Forums :: Resources :: Features :: Photo Gallery :: Vintage Radio Shows :: Archives
Support This Site: Contributors :: Advertise


It is currently Oct Mon 14, 2019 10:05 pm


All times are UTC [ DST ]





Post New Topic Post Reply  [ 19 posts ] 
Author Message
 Post subject: schematic for CLC filtered power supply wanted
PostPosted: Apr Wed 03, 2019 9:47 pm 
Member

Joined: Jan Fri 04, 2019 11:32 pm
Posts: 34
Location: Sheridan, Wyoming
I have made a bridge rectifier, CLC power supply, and do not know diddly squat about how to choose the electrolytic cap values for the caps on each side of the filter choke. I have checked the books, the internet, etc. It always seems easier for me to look at a schematic, and just copy that schematic. My Edcor transformer is a120 volt primary/ 230 volt secondary, no center tap transformer,with a 12.6 volt filiment winding. Somewhere there is a power supply already designed out there, or there is someone to show me a step by step procedure to calculate the cap values. Any help appreciated......William


Last edited by williampage on Apr Thu 04, 2019 11:16 pm, edited 1 time in total.

Top
 Profile  
 
 Post subject: Re: schematic for CLC filtered power supply wanted
PostPosted: Apr Wed 03, 2019 9:52 pm 
Member
User avatar

Joined: Jul Mon 26, 2010 8:30 pm
Posts: 26565
Location: Annapolis, MD
We need to start with the requirements:
Output voltage?
Maximum current?
Allowable ripple?

Are you sure you need a choke? Capacitors these days are pretty cheap, but chokes are not.

_________________
-Mark
"Measure voltage, but THINK current." --anon.


Top
 Profile  
 
 Post subject: Re: schematic for CLC filtered power supply wanted
PostPosted: Apr Wed 03, 2019 10:28 pm 
Member

Joined: Jan Thu 01, 1970 1:00 am
Posts: 7605
Location: Minneapolis, MN USA
Previous discussion for the OP and topic:
viewtopic.php?f=12&t=352318&p=2968401#p2968401


Top
 Profile  
 
 Post subject: Re: schematic for CLC filtered power supply wanted
PostPosted: Apr Thu 04, 2019 11:15 pm 
Member

Joined: Jan Fri 04, 2019 11:32 pm
Posts: 34
Location: Sheridan, Wyoming
My configuration ended with a 350 volt DC supply. I was trying to get as close to 250 volts as possible. I used a bridge rectifier with two 82mf electrolytics, with a 5 Hy, 50ma. choke in between the 2 caps. I have one 100K 2 watt bleeder resistor for each electrolytic cap. My transformer is an EDCOR XPWR119-120. The input for this xfmr is 120v @ 60Hz, and output is 240 volts @200 ma.The filament winding is 12.6 volts @ 3 amps.The tubes which I am using are two 12sk7gt, one 12sj7gt, and one 12v6gt. The 4 tubes draw .270 amp.total. My needs are the 250 volts with .270 amps for the radio circuit. I could use some help here! I do not know what level of ripple would be ok here. Thanks.......William


Top
 Profile  
 
 Post subject: Re: schematic for CLC filtered power supply wanted
PostPosted: Apr Thu 04, 2019 11:28 pm 
Member
User avatar

Joined: Jul Mon 26, 2010 8:30 pm
Posts: 26565
Location: Annapolis, MD
I think your 350 must be a typo---even 250 seems like a stretch for that big a load.

How do you get 270 mA for those four tubes??---I would have guessed well under 100mA

_________________
-Mark
"Measure voltage, but THINK current." --anon.


Top
 Profile  
 
 Post subject: Re: schematic for CLC filtered power supply wanted
PostPosted: Apr Thu 04, 2019 11:37 pm 
Member

Joined: Jan Fri 04, 2019 11:32 pm
Posts: 34
Location: Sheridan, Wyoming
I will check this out tonight, and try to figure out how to get the load for all 4 of the tubes. I wrote in .270, not 270 amps. At this point, I feel totally lost, and cannot go forward until I get this figured out. If you know how to do this, how about figuring the amps needed for two 12sk7gt tubes, one 12sj7gt tube, and one 12v6gt tube? Or. Could you direct me to a site which lists, in order, the steps to accomplish this?????????William


Last edited by williampage on Apr Thu 04, 2019 11:48 pm, edited 1 time in total.

