How many Gs is the AT in the PULLin VALUE of the reed switch?

一沙一世

How many Gs is the AT in the PULLin VALUE of the reed switch? [Copy link]

 

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As shown in the following figure:

In the working parameters of the reed switch, the unit AT in PULL in VALUE is equivalent to how many Gs

maychang

AT is not a unit of magnetic induction intensity, so it has nothing to do with Gs. Just like "chi" and "jin" have nothing to do with each other. You buy cloth by the foot, and rice by the jin. If you buy five feet of rice, you will be laughed at.

maychang

AT is the abbreviation of "ampere-turns" (according to your other post, it is stupid). In the table, 5AT means 5 amps and 1 turn is 5AT, 1 amp and 5 turns is also 5AT, and 0.1 amp and 50 turns is also 5AT.

maychang

The second to last line in your table clearly states that the number of turns of the test coil is 5000T, i.e. 5000 turns. So what does AT mean? Isn't it clear?

一沙一世

maychang posted on 2022-9-11 10:10 AT is the abbreviation of "ampere-turns" (according to your other post, it is stupid). 5AT in the table means 5 amperes per turn is 5AT, 1 ampere...

Thank you. Why doesn't the AT and reed switch's closing and opening directly show the magnetic field strength in GS or Tesla?

Is it hard to say whether this coil is put on the reed switch?

maychang

Yishayishi published on 2022-9-11 10:21 Thank you. Why can't the AT and the reed switch's attraction and disconnection be directly expressed in terms of the strength of the magnetic field, GS or ...

"Why not just express the magnetic field strength in GS or Tesla?"

This is the manufacturer's label of the reed switch. You can ask the manufacturer.

You should think about this: As a user, is it more convenient to measure the magnetic induction intensity at the location of the reed switch, or to measure the number of turns of the coil outside the reed switch?

maychang

Yishayishi published on 2022-9-11 10:21 Thank you. Why can't the AT and the reed switch's attraction and disconnection be directly expressed in terms of the strength of the magnetic field, GS or ...

"Is it possible that this coil is mounted on the reed switch?"

certainly.

The coil that drives the reed switch is not put on the outside of the reed switch. Where is it put?

jimtien

Ampere-turns (Ampere) is the unit of magnetomotive force. Dividing it by the length of the magnetic path gives the magnetic field strength (A/m).

一沙一世

maychang posted on 2022-9-11 10:27 "Why not directly show the strength of the magnetic field in GS or Tesla?" This is the mark of the reed switch manufacturer...

Thank you, I have never seen the method you mentioned. Our usage plan is:

So I'm not sure what form you are describing.

一沙一世

maychang posted on 2022-9-11 10:29 "Is it hard to say whether this coil is wrapped around the reed switch?" Of course. The coil that drives the reed switch is not wrapped around the outside of the reed switch, but...

Please refer to the above picture

maychang

Yishayishi published on 2022-9-11 11:45 Thank you, I have never seen the method you mentioned. Our usage plan is: So I don’t understand what you are describing...

This is the most common household tap water meter (flow meter).

In this case, you don't need to know the parameters of the reed switch, such as the ampere-turns. You just need to choose a reed switch, install it in the position you need, turn the pointer where the magnet is, and see if the reed switch can work reliably. Anyway, you don't know the parameters of the magnet, and there is no way to measure it.

maychang

Yishayishi published on 2022-9-11 11:45 Thank you, I have never seen the method you mentioned. Our usage plan is: So I don’t understand what you are describing...

"So I don't understand what form you are describing."

The simplest reed switch consists of two iron-nickel alloy sheets sealed inside a glass tube, as shown in Figures (01) and (02).

Picture (01)

Picture (02)

maychang

Yishayishi published on 2022-9-11 11:45 Thank you, I have never seen the method you mentioned. Our usage plan is: So I don’t understand what you are describing...

When a magnetic field is applied along the axis of the reed switch and the magnetic induction intensity reaches the Indian value, the two iron-nickel alloy sheets of the reed switch will be attracted together and the contacts will close.

The most common use of reed switches is to form relays. The method is to wind a coil around the reed switch. See Figure (03) and Figure (04). Note that the coil is a cross-section view.

Picture (03)

Picture (04)

maychang

Yishayishi published on 2022-9-11 11:45 Thank you, I have never seen the method you mentioned. Our usage plan is: So I don’t understand what you are describing...

This external magnetic field can of course also be generated by a permanent magnet. As the permanent magnet moves away from or closer to the reed switch, or at different angles, the reed switch can be closed or disconnected.

一沙一世

maychang posted on 2022-9-11 14:46 This external magnetic field can of course also be generated by a permanent magnet. As the permanent magnet moves away from or closes, or at different angles, the reed switch can be attracted or...

Thank you very much. Why do two reeds attract each other under the action of a magnetic field?

一沙一世

Also, are the magnetic field induction intensity when it is attracted and the magnetic field induction intensity when it is released the same value or not?

maychang

Yishayishi published on 2022-9-11 11:45 Thank you, I have never seen the method you mentioned. Our usage plan is: So I don’t understand what you are describing...

Our usage plan is:

Your plan is obviously to use the magnet on the third pointer of the water meter (0.01 cubic meter per grid) to control the action of the reed switch, and measure the water volume by the closing and opening of the reed switch (that is, the number of revolutions of the 0.01 cubic meter pointer, 0.1 cubic meter per revolution).

However, there is a force between the magnet and the reed switch, and this force must do work (otherwise the reed will not move). If the reed switch is made of soft magnetic material such as soft iron, then the hysteresis loss is very small and can be ignored. But I am not sure whether the energy absorbed by the reed switch can be ignored. If the energy absorbed by the reed switch is not negligible, then the reed switch will definitely affect the metering result of the water meter, making the flow rate smaller.

It is not known whether the authors of “our usage plan” have taken this impact into account.

maychang

Yishayishi published on 2022-9-11 11:45 Thank you, I have never seen the method you mentioned. Our usage plan is: So I don’t understand what you are describing...

Of course, this effect can be eliminated by adjusting the water meter, but you have added two more reed switches, which will require re-adjustment. Do you have the capability to do this?

maychang

Yishayishi published on 2022-9-11 11:45 Thank you, I have never seen the method you mentioned. Our usage plan is: So I don’t understand what you are describing...

The photo shows "Tai'an Hengfang Electronic Technology Co., Ltd.", a company that produces so-called "smart water meters."

When other manufacturers have already produced this product, you develop new products and want to grab the market?

maychang

Yishayishi published on 2022-9-11 14:51 Thank you very much. Why do two reeds attract each other under the action of a magnetic field?

"Why do two reeds attract each other under the influence of a magnetic field?"

Because the reeds are made of soft ferromagnetic material, when there is an external magnetic field, both reeds are magnetized and the magnetic field at the ends of the reeds is extremely uneven.