Mains Bandstop FIlter

[[email protected]]

Hi All,

Im trying to find/ piece together a 250VAC bandstop filter circuit.

I'm trying to filter out a 1050Hz signal being put through the grid by
our energy supplier. The filter will be used specifically on a ceiling
fan (one filter for each).

The ceiling fans are rated at 250VAC and draws 250, 167 & 125 mA (AC)
at each of its three speeds.

Any idea where I can start? I need to be able to use well stocked
electronic components and have the circuit come in under $30
(Australian).

Cheers,
Daniel

 

[Phil Allison]

<[email protected]

Im trying to find/ piece together a 250VAC bandstop filter circuit.

I'm trying to filter out a 1050Hz signal being put through the grid by
our energy supplier. The filter will be used specifically on a ceiling
fan (one filter for each).

The ceiling fans are rated at 250VAC and draws 250, 167 & 125 mA (AC)
at each of its three speeds.

Any idea where I can start? I need to be able to use well stocked
electronic components and have the circuit come in under $30
(Australian).

** Looong time since I saw anyone ask for this one.

What I have seen published is parallel tuned circuit set to the tone's
frequency - like a 10 mH iron cored inductor with a 2.2 uF, 250 volt AC
cap in parallel. The " notch filter " is simply wired in series with the
fan motor.

This will produce a fairly high impedance at around 1050 Hz - but may not
provide enough attenuation on its own to do the job since the fan motor's
impedance will be high at that frequency too.

You could add a series RC ( ie Zobel network with say 2.2 uF and 100 ohms
10W ) or even a similar series tuned circuit ACROSS the motor to increase
attenuation if needed.

Jaycar sell a 9mH ferrite cored inductor ( cat: LF1336 ) for not too many
dollars intended for speaker x-overs so should easily handle the low current
you need.

YOU will have to experiment to get the filter onto the exact frequency.

You do have basic test gear for this - don't you ?



....... Phil

 

[Jim Thompson]

Hi All,

Im trying to find/ piece together a 250VAC bandstop filter circuit.

I'm trying to filter out a 1050Hz signal being put through the grid by
our energy supplier. The filter will be used specifically on a ceiling
fan (one filter for each).

The ceiling fans are rated at 250VAC and draws 250, 167 & 125 mA (AC)
at each of its three speeds.

Any idea where I can start? I need to be able to use well stocked
electronic components and have the circuit come in under $30
(Australian).

Cheers,
Daniel

What does "filter out" mean? Detect the presence of? Or remove?

...Jim Thompson

 

[Rich Grise]

Hi All,

Im trying to find/ piece together a 250VAC bandstop filter circuit.

I'm trying to filter out a 1050Hz signal being put through the grid by
our energy supplier. The filter will be used specifically on a ceiling
fan (one filter for each).

The ceiling fans are rated at 250VAC and draws 250, 167 & 125 mA (AC)
at each of its three speeds.

Any idea where I can start? I need to be able to use well stocked
electronic components and have the circuit come in under $30
(Australian).

I'd use a pi network, or maybe even something like a common-mode
choke with a couple of caps so it's parallel-resonant at 1050 Hz.

Good Luck!
Rich

 

[jasen]

Hi All,

Im trying to find/ piece together a 250VAC bandstop filter circuit.

I'm trying to filter out a 1050Hz signal being put through the grid by
our energy supplier. The filter will be used specifically on a ceiling
fan (one filter for each).

The ceiling fans are rated at 250VAC and draws 250, 167 & 125 mA (AC)
at each of its three speeds.

That's the stall current?

Any idea where I can start?

L-C notch filter

I need to be able to use well stocked
electronic components and have the circuit come in under $30
(Australian).

that'a a tough one, a suitable inductor rated to pass 250ma is likely to blow much of
that budget

Bye.
Jasen