Top
 Profile  
 
 Post subject: Re: schematic for CLC filtered power supply wanted
PostPosted: Apr Thu 04, 2019 11:45 pm 
Member
User avatar

Joined: Jul Mon 26, 2010 8:30 pm
Posts: 26565
Location: Annapolis, MD
0.270 amps is 270mA----the total for those tubes should be well under 100.

Voltage:
For 240 rms, the peak is 339 volts. That is the highest DC voltage you can get---with 100% rectification efficiency. Something like 80% is more common---that would put you at 271.

By any chance, did you use a doubler?----or perhaps 350 was the no-load voltage? If so, check the no-load AC voltage.

_________________
-Mark
"Measure voltage, but THINK current." --anon.


Top
 Profile  
 
 Post subject: Re: schematic for CLC filtered power supply wanted
PostPosted: Apr Thu 04, 2019 11:50 pm 
Member

Joined: Jan Fri 04, 2019 11:32 pm
Posts: 34
Location: Sheridan, Wyoming
350 was the no load voltage. When I leave the library today, I will check the AC secondary voltage before it reaches the bridge rectifier. I think it was about 350, when I checked it a day or so ago! I think that I may be making it hard on myself. It probably is simplier than I think, but I just have not figured out the steps to reach my desired results. I am not stupid, but ignorant about this!!!!!!!!William


Last edited by williampage on Apr Thu 04, 2019 11:59 pm, edited 1 time in total.

Top
 Profile  
 
 Post subject: Re: schematic for CLC filtered power supply wanted
PostPosted: Apr Thu 04, 2019 11:53 pm 
Member
User avatar

Joined: Jul Mon 26, 2010 8:30 pm
Posts: 26565
Location: Annapolis, MD
And the no-load AC voltage was ?

And---how did you get 270mA for the tubes?

_________________
-Mark
"Measure voltage, but THINK current." --anon.


Top
 Profile  
 
 Post subject: Re: schematic for CLC filtered power supply wanted
PostPosted: Apr Fri 05, 2019 12:02 am 
Member

Joined: Jan Fri 04, 2019 11:32 pm
Posts: 34
Location: Sheridan, Wyoming
I believe that no load ac voltage was about the same as the 350 dc volts through the filter. My 270 milliamps was the total filament draw, which I now realize is unimportant here! How do you get the actual amps drawn from the tubes? I assume it is in the data sheet, if I would look more closely. I think I am dealing with a total of 69 milliamps current at the plates of the 4 tubes totaled...... William


Top
 Profile  
 
 Post subject: Re: schematic for CLC filtered power supply wanted
PostPosted: Apr Fri 05, 2019 1:43 am 
Member

Joined: Jan Thu 01, 1970 1:00 am
Posts: 7605
Location: Minneapolis, MN USA
Here is a link to the schematic of the radio that the OP wishes to power:
http://www.w7ekb.com/glowbugs/rx/Regens/ACRegenRCA1.JPG


Top
 Profile  
 
 Post subject: Re: schematic for CLC filtered power supply wanted
PostPosted: Apr Fri 05, 2019 2:05 am 
Member
User avatar

Joined: Jul Mon 26, 2010 8:30 pm
Posts: 26565
Location: Annapolis, MD
williampage wrote:
I believe that no load ac voltage was about the same as the 350 dc volts through the filter. My 270 milliamps was the total filament draw, which I now realize is unimportant here! How do you get the actual amps drawn from the tubes? I assume it is in the data sheet, if I would look more closely. I think I am dealing with a total of 69 milliamps current at the plates of the 4 tubes totaled...... William

If that's the case, then the requirement on the DC HV supply is just 69 mA, not 270.

For filaments, your number sounds too LOW....

Back to the HV DC: With no load, the DC output should be close to 1.4 times the rms AC input, If you got 350DC, then the rms AC should be about 250. That means a drop of 10 volts under full load (200mA). That means that the DC resistance of the HV secondary is roughly 50 ohms......plausible for that rating

_________________
-Mark
"Measure voltage, but THINK current." --anon.


Top
 Profile  
 
 Post subject: Re: schematic for CLC filtered power supply wanted
PostPosted: Apr Fri 05, 2019 2:10 am 
Member
User avatar

Joined: Jul Mon 26, 2010 8:30 pm
Posts: 26565
Location: Annapolis, MD
Filaments:

