Testing my filterette
- Bangle 99
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Testing my filterette
The inside of my filterette looks pretty clean in that my capacitors don’t appear to have been leaking. They’re marked 55A 6-30v. How do I test them to see if they’re still good?
James D Teel II
Retired Police Sergeant/Bomb Tech
SFC OKARNG
Edmond, Oklahoma
MVPA 30889
'43 Willys MB/ITM jeep
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James D Teel II
Retired Police Sergeant/Bomb Tech
SFC OKARNG
Edmond, Oklahoma
MVPA 30889
'43 Willys MB/ITM jeep
<><
James Teel
Police Sergeant/Bomb Tech-Ret.
SFC OKARNG-Ret.
Edmond, Oklahoma
'43 Willys MB/ITM jeep
‘42 SS Cars lightweight trailer
<><
Police Sergeant/Bomb Tech-Ret.
SFC OKARNG-Ret.
Edmond, Oklahoma
'43 Willys MB/ITM jeep
‘42 SS Cars lightweight trailer
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Re: Testing my filterette
Here is what I would do. Using a DMM set to measure ohms, verify very each cap measures infinite resistance from lug to ground. There may be an initial low reading if the DMM is charging the caps but they should quickly read open. Then set DMM to capacitance measurement setting if it has that capability and verify the capacitance measures close to the rated amount. The next test is the most important in my opinion. Connect to a power supply at least double your expected application voltage so 12 or 24 volts. Connect a DMM in series to measure current and verify no leakage current with maximum voltage applied. Caps often fail by developing an electrical leakage path to ground and will blow fuses if bad enough. I'm not sure what the technology used for these were since I have not opened one but presume they are some sort of foil with paper in oil dielectric so should be pretty durable and long wearing.
Ed Fallon
GPW 1943 91901 DOD 1-8-43 restoration in progress
GPW 1943 91901 DOD 1-8-43 restoration in progress
- Bangle 99
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Re: Testing my filterette
Thank you.Jeep Fun wrote:Here is what I would do. Using a DMM set to measure ohms, verify very each cap measures infinite resistance from lug to ground. There may be an initial low reading if the DMM is charging the caps but they should quickly read open. Then set DMM to capacitance measurement setting if it has that capability and verify the capacitance measures close to the rated amount. The next test is the most important in my opinion. Connect to a power supply at least double your expected application voltage so 12 or 24 volts. Connect a DMM in series to measure current and verify no leakage current with maximum voltage applied. Caps often fail by developing an electrical leakage path to ground and will blow fuses if bad enough. I'm not sure what the technology used for these were since I have not opened one but presume they are some sort of foil with paper in oil dielectric so should be pretty durable and long wearing.
James D Teel II
Retired Police Sergeant/Bomb Tech
SFC OKARNG
Edmond, Oklahoma
MVPA 30889
'43 Willys MB/ITM jeep
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James Teel
Police Sergeant/Bomb Tech-Ret.
SFC OKARNG-Ret.
Edmond, Oklahoma
'43 Willys MB/ITM jeep
‘42 SS Cars lightweight trailer
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Police Sergeant/Bomb Tech-Ret.
SFC OKARNG-Ret.
Edmond, Oklahoma
'43 Willys MB/ITM jeep
‘42 SS Cars lightweight trailer
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- YLG80
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Re: Testing my filterette
Agree with Jeep Fun test method.
For the second part of the test which is a dynamic test, put your filterette is a safe place during the test , away from small parts, glass etc ...
Just in case one capacitor decides to explode.
This is not very dangerous, but it could project long strips of paper, oil , asphalt and other strange matters everywhere
Carefully check if there is a leakage current after a few hours.
If any, it will discharge your jeep battery when she is sleeping in your garage !
Yves
For the second part of the test which is a dynamic test, put your filterette is a safe place during the test , away from small parts, glass etc ...
Just in case one capacitor decides to explode.
