? Some people in the instrumentation field say this is nonsense ； The person in charge of the selection argued that choosing 220V was due to the distance between the control unit and the workshop, and also because there are many solenoids that require power; they were concerned that voltage drops might occur as a result. Is this true? I feel like I’m being deceived
Explosion-proof areas are generally powered by 24V; it depends mainly on the application scenario
There is no requirement to use 24VDC; as long as the explosion-proof rating is met, operation at 220VAC is more reliable than that at 24VDC.
The overall cost of using 220VAC is low, and it can be utilized if the site conditions permit. Currently, 24VDC is mainly used for safety reasons.
This post was last edited by tianya3047 on 2019-9-11 at 11:37. There is a problem of voltage attenuation, and the cable length must be taken into account for any signal. Since cables have resistance, proper design takes the cable length into account. When the power supply voltage drops to the minimum level required by the instrument, the signal becomes abnormal or it fails to start. The valve does not operate. However, solenoid valves rated at 220V are rarely used in instruments. Most instruments are powered by 24V DC. Line voltage drop also needs to be considered for 220V AC power supply. HG/T 20509—2000 \"Specifications for Instrument Power Supply Design\" also specifies the design requirements: for a 24V power supply, the voltage drop along the circuit should not exceed 0.24V ； For a 220V supply, the line voltage drop should not exceed 2V.
Distance is a factor that needs to be taken into account; too great a distance can indeed lead to voltage drop and abnormal operation of the solenoid valve. Two methods: 1. 220V AC power supply 2. With 24 V DC power supply, the cable should be thicker; for example, change from 1.5 to 2.5. In explosion-proof environments, the power must be turned off before the cover is opened.
The 2014 version does not specify any exact requirements; it only states that the voltage drop must meet the equipment’s specifications. Achieving a voltage drop of 0.24V is quite difficult. If the solenoid valve consumes 12W, then the backflow current will be around 0.5A, resulting in a circuit resistance of 0.48 ohms. How thick would the cable need to be for a length of about 200 meters?
There are low-power solenoids valves suitable for remote control; it is not necessary to use a 220V power supply