The first 3 tubes are 150mA each. The 12V6 is 225.......Total 675mA

_________________
-Mark
"Measure voltage, but THINK current." --anon.


Top
 Profile  
 
 Post subject: Re: schematic for CLC filtered power supply wanted
PostPosted: Apr Fri 05, 2019 6:56 pm 
Member

Joined: Jan Fri 04, 2019 11:32 pm
Posts: 34
Location: Sheridan, Wyoming
I think I am accidently right on , because I did a lot of checking last night, and things lined up as you suggest. Thanks.....William


Top
 Profile  
 
 Post subject: Re: schematic for CLC filtered power supply wanted
PostPosted: Apr Sun 07, 2019 6:21 pm 
Member
User avatar

Joined: Jan Thu 01, 1970 1:00 am
Posts: 5033
Location: Perrysburg, OH, U.S.A.
williampage wrote:
I used a bridge rectifier with two 82mf electrolytics, with a 5 Hy, 50ma. choke in between the 2 caps.

pixellany wrote:
If that's the case, then the requirement on the DC HV supply is just 69 mA, not 270.

Which means that the choke current rating isn't high enough. IMHO the bare minimum would be 75mA.
John

_________________
“Never attribute to malice that which can be adequately explained by stupidity.”
― R. A. Heinlein


Top
 Profile  
 
 Post subject: Re: schematic for CLC filtered power supply wanted
PostPosted: May Sat 04, 2019 11:53 am 
Member
User avatar

Joined: Dec Sun 25, 2016 5:53 am
Posts: 210
williampage,

PM me if you would be interested in a regulated 250 VDC, 100 mA self-contained, small and lightweight OEM B+ supply , for the postage.
Does not weigh much at all.

I need to "thin the herd" considerably.
Regards, rich

_________________
1970's Avionics Tech, USN Attack Squadron 147, "ARGONAUTS" A-7E A/C


Top
 Profile  
 
 Post subject: Re: schematic for CLC filtered power supply wanted
PostPosted: May Sat 04, 2019 4:57 pm 
Member

Joined: Jan Tue 16, 2007 7:02 am
Posts: 3128
Location: Lexington, KY USA
Dale,

How do you know this is the radio?

http://www.w7ekb.com/glowbugs/rx/Regens/ACRegenRCA1.JPG

I asked about an earlier version's schematic in the other thread; the OP has not yet replied.

The OP has mentioned a 12V6GT tube, not seen in either RCA schematic.

And yes, for either version, the B+ load will be more like 40 to 75mA.

If it is important to use an existing 50mA choke, the value of R11 on the above schematic can be modified to adjust the B+ current. (Output tube cathode resistor. Sets tube's bias, and thus B+ draw.)

If a no-load DC voltage measurement is all we have, the output may possibly be about right when loaded, so changes may not be needed at all. However, the loaded output can be adjusted several ways.

Removing the input filter cap to make a choke input filter will result in much lower DC output voltage. If the reduction is too great, a smaller input filter cap value might be used.

An impedance between the rectifier and the choke will reduce the DC output, as will a lower value bleeder resistor.

Ted


Top
 Profile  
 
 Post subject: Re: schematic for CLC filtered power supply wanted
PostPosted: May Sat 04, 2019 8:21 pm 
Member

Joined: Jan Thu 01, 1970 1:00 am
Posts: 7605
Location: Minneapolis, MN USA
By following this path:

The OP has a post on this ARF page asking about the same power supply design requirements for a schematic he wishes to copy from a web page with ham radio callsign and some regen receivers.

That original post is reply # 6 at this thread:
viewtopic.php?f=12&t=352318&p=2968401#p2968401

The ham radio callsign web page he refers to is:
w7ekb

The web page itself is:
http://www.w7ekb.com/glowbugs/rx/Regens/regens.htm

And the referenced receive is at:
http://www.w7ekb.com/glowbugs/rx/Regens/ACRegenRCA1.JPG


Top
 Profile  
 
 Post subject: Re: schematic for CLC filtered power supply wanted
PostPosted: May Sun 05, 2019 6:32 am 
Member

Joined: Jan Tue 16, 2007 7:02 am
Posts: 3128
Location: Lexington, KY USA
Thanks, Dale!


Top
 Profile  
 
Post New Topic Post Reply  [ 19 posts ] 

All times are UTC [ DST ]


Who is online

Users browsing this forum: No registered users and 3 guests



Search for:
Jump to:  




























Privacy Policy :: Powered by phpBB