This is not very dangerous, but it could project long strips of paper, oil , asphalt and other strange matters everywhere
Carefully check if there is a leakage current after a few hours.
If any, it will discharge your jeep battery when she is sleeping in your garage !
Yves
Ford GPW 1943 - Louisville - DoD 12-7-43
serial 164794
serial 164794
- twinflyer17
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Re: Testing my filterette
The reason my filterette isn't connected. I bypassed it to avoid that risk. It's still mounted for show, though, and no one would know unless they unbolted it from the firewall
- Bangle 99
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Re: Testing my filterette
Did you pull the capacitors out or just connect the wires, insulate them, and put the cover back on?
James D Teel II
Retired Police Sergeant/Bomb Tech
SFC OKARNG
Edmond, Oklahoma
MVPA 30889
'43 Willys MB/ITM jeep
<><
James Teel
Police Sergeant/Bomb Tech-Ret.
SFC OKARNG-Ret.
Edmond, Oklahoma
'43 Willys MB/ITM jeep
‘42 SS Cars lightweight trailer
<><
Police Sergeant/Bomb Tech-Ret.
SFC OKARNG-Ret.
Edmond, Oklahoma
'43 Willys MB/ITM jeep
‘42 SS Cars lightweight trailer
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- dpcd67
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Re: Testing my filterette
I do not trust these antique pieces of "electronics" and bypass them; I just make connections under the dash, hidden by the filterette case. I considered, removing the guts and connect the wires in side the case but I left the capacitors in on my GPW. I have a Dodge in the works now and I am not sure how I am going to wire that. It has a filterette too.
U. S. Army 28 years.
Armor Branch
Armor Branch
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Re: Testing my filterette
I’m going to install a working WS19 in my jeep. I will have a complete set of grounding straps. Any idea how much interference I’ll have if I bypass the filterette?
James D Teel II
Retired Police Sergeant/Bomb Tech
SFC OKARNG
Edmond, Oklahoma
MVPA 30889
'43 Willys MB/ITM jeep
<><
James D Teel II
Retired Police Sergeant/Bomb Tech
SFC OKARNG
Edmond, Oklahoma
MVPA 30889
'43 Willys MB/ITM jeep
<><
James Teel
Police Sergeant/Bomb Tech-Ret.
SFC OKARNG-Ret.
Edmond, Oklahoma
'43 Willys MB/ITM jeep
‘42 SS Cars lightweight trailer
<><
Police Sergeant/Bomb Tech-Ret.
SFC OKARNG-Ret.
Edmond, Oklahoma
'43 Willys MB/ITM jeep
‘42 SS Cars lightweight trailer
<><
- YLG80
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Re: Testing my filterette
I've just measured my filterette leakage current :
I measure a total leakage of 3.3 mA.
When a disconnect my electronic 6V regulator, the leakage is < .05 mA which is the filterette leakage. This is just nothing.
Please note that the big boxes in the filterette contains not only capacitors but also coils/chokes.
In fact the capacitor values in each box are likely of a low value which reduces the risk of leakage and explosion.
I've never opened any filter unit like that, but I guess that the capacitors are not of the electrolytic type which is the most unstable when very old.
These caps are likely of the paper+oil type which are much more stable.
Each one of the three boxes inside the filterette contains a coil with two capacitors to form a high current (up to 10A) shielded PI filter for the 0-30Mhz range.
Schematic of the filter group. The WS19 is an Amplitude Module radio, so you should use radio filters in your jeep.
AM radios are a nightmare regarding radio suppression.
If you bypass the filterette, you should add capacitors as suppressors. (see other G503 threads on radio interference suppression).
The filterette has a much higher performance because it is made of LC pi filters (inductance L + capacitor C filter)
So with a by-passed filterette, I would install at least an LC filter in the WS19 power supply line.
If you have a very low current leakage with your filterette, I would certainly used it.
There is another solution if you want to be "absolutely sure" of your hardware :
Remove the 3 filterette elements,buy 3 modern DC line filters and install them in the filterette original box .
