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Thread: Amp meter install

  1. #1

    Amp meter install

    I got a analog amp meter with a shunt. Anyone have the proper way to install with shunt
    Thanks in advance
    Mitch

  2. #2
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    Quote Originally Posted by mitch stephens View Post
    I got a analog amp meter with a shunt. Anyone have the proper way to install with shunt
    Thanks in advance
    Mitch
    You mean a mA meter that reads 0 to 50 mA's, correct? Why would you use a shunt it just wires in the Negative or return side of the High Voltage lead to the tube. A mA is 1/1000's of a amp, and in this case its DC.
    Retired Guy- Central Iowa. , LightObject 40w CO2 Laser and Chiller, MakerGear M2 3D Printer. Qe60+ Vinyl cutter. Fine Line Automation 4x4 CNC Router- Mach3

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    Ammeters are usually millivolt meters with a precision resistor called a shunt. As current flows through the shunt, it generates a small voltage drop which is proportional to the current. The meter is calibrated in amps or milliamps but the actual measurement is a tiny voltage.

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    Quote Originally Posted by Art Mann View Post
    Ammeters are usually millivolt meters with a precision resistor called a shunt. As current flows through the shunt, it generates a small voltage drop which is proportional to the current. The meter is calibrated in amps or milliamps but the actual measurement is a tiny voltage.
    Regardless, have you ever seen a mA meter with an external shunt for measuring 0-50 mA? There are just two connections on any I have ever installed and its connected in series with the load.
    Retired Guy- Central Iowa. , LightObject 40w CO2 Laser and Chiller, MakerGear M2 3D Printer. Qe60+ Vinyl cutter. Fine Line Automation 4x4 CNC Router- Mach3

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    I am not sure where you are getting the idea that the meter in question is 0-50 mA. That value is no more common than a 0-1 mA or a 0-100 A meter. It just depends on what you are trying to measure. For example, if the original poster is wanting to measure the battery current in his travel trailer, such as I recently did, the most appropriate range in my case was 30A. In this case, an external shunt mounted near the battery was used. A remote millivolt meter using a twisted pair of leads mounted inside the coach was used as the readout. It was configured to measure both drain and charging current, which have opposite polarities. You are trying to use some specific application with which you are familiar as typical but it really isn't. You are absolutely correct that the shunt it always connected in series but it could just as well be mounted remotely as inside the meter.

    The original poster hasn't provided enough information so far to accurately answer his question.

    Quote Originally Posted by Bill George View Post
    Regardless, have you ever seen a mA meter with an external shunt for measuring 0-50 mA? There are just two connections on any I have ever installed and its connected in series with the load.

  6. #6
    'getting the idea' - because most Chinese laser tubes have an about 25-30mA upper limit, so an 0-50 is appropriate and I guess, normal. (my machine came with 0-30 meters FWIW)


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    I got the idea is was a mA meter since this is a Laser Forum not a trailer or car one. 0-50 or 0-30 mA is the most commonly installed on glass tube DC Chinese lasers. As an electrician I have installed hundreds of shunts and amp meters.

    A look back on his Recent posts shows he is replacing his 80 watt tube.
    Last edited by Bill George; 02-06-2019 at 2:30 PM.
    Retired Guy- Central Iowa. , LightObject 40w CO2 Laser and Chiller, MakerGear M2 3D Printer. Qe60+ Vinyl cutter. Fine Line Automation 4x4 CNC Router- Mach3

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    If this were a simple panel ammeter install, then why would the original poster be asking about shunts at all? That is why I am saying that he didn't furnish enough information to answer the question.

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    Art its pretty simple, my guess is he ordered the wrong meter as in one post he stated he was going to add a ammeter. We might never know as he is not posting.
    Retired Guy- Central Iowa. , LightObject 40w CO2 Laser and Chiller, MakerGear M2 3D Printer. Qe60+ Vinyl cutter. Fine Line Automation 4x4 CNC Router- Mach3

  10. #10
    Quote Originally Posted by Bill George View Post
    Art its pretty simple, my guess is he ordered the wrong meter as in one post he stated he was going to add a ammeter. We might never know as he is not posting.
    Yes after reading the replies I did order the wrong meter (0-30 amp) not MA and it came with a shunt. I reordered a 0-30ma meter that does not come with the shunt so I will assume It will not take one.
    Thanks for replies
    Mitch

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