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MRI CT Scanners and DNO Voltage fluctuations.

Ian King

How are older (6-10 years) MRI CT scanners running in the UKs Hospitals coping with Line voltage peaks exceeding 440 volts rms ?

Is it fair to link peaks like this on PV on sunny days even in winter ?

Ian King MIET.

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    Do you mean 440 phase to phase on 3 phase, or L-N (as if any one phase)? The former is 10% up on a nominal 230/400 and  I would expect anything well designed to ride that out, medical or not, while  the latter would suggest some serious fault,
    PV will reverse the direction of the voltage drop in the wiring to it when generating, so long thin feeder runs are unwise, as they drive up the voltage at the end where the PV connects and that can be the limit on how much you can push in.. (*)
    Mike

    edited for typos and clarity.

    Edit
    * this is also another  reason it is recommended that PV circuits have their own submain if not back to the origin then at  least back to a point where the supply impedance is low enough and/or  there are enough loads pulling down so that the voltage rise under generation conditions does not become  an issue.

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  • 0

    Do you mean 440 phase to phase on 3 phase, or L-N (as if any one phase)? The former is 10% up on a nominal 230/400 and  I would expect anything well designed to ride that out, medical or not, while  the latter would suggest some serious fault,
    PV will reverse the direction of the voltage drop in the wiring to it when generating, so long thin feeder runs are unwise, as they drive up the voltage at the end where the PV connects and that can be the limit on how much you can push in.. (*)
    Mike

    edited for typos and clarity.

    Edit
    * this is also another  reason it is recommended that PV circuits have their own submain if not back to the origin then at  least back to a point where the supply impedance is low enough and/or  there are enough loads pulling down so that the voltage rise under generation conditions does not become  an issue.

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