The modern filter are much smaller than the vintage ones .
Yves
I measure a total leakage of 3.3 mA.
When a disconnect my electronic 6V regulator, the leakage is < .05 mA which is the filterette leakage. This is just nothing.
Please note that the big boxes in the filterette contains not only capacitors but also coils/chokes.
In fact the capacitor values in each box are likely of a low value which reduces the risk of leakage and explosion.
I've never opened any filter unit like that, but I guess that the capacitors are not of the electrolytic type which is the most unstable when very old.
These caps are likely of the paper+oil type which are much more stable.
Each one of the three boxes inside the filterette contains a coil with two capacitors to form a high current (up to 10A) shielded PI filter for the 0-30Mhz range.
Schematic of the filter group. The WS19 is an Amplitude Module radio, so you should use radio filters in your jeep.
AM radios are a nightmare regarding radio suppression.
If you bypass the filterette, you should add capacitors as suppressors. (see other G503 threads on radio interference suppression).
The filterette has a much higher performance because it is made of LC pi filters (inductance L + capacitor C filter)
So with a by-passed filterette, I would install at least an LC filter in the WS19 power supply line.
If you have a very low current leakage with your filterette, I would certainly used it.
There is another solution if you want to be "absolutely sure" of your hardware :
Remove the 3 filterette elements,buy 3 modern DC line filters and install them in the filterette original box .
The modern filter are much smaller than the vintage ones .
Yves
Ford GPW 1943 - Louisville - DoD 12-7-43
serial 164794
serial 164794
- Bangle 99
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Re: Testing my filterette
Thank you. You’ve been a lot of help.
James D Teel II
Retired Police Sergeant/Bomb Tech
SFC OKARNG
Edmond, Oklahoma
MVPA 30889
'43 Willys MB/ITM jeep
<><
James D Teel II
Retired Police Sergeant/Bomb Tech
SFC OKARNG
Edmond, Oklahoma
MVPA 30889
'43 Willys MB/ITM jeep
<><
James Teel
Police Sergeant/Bomb Tech-Ret.
SFC OKARNG-Ret.
Edmond, Oklahoma
'43 Willys MB/ITM jeep
‘42 SS Cars lightweight trailer
<><
Police Sergeant/Bomb Tech-Ret.
SFC OKARNG-Ret.
Edmond, Oklahoma
'43 Willys MB/ITM jeep
‘42 SS Cars lightweight trailer
<><
- twinflyer17
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Re: Testing my filterette
Left the capacitors, but connected the like wires and wrapped in electrical tape. Then mounted the full filterette box over top of them. Didn’t torque it down too hard, though, so that I wouldn’t bend the filterette’s mounting ears or crimp the wires. It’s been 2+ years and no issues.
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Re: Testing my filterette
Going to agree with Sean to by-pass the filterette. These things were the high tech of the day, ( 70 years ago) but age takes it's toll.
The filter part is the capacitors in Yves picture and notice, they are connected between B+ and ground.
The capacitors absorb energy spikes that give off RF interference that messes up radios and is detectable by the enemy with directional receivers. This is bad !!
When functioning normally, the capacitors absorb the high frequency spikes and slowly ( Ha ! Ha!. We are dealing with electricity moving at the speed of light ) dissipates the absorbed energy to ground. Helps suppress the unwanted RF signals. Keeps the C.O.'s radio clear and in the old days, these signals messed up the approach radar around airports. That would get you pulled over and your car impounded.
As noted, these capacitors are sealed inside a can ?? Kinda like a hand grenade. Right next to your passengers knee ??
If one of the capacitors short to ground, which after 70 years is a real possibility, it is gonna blow and someone may get hurt. Also bad !!
By passing the filter as Sean said or converting them as Yves suggested is a good idea !
Black tape ? I would suggest crimped butt connectors and heat shrink tubing for the by-pass connections.
The filter part is the capacitors in Yves picture and notice, they are connected between B+ and ground.
