Fw: [Boatanchors] rotor starting capacitor

[Peter Markavage]

Actually, depolarizing both capacitors is what I want.  "with attendant
consequences" Have no clue what that phase means. 

Anyway a field note from Cornell Dubilier in 1962, when the were located
in NJ, indicated that identical back to back electrolytic capacitors (+
to + or - to -) at twice the capacitance of the installed motor start
capacitor could be used as a replacement if necessary. DC voltage ratings
of both capacitors must be identical. I believe this was also documented
in one of QST's Hinks and Kinks. 

The TR-4 motor start cap was replaced with back to back electrolytic caps
in 1974. It still running today. The motor start cap in the CD-44 was
replaced with back to back electrolytic caps in 1987/88. It still running
today.

This one works for me.

Pete, WA2CWA

On Wed, 7 Jul 2004 18:51:37 +1000 "Brian Clarke"
<brianclarke01 at optusnet.com.au> writes:
> 
> Sorry, Peter,
> If you wanted a non-polarised or ac rated capacitor, wiring two 
> polarised
> capacitors back-to-back is NOT the same a non-polarised or ac rated
> capacitor.
> What you have done is increase the risk of depolarising BOTH 
> capacitors,
> with
> attendant consequences.
> 73 de Brian, VK2GCE.
> 
> You said:
> I use the real cheap and lazy way to replace these caps. Either 
> rummage
> the junk box for two "regular" electrolytics at double the 
> capacitance or
> pillage them from discarded computer or monitor power supplies and 
> just
> wire them back to back. PC mounted or wire leads makes no difference 
> as
> long as I can get to the leads. No one looks inside my rotor box but 
> me.
> This has always worked for me in all the CDE/CDR rotors I used over 
> the
> years including the CDR TR-4, which I bought in 59, and still turns 
> a TV
> and FM antenna.
> 
> On Tue, 6 Jul 2004 19:15:11 -0700 (PDT) Glen Zook <gzook at yahoo.com>
> writes:
> > As a result of my recent need for a control box for my
> > 45 year old CDE AR-22 (hopefully have one on its way)
> > I discovered a very inexpensive source of a
> > replacement for the starting capacitor that is used in
> > most brands of rotors.
> >
> > The cheapest place that I found these was W. W.
> > Grainger Company.  They have branches in many areas of
> > the country.  However, they no longer sell to
> > individuals.  But, if you have a company, or work for
> > a company and have a business card, they will open you
> > a "cash" account and you are in business.  Also,
> > Grainger has all sorts of other things that you just
> > "can't live without"!
> >
> > Anyway, Grainger part number 4X064 is a 110/125 VAC,
> > 50/60 Hz, 233-280 mfd capacitor that works perfectly
> > in place of the same range in capacitance but 50 VAC
> > capacitor that is used in most rotors.  The price is
> > $4.07 in single quantities.  The capacitor is made by
> > Mallory and their part number is 3534B2A0233A110.
> >
> > I would suspect that the capacitor is available from
> > motor rebuilding shops, etc. under the Mallory part
> > number.  However, the price may be a little bit
> > higher.
> >
> > Since the capacitor is rated at 110/125 VAC they are
> > slightly larger than the original capacitors.  But,
> > they will fit in most control boxes.  Also, they had
> > terminals for "slip on" connectors.  But, I had no
> > problem soldering on wires to make the connections
> > inside the rotor control boxes.
> >
> > Since I was quoted prices up to about $15 for a
> > replacement capacitor, I definitely could solder a
> > couple of short wires to the capacitor and save well
> > over $10!
> >
> > Grainger's web site is
> >
> > http://www.grainger.com/Grainger/wwg/start.shtml
> >
> > and the description of the capacitor can be found by
> > using the "search" function at the top of the page.
> > Just "click" on the arrow next to "keyword(s)", click
> > on "Grainger item number", and then put in 4X064 in
> > the box to the right and click "go".  It will take you
> > right to the item!
> >
> > Anyway, if you are a firm believer in the principles
> > of the conservation of your finances and labor (you
> > can read "cheap and lazy") like me, and if you are in
> > need of a starting capacitor to repair your rotor (the
> > capacitor going bad represents at least 90% of the
> > problems with rotors), then this capacitor is a viable
> > alternative to paying what the rotor manufacturers
> > want!
> >
> > Glen, K9STH

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