Designing a Tank Circuit for a 512 Hz Locator in Sewer Camera Inspection

In summary, designing a tank circuit for a 512 Hz locator in sewer camera inspection involves selecting a suitable inductor and capacitor to create a resonant frequency of 512 Hz. This frequency is used to locate underground pipes and other objects in sewer systems. The circuit must also be designed to have a high quality factor, allowing for accurate and precise measurements. Other considerations include the type of materials used, the size and placement of the circuit, and the overall reliability and durability of the design. Properly designing a tank circuit is crucial for the success and efficiency of sewer camera inspections.
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mess52
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I'm trying to help a Plummer friend out. I was once a pretty good Navy Tech with good component level trouble shooting skills, but that is long in the past and I have forgotten all of the math required to figure out even the most simple circuits. He has a sewer camera with a locator for it. He has attached a small wire to the camera cable and the wire is connected to a 512 Hz generator called a locator, but it doesn't work under ground. I'm thinking that a tank circuit is needed to develop the signal near the camera head, but I cannot remember how to do the math to figure our what component values to use. I also think that the "wire" he used should be a pair so that I have a feedback path to the generator. This circuit also needs to be very small in size as it could get caught in the pipes and come loose, however it is very low power, so that shouldn't be a problem I think. Can anyone help me out here?
 
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Is he trying to locate the camera underground? Usually this type of a locator is used to locate pipes underground.
 
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Sorry for the delay in response, had a hard time figuring out how to reply - I'm new to this. Anyway, he is trying to locate the camera inside the pipe. The camera goes down the pipe and when he finds damage to the pipe, he wants to locate the camera so he can mark where to dig to fix the problem.
 
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Assuming the robotic camera is tethered back to the controller. There is an easier way ... mark the tether off in metres/feet/yards whichever is your favourite
That's the way I have commonly seen pipe cameras used

Dave
 
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Dave, The problem with using a simple measurement for distance in the pipe is that pipes take a lot of twists and turns and ups and downs under ground. Jim, thanks for the formula, but as I stated before, I have not used this math in decades. I will follow the link you provided and see if I can figure it out. Also, I think that the reason they use such low frequency in these locators is due to the wave propagation through ground and pipes. I do know that they work because I have seen them work, I just don't know how to retrofit one onto an older camera that doesn't have it built into it. Thanks again.
 
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Jim, I just tried the calculator from your link. It is similar to others I have tried. It requires me to know the value of capacitance and inductance to give the resonant frequency. My problem is that I know the frequency, and have no idea what capacitance or inductance to use, or haw to make an educated guess at it. Do you know of another calculator out there that works the problem from the frequency to the required components?
 
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Dave, The problem with using a simple measurement for distance in the pipe is that pipes take a lot of twists and turns and ups and downs under ground.

that may be true, but in general and with all the pipes and cables I have had anything to do with,
their locations and depths are mapped and that info is generally held with those that laid the pipes etc. Therefore the distance along the pipe to the problem was the only totally unknown factor and for the ease of installation, they are generally laid as level and straight as possible

( yes ... OK I realize plans may have been lost or accidently destroyed :frown: )

Dave
 
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mess52 said:
Jim, I just tried the calculator from your link. It is similar to others I have tried. It requires me to know the value of capacitance and inductance to give the resonant frequency. My problem is that I know the frequency, and have no idea what capacitance or inductance to use, or haw to make an educated guess at it. Do you know of another calculator out there that works the problem from the frequency to the required components?

hmmmm that's a math question
with three terms it takes two of them to solve for the third one.
And you only know frequency.So, it'll be necessary to pick either a capacitance or an inductance .

If I plug into that calculator 512 for frequency
And 10e-6 for capacitance (10uf)
i get out 0.00966 henry, or 9.66 millihenry.

So, a 9.66 millihenry choke would resonate at 512 hz with a 10 uf capacitor.

It's probably more convenient to pick an available choke and make the necessary capacitance by paralleling smaller caps. That's because capacitors are cheaper than chokes. Especially in audio range where you need low resistance to give decent Q.
Remember your basics from Navy : Q=X/R

Something like this might work.
http://www.digikey.com/product-detail/en/1140-103K-RC/M8386-ND/774926
1140%20SERIES_sml.jpg

http://www.bourns.com/data/global/pdfs/1140_series.pdf

it's ten millihenries which resonates at 512hz with 9.66 microfarads, real close to a 5.0 and a 4.7 in parallel.
It's about an inch across so should fit down a pipe. The capacitors could be some distance away connected by a twisted pair, preferably shielded.
At that frequency you'll have X = about 31 ohms, the choke is 2.76Ω so Q is only a little over 10, not great but you might get away with it.
Higher current chokes (or audio crossover type from a speaker store) will do better but cost more.
...You've not said how your friend's gizmo excites the tank circuit

...but there's how to use the calculator, which was your question. Play with it a while or use your pocket calculator. Good luck , and keep us posted.

EDIT Hold on a second - Pocket calculator? What was i thinking - you're an old Navy guy. Dust off that Slide Rule !

old jim
 
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Jim, it is nice to know what the more expensive of the two components would be. I will work the problem from that angle. Your help is much appreciated! I will let you know what I come up with and how it works. Thanks again.
 

FAQ: Designing a Tank Circuit for a 512 Hz Locator in Sewer Camera Inspection

1. What is a 512 Hz tank circuit?

A 512 Hz tank circuit is an electrical circuit that consists of an inductor and a capacitor connected in parallel. It is called a "tank" circuit because the inductor and capacitor store energy, similar to a tank holding water. The 512 Hz refers to the frequency of the alternating current (AC) that the circuit is designed to resonate at.

2. How does a 512 Hz tank circuit work?

A 512 Hz tank circuit works by storing energy in the inductor and capacitor as the AC current alternates between positive and negative cycles. When the frequency of the AC matches the resonant frequency of the circuit, the energy stored in the inductor and capacitor is released, creating a strong oscillating current. This process repeats as long as the AC frequency remains at 512 Hz.

3. What is the significance of 512 Hz in a tank circuit?

The 512 Hz frequency is significant because it is the resonant frequency of the tank circuit. This means that the circuit is designed to vibrate or resonate at this frequency, resulting in a strong oscillating current. This frequency is commonly used in electronic devices, such as radios and televisions.

4. How is a 512 Hz tank circuit used in electronic devices?

A 512 Hz tank circuit is used in electronic devices to create a stable and strong oscillating current at the resonant frequency. This current can then be used for various purposes, such as filtering out unwanted frequencies, amplifying signals, or generating radio waves. The circuit can also be tuned to different frequencies by adjusting the values of the inductor and capacitor.

5. How do you calculate the resonant frequency of a 512 Hz tank circuit?

The resonant frequency of a 512 Hz tank circuit can be calculated using the formula f = 1/(2π√LC), where f is the resonant frequency in Hertz, L is the inductance in Henrys, and C is the capacitance in Farads. To achieve a resonant frequency of 512 Hz, the values of the inductor and capacitor must be carefully chosen based on the desired frequency and the properties of the circuit components.

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