The capacitors absorb energy spikes that give off RF interference that messes up radios and is detectable by the enemy with directional receivers. This is bad !!
When functioning normally, the capacitors absorb the high frequency spikes and slowly ( Ha ! Ha!. We are dealing with electricity moving at the speed of light ) dissipates the absorbed energy to ground. Helps suppress the unwanted RF signals. Keeps the C.O.'s radio clear and in the old days, these signals messed up the approach radar around airports. That would get you pulled over and your car impounded.
As noted, these capacitors are sealed inside a can ?? Kinda like a hand grenade. Right next to your passengers knee ??
If one of the capacitors short to ground, which after 70 years is a real possibility, it is gonna blow and someone may get hurt. Also bad !!
By passing the filter as Sean said or converting them as Yves suggested is a good idea !
Black tape ? I would suggest crimped butt connectors and heat shrink tubing for the by-pass connections.
Mike Wolford
CJ-2A
VEP GPW
Comm./Inst. SEL
AOPA ( 50 yrs)
EAA ( 49 yrs)
4th Inf. Div. - 5th Inf. Div. - 2nd Armor Div. - CIB
CJ-2A
VEP GPW
Comm./Inst. SEL
AOPA ( 50 yrs)
EAA ( 49 yrs)
4th Inf. Div. - 5th Inf. Div. - 2nd Armor Div. - CIB
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- Bangle 99
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Re: Testing my filterette
Your filterette will not ever explode. It’s not anything like a grenade. The most that will ever happen is you’ll have a short to ground that will cause a battery drain. That’s what happens when they fail.
There’s also no oil in them.
If anyone on this forum has actually ever witnessed one first hand fail by exploding, please raise your hand. It’s going to be a long wait.
James Teel
Retired Police Sergeant/Bomb Tech
SFC OKARNG
Edmond, Oklahoma
MVPA 30889
'43 Willys MB/ITM jeep
‘42 SS Cars lightweight trailer
<><
There’s also no oil in them.
If anyone on this forum has actually ever witnessed one first hand fail by exploding, please raise your hand. It’s going to be a long wait.
James Teel
Retired Police Sergeant/Bomb Tech
SFC OKARNG
Edmond, Oklahoma
MVPA 30889
'43 Willys MB/ITM jeep
‘42 SS Cars lightweight trailer
<><
James Teel
Police Sergeant/Bomb Tech-Ret.
SFC OKARNG-Ret.
Edmond, Oklahoma
'43 Willys MB/ITM jeep
‘42 SS Cars lightweight trailer
<><
Police Sergeant/Bomb Tech-Ret.
SFC OKARNG-Ret.
Edmond, Oklahoma
'43 Willys MB/ITM jeep
‘42 SS Cars lightweight trailer
<><
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Re: Testing my filterette
James
I was going on what Yves said about them containing oil and paper.
So it is a leakage issue I was concerned about. PCBs are really really nasty.
Back in those days, they used all sorts of chemicals that are now banned.
If you have taken apart a filterette, what was inside the capacitors?
Regards
Doug
I was going on what Yves said about them containing oil and paper.
So it is a leakage issue I was concerned about. PCBs are really really nasty.
Back in those days, they used all sorts of chemicals that are now banned.
If you have taken apart a filterette, what was inside the capacitors?
Regards
Doug
Bangle 99 wrote: ↑Sat May 01, 2021 4:25 amYour filterette will not ever explode. It’s not anything like a grenade. The most that will ever happen is you’ll have a short to ground that will cause a battery drain. That’s what happens when they fail.
There’s also no oil in them.
If anyone on this forum has actually ever witnessed one first hand fail by exploding, please raise your hand. It’s going to be a long wait.
James Teel
Retired Police Sergeant/Bomb Tech
SFC OKARNG
Edmond, Oklahoma
MVPA 30889
'43 Willys MB/ITM jeep
‘42 SS Cars lightweight trailer
<><