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Non-contact voltage detection? — Parallax Forums

Non-contact voltage detection?

ArchiverArchiver Posts: 46,084
edited 2003-12-12 23:40 in General Discussion
Greetings all. I have a standby generator at work with an attitude
problem. Occasionally the transfer switch will start the generator,
but due to either the field or main breaker on the generator popping,
no power is supplied. The transfer switch is smart enough to
recognize that no power is being supplied by the generator and
prevent the switch from transferring.

The transfer switch has a set of dry contacts that I can use to tell
if it is in its exercise cycle, so I'm just looking for something
that will tell me if there is any power flowing through the lines
from the generator.

Is this something I can do with a Hall Effect sensor? I know that
there are all manner of current transformers available, and I'm
looking at that down the road to actually gather information on the
generator, but at this time I'm only looking to see if there is
current flowing down the wire.

Thanks in advance,
Brian

Comments

  • ArchiverArchiver Posts: 46,084
    edited 2003-12-12 19:38
    Greetings all. I have a standby generator at work with an attitude
    problem. Occasionally the transfer switch will start the generator,
    but due to either the field or main breaker on the generator popping,
    no power is supplied. The transfer switch is smart enough to
    recognize that no power is being supplied by the generator and
    prevent the switch from transferring.

    The transfer switch has a set of dry contacts that I can use to tell
    if it is in its exercise cycle, so I'm just looking for something
    that will tell me if there is any power flowing through the lines
    from the generator.

    Is this something I can do with a Hall Effect sensor? I know that
    there are all manner of current transformers available, and I'm
    looking at that down the road to actually gather information on the
    generator, but at this time I'm only looking to see if there is
    current flowing down the wire.

    Thanks in advance,
    Brian
  • ArchiverArchiver Posts: 46,084
    edited 2003-12-12 19:40
    Whoops. I'm not sure that it matters, but the generator is 480V 3
    phase, 125 KW. Inside the building it steps down to 120/208. I've
    got reasonably easy access to the lines on either side of the
    transformer.

    --- In basicstamps@yahoogroups.com, "Brian" <n7qjb@m...> wrote:
    > Greetings all. I have a standby generator at work with an attitude
    > problem. Occasionally the transfer switch will start the
    generator,
    > but due to either the field or main breaker on the generator
    popping,
    > no power is supplied. The transfer switch is smart enough to
    > recognize that no power is being supplied by the generator and
    > prevent the switch from transferring.
    >
    > The transfer switch has a set of dry contacts that I can use to
    tell
    > if it is in its exercise cycle, so I'm just looking for something
    > that will tell me if there is any power flowing through the lines
    > from the generator.
    >
    > Is this something I can do with a Hall Effect sensor? I know that
    > there are all manner of current transformers available, and I'm
    > looking at that down the road to actually gather information on the
    > generator, but at this time I'm only looking to see if there is
    > current flowing down the wire.
    >
    > Thanks in advance,
    > Brian
  • ArchiverArchiver Posts: 46,084
    edited 2003-12-12 20:42
    I've worked with rotary converters a bunch. An opto isolator is the best
    bet. Safe, small, easy to use.

    Note, when these units start up, they can draw tremendous amounts of
    current. Usually they start out as a squirrel cage motor, then change over
    to a synchronous motor. It could be the change over relay not sensing very
    close to synchronous, or a transient at the synchronous transfer that is
    causing it to pop.

    Original Message
    From: Brian [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=xmPvzu53bpF7Fyw6jMC1r44Cm_QXeVRja9ceJkNRl-HII3XycBEK2FyPugn4ELpQzFzEy-lTiw]n7qjb@m...[/url
    Sent: Friday, December 12, 2003 2:41 PM
    To: basicstamps@yahoogroups.com
    Subject: [noparse][[/noparse]basicstamps] Re: Non-contact voltage detection?


    Whoops. I'm not sure that it matters, but the generator is 480V 3
    phase, 125 KW. Inside the building it steps down to 120/208. I've
    got reasonably easy access to the lines on either side of the
    transformer.

    --- In basicstamps@yahoogroups.com, "Brian" <n7qjb@m...> wrote:
    > Greetings all. I have a standby generator at work with an attitude
    > problem. Occasionally the transfer switch will start the
    generator,
    > but due to either the field or main breaker on the generator
    popping,
    > no power is supplied. The transfer switch is smart enough to
    > recognize that no power is being supplied by the generator and
    > prevent the switch from transferring.
    >
    > The transfer switch has a set of dry contacts that I can use to
    tell
    > if it is in its exercise cycle, so I'm just looking for something
    > that will tell me if there is any power flowing through the lines
    > from the generator.
    >
    > Is this something I can do with a Hall Effect sensor? I know that
    > there are all manner of current transformers available, and I'm
    > looking at that down the road to actually gather information on the
    > generator, but at this time I'm only looking to see if there is
    > current flowing down the wire.
    >
    > Thanks in advance,
    > Brian


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  • ArchiverArchiver Posts: 46,084
    edited 2003-12-12 21:50
    Do you really care about current, or would voltage be enough?

    How about a simple relay across one of the circuits that "should" get
    emergency power? If the relay drops out, you've got problems and should go
    fix them.

    Original Message
    From: "Brian" <n7qjb@m...>
    To: <basicstamps@yahoogroups.com>
    Sent: Friday, December 12, 2003 11:40 AM
    Subject: [noparse][[/noparse]basicstamps] Re: Non-contact voltage detection?


    > Whoops. I'm not sure that it matters, but the generator is 480V 3
    > phase, 125 KW. Inside the building it steps down to 120/208. I've
    > got reasonably easy access to the lines on either side of the
    > transformer.
    >
    > --- In basicstamps@yahoogroups.com, "Brian" <n7qjb@m...> wrote:
    > > Greetings all. I have a standby generator at work with an attitude
    > > problem. Occasionally the transfer switch will start the
    > generator,
    > > but due to either the field or main breaker on the generator
    > popping,
    > > no power is supplied. The transfer switch is smart enough to
    > > recognize that no power is being supplied by the generator and
    > > prevent the switch from transferring.
    > >
    > > The transfer switch has a set of dry contacts that I can use to
    > tell
    > > if it is in its exercise cycle, so I'm just looking for something
    > > that will tell me if there is any power flowing through the lines
    > > from the generator.
    > >
    > > Is this something I can do with a Hall Effect sensor? I know that
    > > there are all manner of current transformers available, and I'm
    > > looking at that down the road to actually gather information on the
    > > generator, but at this time I'm only looking to see if there is
    > > current flowing down the wire.
    > >
    > > Thanks in advance,
    > > Brian
    >
    >
    > 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 2003-12-12 23:40
    When it operates, what is the minimum current passing through the line?
    Knowing this will help determine if the inexpensive hall effects available

    ken
    Is this something I can do with a Hall Effect sensor? I know that
    there are all manner of current transformers available, and I'm
    looking at that down the road to actually gather information on the
    generator, but at this time I'm only looking to see if there is
    current flowing down the wire.


    [noparse][[/noparse]Non-text portions of this message have been removed]
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