Motor run cap failure - Page 4 - diyAudio
Go Back   Home > Forums > Commercial Sector > Vendor Forums > Tubelab

Tubelab Discussion and support of Tubelab products, prototypes and experiments

Reply
 
Thread Tools Search this Thread
Old 7th May 2013, 06:40 PM   #31
diyAudio Member
 
scott17's Avatar
 
Join Date: Aug 2009
Location: JFK
Default Panasonic DMF

I've used many of this type:
DMF Series - Panasonic Electronic Components - Chassis Mount | Dynamic Catalog | DigiKey Corporation

They are oil-filled BTW:
http://www.panasonic.com/industrial/...il-filled.aspx

I included these in a kit that I once offered. Excellent performance. The best feature of all is the cost. Shhhh!

Last edited by scott17; 7th May 2013 at 06:53 PM.
  Reply With Quote
Old 7th May 2013, 08:32 PM   #32
rknize is offline rknize  United States
diyAudio Member
 
rknize's Avatar
 
Join Date: Feb 2009
Location: Chicagoland
Send a message via AIM to rknize Send a message via Yahoo to rknize
Motor run caps can be either electrolytic or film. The latter tend to be more reliable in practice while the former are cheaper.

For this application, you specifically want a film cap. Using a film motor run cap is a cost-effective way to find a high-capacitance film cap.
  Reply With Quote
Old 7th May 2013, 09:34 PM   #33
diyAudio Member
 
Join Date: Aug 2012
Location: Poços de Caldas - Minas Gerais
I really liked the Panasonic DMF, but Digikey asked me $40 to ship + $16 of cost for two peaces.

I found this one (as mentioned in the thread #22), but with different specifications (440V - 40uF). How about installing 2 in parallel? Is enough? or would be much capacitance?.
The final cost of the two + shipping would be around $31.

Many thanks
  Reply With Quote
Old 7th May 2013, 10:21 PM   #34
diyAudio Member
 
scott17's Avatar
 
Join Date: Aug 2009
Location: JFK
Two in parallel would be 80uF. The value of capacitors in parallel are the sum of the values. Multiply the AC rated capacitor voltage by 1.414 to get the DC voltage rating. In this case, 440 x 1.414 = ~622VDC

Quote:
Originally Posted by Sgrilli AD View Post
I really liked the Panasonic DMF, but Digikey asked me $40 to ship + $16 of cost for two peaces.

I found this one (as mentioned in the thread #22), but with different specifications (440V - 40uF). How about installing 2 in parallel? Is enough? or would be much capacitance?.
The final cost of the two + shipping would be around $31.

Many thanks
  Reply With Quote
Old 7th May 2013, 10:51 PM   #35
diyAudio Member
 
boywonder's Avatar
 
Join Date: Jan 2008
Location: So.Cal.
You could also parallel one of these with a 180uf-220uf (or so) electrolytic. That gives you additional capacitance and lower ESR.

There are usually lots of motor run caps available on Ebay, not sure if that helps your shipping $$.
  Reply With Quote
Old 8th May 2013, 01:11 AM   #36
diyAudio Member
 
Join Date: Aug 2012
Location: Poços de Caldas - Minas Gerais
Quote:
Originally Posted by scott17 View Post
Two in parallel would be 80uF. The value of capacitors in parallel are the sum of the values. Multiply the AC rated capacitor voltage by 1.414 to get the DC voltage rating. In this case, 440 x 1.414 = ~622VDC
I´m not sure if VDC is an issue. How much VDC is the target (minimum and maximum)?

Thanks again.
  Reply With Quote
Old 8th May 2013, 01:59 AM   #37
diyAudio Member
 
boywonder's Avatar
 
Join Date: Jan 2008
Location: So.Cal.
Quote:
Originally Posted by Sgrilli AD View Post
I´m not sure if VDC is an issue. How much VDC is the target (minimum and maximum)?

Thanks again.
For an SSE running electrolytics in the PS, 500V is pretty much the max for readily available electrolytic capacitors. Many motor run caps are rated for 370 VAC, and 370 x sqrt2=522VDC so these will also work fine. That would easily handle KT88 B+ voltages.
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
motor run cap question Doug R Tubes / Valves 3 26th October 2012 09:58 AM
CBB65 Chinese motor run cap? PreSapian Parts 0 11th January 2012 05:34 PM
Is this motor run cap suitable for SSE? Horsebox Tubelab 11 2nd November 2011 03:03 PM
Eyuda Motor Run Cap?? neonthecat Tubelab 3 5th May 2011 01:38 PM
Source for 100uf motor run cap. audiobliss Tubes / Valves 3 31st July 2008 03:15 AM


New To Site? Need Help?

All times are GMT. The time now is 02:48 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright ©1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2