Motor run caps as power supply filter

coldcathode · 13th October 2009, 02:12 PM

Can anyone tell me what DC voltage a 450V AC motor run cap can run at?

grahamb · 13th October 2009, 02:21 PM

If you multiply the ac voltage by 1.5 you get aprroximate dc value.
in your example 450v ac x 1.5 = 675v dc.

rock4016 · 13th October 2009, 02:32 PM

Conservative would be 630V DC. Motor runs are designed to take a pounding so you'd probably be safe going higher. What's your planned B+?

coldcathode · 13th October 2009, 02:38 PM

The Power Tranny is 1150V Center Tapped @ 350mA.
I have a 35/5uf cap and a 10uF cap.
I think what I am going to do is run the 35/5 cap.
I plan to use parallel 5U4GB's or 5R4GY's with the 5uf as input cap then, 15Hy choke, then the 35uF.

The B+ at the first cap is the only "high" one about 560V RMS peaks up to 700V

coldcathode · 13th October 2009, 02:40 PM

The other Option is to run the 10uF as input cap and parallel the 5/35 after the choke which is where I am leaning now that I look at it.

rock4016 · 13th October 2009, 03:06 PM

What kind of amp are you planning? What output tubes?

coldcathode · 13th October 2009, 03:17 PM

This is a project I have been planning and playing around with for years.
It is kind of "eccentric".
It's Push Pull 829B's triode strapped (4) tubes.

I attached preliminary schematics of the input/driver and output sections.

OPT's have not been aquired yet somewhere in the 8K - 10K to 8 ohm range

This is preliminary with many mods to be tested once built.

rock4016 · 13th October 2009, 03:49 PM

The B+ in your schematics is 450-400. You'd need to use the 15H choke in a LCRC or LCLC to get your voltage close. Also, your PS capacitance is low.

If I were going to build your design, I'd use a pair of Hammond 272JX (or better) for mono blocks. I'd probably start with a 5AR4 recitifer (or damper diodes) CLC filter with 10uF 1.5H 100uF for around 400-440 B+.

DigitalJunkie · 13th October 2009, 06:06 PM

One thought about the 35/5uf cap,if the 5uf section is used as the motor 'start' cap,and the 35uf as the motor 'run' cap,you probably don't want to use the 5uf section. 'Start' caps will likely fail under prolonged use. Stick with 'run' type caps only.

piero7 · 13th October 2009, 06:12 PM

Quote:

Originally Posted by coldcathode

This is a project I have been planning and playing around with for years.
It is kind of "eccentric".
It's Push Pull 829B's triode strapped (4) tubes.

I attached preliminary schematics of the input/driver and output sections.

OPT's have not been aquired yet somewhere in the 8K - 10K to 8 ohm range

This is preliminary with many mods to be tested once built.

Interesting project, will you also post the power supply?

13th October 2009, 02:12 PM	#1
coldcathode diyAudio Member Join Date: Jan 2009	Motor run caps as power supply filter Can anyone tell me what DC voltage a 450V AC motor run cap can run at?

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
AC Motor Power Supply Project	gilid	Analogue Source	30	17th May 2011 08:39 PM
Seperate/Dedicate 12V Power Supply for TT's Motor	mike_junior	Power Supplies	0	26th January 2009 02:31 PM
AC motor power supply	calucci	Analogue Source	21	3rd September 2007 05:36 PM
Why not put filter caps in power supply?	Joshua Layne	Chip Amps	7	31st January 2004 03:50 PM
40x 4,700uF 50V power-supply filter caps for sale	OddOne	Swap Meet	4	17th January 2003 07:37 PM

New To Site?	Need Help?
Register to Participate Search Privacy Statement Contact Us	Frequently Asked Questions Did you forget your password? Mark Forums Read

13th October 2009, 02:21 PM	#2
grahamb diyAudio Member Join Date: Jan 2006 Location: durham	If you multiply the ac voltage by 1.5 you get aprroximate dc value. in your example 450v ac x 1.5 = 675v dc.

13th October 2009, 02:32 PM	#3
rock4016 diyAudio Member Join Date: Aug 2005	Conservative would be 630V DC. Motor runs are designed to take a pounding so you'd probably be safe going higher. What's your planned B+?

13th October 2009, 02:38 PM	#4
coldcathode diyAudio Member Join Date: Jan 2009	The Power Tranny is 1150V Center Tapped @ 350mA. I have a 35/5uf cap and a 10uF cap. I think what I am going to do is run the 35/5 cap. I plan to use parallel 5U4GB's or 5R4GY's with the 5uf as input cap then, 15Hy choke, then the 35uF. The B+ at the first cap is the only "high" one about 560V RMS peaks up to 700V

13th October 2009, 02:40 PM	#5
coldcathode diyAudio Member Join Date: Jan 2009	The other Option is to run the 10uF as input cap and parallel the 5/35 after the choke which is where I am leaning now that I look at it.

13th October 2009, 03:06 PM	#6
rock4016 diyAudio Member Join Date: Aug 2005	What kind of amp are you planning? What output tubes?

13th October 2009, 03:49 PM	#8
rock4016 diyAudio Member Join Date: Aug 2005	The B+ in your schematics is 450-400. You'd need to use the 15H choke in a LCRC or LCLC to get your voltage close. Also, your PS capacitance is low. If I were going to build your design, I'd use a pair of Hammond 272JX (or better) for mono blocks. I'd probably start with a 5AR4 recitifer (or damper diodes) CLC filter with 10uF 1.5H 100uF for around 400-440 B+.

13th October 2009, 06:06 PM	#9
DigitalJunkie diyAudio Member Join Date: Apr 2003 Location: Portland,Oregon Blog Entries: 4	One thought about the 35/5uf cap,if the 5uf section is used as the motor 'start' cap,and the 35uf as the motor 'run' cap,you probably don't want to use the 5uf section. 'Start' caps will likely fail under prolonged use. Stick with 'run' type caps only.

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)