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Components and Circuits For discussions about component types, alternatives and availability, circuit configurations and modifications etc. Discussions here should be of a general nature and not about specific sets. |
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23rd Mar 2023, 5:00 pm | #1 |
Heptode
Join Date: Jun 2018
Location: Carmarthenshire, Wales, UK.
Posts: 569
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Wax capacitors
I have 3 wax capacitors I want to replace but not sure what to replace with they are:-
0.02uF 750VDC 0.01uF 1000VDC 0.005uF 1000VDC Can any one help with what replacement values and voltage please? Thanks. |
23rd Mar 2023, 5:05 pm | #2 |
Moderator
Join Date: Jan 2003
Location: Ipswich, Suffolk, IP4, UK.
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Re: Wax capacitors
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23rd Mar 2023, 5:07 pm | #3 |
Octode
Join Date: Mar 2020
Location: Blackburn with Darwen, Lancashire, UK.
Posts: 1,573
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Re: Wax capacitors
Without everyone knowing what the application is and where in the circuit they are then one can only suggest the same voltages and values, 0.0047 will probably do for the 0.005 and 0.022 for the 0.02 you have.
CPC have a range of caps over 1000 Volts but no 10nF in stock at the moment. https://cpc.farnell.com/w/c/electron...e=inc-in-stock Perhaps Farnell, RS or even Ebay may be a way forward. Adrian |
23rd Mar 2023, 5:36 pm | #4 |
Dekatron
Join Date: Apr 2019
Location: Worthing, West Sussex, UK.
Posts: 6,604
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Re: Wax capacitors
Any modern good quality type would be suitable generally, I personally prefer Polypropylene Metallized Film, often yellow.
David |
23rd Mar 2023, 5:37 pm | #5 |
Nonode
Join Date: Jun 2013
Location: Surbiton, SW London, UK.
Posts: 2,801
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Re: Wax capacitors
These are probably decoupling, HV ceramics are ideal and cheap;
https://cpc.farnell.com/multicomp-pr...y5p/dp/CA08718
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24th Mar 2023, 12:10 am | #6 |
Nonode
Join Date: Jun 2007
Location: Coulsdon, London, UK.
Posts: 2,171
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Re: Wax capacitors
High voltage waxies were sometimes used across the primary of the output transformer or across the mains.
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24th Mar 2023, 10:01 am | #7 | |
Banned
Join Date: Jan 2023
Location: Neath, Port Talbot, Wales, UK.
Posts: 286
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Re: Wax capacitors
Quote:
They really woke you up. I had one of those go off about 10 years ago. It tripped the RCD on the bench as it went. |
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24th Mar 2023, 10:29 am | #8 |
Hexode
Join Date: Mar 2019
Location: Edinburgh, Scotland, UK.
Posts: 350
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Re: Wax capacitors
When sourcing hard to find parts you can connect eg 2 x 22nF/1000v parts in series for 11nF (bonus is voltage rating doubles). For parallel connection the capacitance doubles, eg 2 x 22nF doubles to 44nF and voltage rating stays at 1000v.
Use an online capacitance series/parallel calculator if using dissimilar capacitances. |
24th Mar 2023, 10:45 am | #9 |
Dekatron
Join Date: Sep 2011
Location: Rugeley, Staffordshire, UK.
Posts: 8,835
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Re: Wax capacitors
Just look for those values of capacitance coupled with voltages the same as or higher at Cricklewood Electronics. I have dealt with them for years; fast, efficient and decent on price, oh and good quality caps.
https://www.cricklewoodelectronics.c...-to-1000V.html The point being, it's generally only when you get down to small pF values that the actual 'spot on' value is important. So, in this instance, 0.022uF is perfectly good for 0.02uF, and 0.0047uF is good for 0.005uF.
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24th Mar 2023, 10:55 am | #10 |
Moderator
Join Date: Mar 2012
Location: Fife, Scotland, UK.
Posts: 22,902
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Re: Wax capacitors
You haven't said what they're for. If they're used in mains filtering, then there are safety concerns. 1000v waxies were once used for these tasks. There are special grades nowadays for these uses.
David
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25th Mar 2023, 11:34 pm | #11 | ||
Nonode
Join Date: May 2007
Location: Redruth, Cornwall, UK.
Posts: 2,580
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Re: Wax capacitors
Quote:
Regards, Symon |
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25th Mar 2023, 11:46 pm | #12 |
Nonode
Join Date: May 2007
Location: Redruth, Cornwall, UK.
Posts: 2,580
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Re: Wax capacitors
I generally use axial lead polypropylene caps as replacements but decent quality polyester film caps are also good. The Mullard mustard caps are also decent parts to use.
For the mains filter cap, a Class X2 type is recommended but a 1000Vdc rated polypropylene type is a good safe alternative. Regards, Symon |
26th Mar 2023, 9:04 am | #13 |
Dekatron
Join Date: Nov 2010
Location: Oxford, UK.
Posts: 4,996
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Re: Wax capacitors
I restored the Lorenz SZ42 cipher machine at Bletchley maybe 15 years ago. It hadn't run since it was captured during the late days of WW2, so it was a red letter day when it started running again.
Then after a few minutes - bang! The drive motor had a CLC filter to stop commutator noise getting onto the power lines, which also fed sensitive receivers. The capacitors had blown. Of course the filter box was pitch filled. Melting that out gave enough information regarding the capacitor values, which I replaced with the correct X2/Y1 grade modern components, then filled back up with pitch. That sorted it! Craig
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