Electromagnetic flowmeters do not have a neutral wire
Thread Content
The electromagnetic flowmeter requires a power supply of 220V, but the distribution cabinet only has the live wire and the ground wire, without a neutral wire – it seems that someone forgot to run that wire. All of them currently have only 380V, with no 220V. The solution is to add a transformer to convert 380V to 220V, and then connect the resulting 220V power supply to the electromagnetic flow meter. May I ask if this wiring method will cause failures in the electromagnetic flowmeter? What about other flowmeters? Appendix: One electromagnetic flowmeter was damaged during use, and two rotameters experienced frequent malfunctions; it is not possible to determine whether this is due to power supply issues. Please advise.
Isn’t there 380V electricity? No transformer is needed; just use one of the phases, and by adding a ground wire, you get 220V
Ground wire cannot be used as the neutral wire, right? Otherwise, there wouldn’t be a five-wire system either.
Supplying power to “one line and one location” is strictly prohibited!
How does a transformer work? Does it still produce three-phase electricity?
Hehe. . . I am a instrumentation technician; I don’t understand electricity, but I have seen many electrical instrumentation panels, which are cabinets that contain a small number of instruments. All these electrical cabinets have three-phase power inputs; three live wires enter the circuit breaker and from there the wiring proceeds, with various circuit breakers being connected. A neutral wire is then present in the cabinet, as many devices require 220V power – such as lighting fixtures, alarms, exhaust fans, voltage stabilizers for instruments, various manual switches, relays, etc. – and all of these devices share a common neutral wire. So, where does this neutral wire come from? With a three-phase power supply connected to the cabinet, how can there be a neutral wire? ? There is no transformer in the cabinet.
Regarding the reasons mentioned by the poster for the burnout of electromagnetic flowmeters and the malfunctions of rotameters, I believe these are the drawbacks of placing instruments and electrical equipment in the same cabinet. Electric power refers to the power used for driving equipment; the start-up and shutdown of various electrical devices can cause voltage fluctuations. Instruments, on the other hand, require a relatively stable voltage supply and are not very tolerant to such fluctuations. In particular, some domestically produced instruments lack proper protection circuits against voltage surges, which increases the likelihood of electronic components being damaged as a result of these surges.
I wonder if the senior knows the difference between IT and TN power supply I’m not sure where you actually get it from; in all the zero-emission systems I’ve seen, a neutral wire is used for connection.
If it’s as the original poster said, an isolation transformer should be used, so the impact should be reduced.
I’m a newcomer; I came in to take a look and learn**