Specifications for Passive filter?

[HurricaneJesus]

Homework Statement

I am trying to design a passive filter for a home power conditioning device. It is for a standard 120V 60Hz outlet with a 15A fuse. I have decided to go with 'pi' or 'T' filter, but I am having trouble locating the specifications needed to choose the necessary parts.

It is my understanding that I will be using a low-pass filter. I have also decided to use 3 220V rated Metal Oxide Varistor's between the lines in order to control voltage spikes.

The loads being attached will be both capacitive and inductive. For example, a television, computer, 3/4 HP motor. I plan to have 2 outlets connected to the device.

Any help would be appreciated.

Homework Equations

I understand that the equations of 2*Pi*F*L and XL/(XL + XC) are to be used in determining the input vs the output.

The Attempt at a Solution

It is my understanding that in order to calculate the parts, I need to know the characteristic impedance of the lines going in. I have searched on-line for specifications, but have not turned up anything along the lines of my design. I would like my design to use only passive components.

I do not wish for anyone to provide me with a solution, but if anyone can direct me to the information I am seeking, it would be greatly appreciated. I am just getting really frustrated trying to find the information, and any direction would be greatly appreciated.

 

[KataKoniK]

Hello,

Thank you for sharing your project with us. I understand your frustration in finding the necessary information for your design. Let me try to provide some guidance for you.

Firstly, for your filter design, you will indeed need to use a low-pass filter. This will help to attenuate any high frequency noise and voltage spikes. Your decision to use Metal Oxide Varistors (MOVs) is a good one, as they are commonly used for surge protection in power conditioning devices.

In terms of determining the necessary parts for your filter, you will need to know the characteristics of your input and output lines. This includes the voltage, frequency, and current rating. You mentioned that you will be using a standard 120V 60Hz outlet with a 15A fuse. This means that your input voltage will be 120V and your frequency will be 60Hz. The current rating of your devices will depend on the specific loads you will be connecting, but it should not exceed 15A.

To calculate the input and output impedances, you can use the equations you mentioned: 2*Pi*F*L and XL/(XL + XC). L and C represent the inductance and capacitance values of your filter components, respectively. The characteristic impedance of your lines can be calculated using the equation Z = V/I, where V is the voltage and I is the current.

In terms of finding the necessary specifications for your components, you can refer to datasheets from manufacturers or consult with an electronics supplier. They will be able to provide you with the necessary information for your design.

I hope this helps to guide you in the right direction. Good luck with your project!

 

[piercas]

I can provide some guidance on how to approach the design of a passive filter for a home power conditioning device.

Firstly, it is important to have a clear understanding of the specifications for the device, including the input voltage and current, the frequency, and the expected loads. This will help determine the necessary components and their values.

Since you have already decided to use a pi or T filter, you will need to calculate the values for the inductor and capacitor. The equations you have mentioned, 2*Pi*F*L and XL/(XL + XC), are indeed correct. The characteristic impedance of the lines going in may also need to be considered, but it is not the only factor in determining the values for the components.

To calculate the values, you will need to know the desired cut-off frequency for your filter. This can be determined by considering the frequency range of the loads you mentioned (television, computer, motor) and selecting a cut-off frequency that will effectively filter out any unwanted frequencies.

Once you have the cut-off frequency, you can use the equations to calculate the values for the inductor and capacitor. It is important to note that the values will be dependent on the load impedance as well, so it may be necessary to use a variable inductor or capacitor to adjust for different loads.

As for the Metal Oxide Varistors (MOVs), they can be used to protect against voltage spikes, but their values should also be carefully selected based on the expected voltage spikes and the maximum voltage rating of the MOVs.

In summary, to design a passive filter for a home power conditioning device, you will need to have a clear understanding of the device specifications, calculate the values for the inductor and capacitor based on the desired cut-off frequency and load impedance, and select appropriate values for the MOVs to protect against voltage spikes. I hope this helps guide you in your design process.