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power measurements — Parallax Forums

power measurements

ArchiverArchiver Posts: 46,084
edited 2003-04-24 15:41 in General Discussion
I made a power measurement for a 3 phase, whye connection, industrial
wave solder machine and obtained what I thought of as awkward data.
The power factor readings were as follows:

PF for L1 = -0.11
L2 = 1.00
L3 = 0.87

Is there an explanation for such a variation between each leg of a
single piece of equipment?

Thanks in advance

Comments

  • ArchiverArchiver Posts: 46,084
    edited 2003-04-23 22:50
    Unbalanced phases!

    Original Message
    From: "engrmaps" <engrmaps@y...>
    To: <basicstamps@yahoogroups.com>
    Sent: Thursday, April 17, 2003 4:33 PM
    Subject: [noparse][[/noparse]basicstamps] RE: power measurements


    > I made a power measurement for a 3 phase, whye connection, industrial
    > wave solder machine and obtained what I thought of as awkward data.
    > The power factor readings were as follows:
    >
    > PF for L1 = -0.11
    > L2 = 1.00
    > L3 = 0.87
    >
    > Is there an explanation for such a variation between each leg of a
    > single piece of equipment?
    >
    > Thanks in advance
    >
    >
    > To UNSUBSCRIBE, just send mail to:
    > basicstamps-unsubscribe@yahoogroups.com
    > from the same email address that you subscribed. Text in the Subject and
    Body of the message will be ignored.
    >
    >
    > Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
    >
    >
    >
  • ArchiverArchiver Posts: 46,084
    edited 2003-04-24 15:25
    sounds like the motor is single phasing.

    getting a -no load- on one phase means it is not connected. check
    the fuses, it may be that one fuse is blown on that phase.

    bet the motor is getting hot.

    If you are deaing with a variable speed drive, test it at a frequency
    above about 50 Hz. most amp probes are not designed for reading
    lower frequencies.

    Dave




    --- In basicstamps@yahoogroups.com, "engrmaps" <engrmaps@y...> wrote:
    > I made a power measurement for a 3 phase, whye connection,
    industrial
    > wave solder machine and obtained what I thought of as awkward
    data.
    > The power factor readings were as follows:
    >
    > PF for L1 = -0.11
    > L2 = 1.00
    > L3 = 0.87
    >
    > Is there an explanation for such a variation between each leg of a
    > single piece of equipment?
    >
    > Thanks in advance
  • ArchiverArchiver Posts: 46,084
    edited 2003-04-24 15:41
    These readings wouldn't be that far off if it were really 220/240 single
    phase and ground.

    Larry


    Original Message
    From: "Dave Mucha" <davemucha@j...>
    To: <basicstamps@yahoogroups.com>
    Sent: April 24, 2003 7:25 AM
    Subject: [noparse][[/noparse]basicstamps] Re: power measurements


    > sounds like the motor is single phasing.
    >
    > getting a -no load- on one phase means it is not connected. check
    > the fuses, it may be that one fuse is blown on that phase.
    >
    > bet the motor is getting hot.
    >
    > If you are deaing with a variable speed drive, test it at a frequency
    > above about 50 Hz. most amp probes are not designed for reading
    > lower frequencies.
    >
    > Dave
    >
    >
    >
    >
    > --- In basicstamps@yahoogroups.com, "engrmaps" <engrmaps@y...> wrote:
    > > I made a power measurement for a 3 phase, whye connection,
    > industrial
    > > wave solder machine and obtained what I thought of as awkward
    > data.
    > > The power factor readings were as follows:
    > >
    > > PF for L1 = -0.11
    > > L2 = 1.00
    > > L3 = 0.87
    > >
    > > Is there an explanation for such a variation between each leg of a
    > > single piece of equipment?
    > >
    > > Thanks in advance
    >
    >
    > To UNSUBSCRIBE, just send mail to:
    > basicstamps-unsubscribe@yahoogroups.com
    > from the same email address that you subscribed. Text in the Subject and
    Body of the message will be ignored.
    >
    >
    > Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
    >
    >
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