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Re: Which oils..Capacitor oils
From: Thomas McGahee[SMTP:tom_mcgahee-at-sigmais-dot-com]
Sent: Thursday, November 27, 1997 1:47 PM
To: Tesla List
Subject: Re: Which oils..Capacitor oils
From: Matthew Mills[SMTP:megavolt-at-usa-dot-net]
Reply To: megavolt-at-usa-dot-net
Sent: Wednesday, November 26, 1997 1:24 PM
To: Tesla List
Subject: Which oils..Capacitor oils
Hi, (again)
Im wanting to know what oil to use (Im in New Zealand not America) I
have contacted Mobil and Shell (Shell havent got back to me yet) Mobil
carry Mobilect 34 and 35 which are bothe the same transformer oils
except one has an inhibitor added.
Mobil aslo have Whiterex mineral oil which is USP and BP standards
exceeeding.
There are 3 types which differ by their viscosity.
at 20°C one is 24.2cST viscosity another is 124 and the other is 250
What do I use?
Is this Whiterex the equivalent of USP mineral oil?
Thanks in advance,
Matt.
----------
Matt,
If at all possible use a true transformer oil. Skip the inhibitor.
That is for use in an open environment, and has additives to reduce
oxidation. Of course, if that is all you could get, then it
would be more than OK. In general go for what has the least
additives.
Whiterex is a basic mineral oil. It has a much higher viscosity
than transformer oil, and therin lies the problem. The more
viscous the oil is the harder it is to remove bubbles. The tradeoff
is that a more viscous oil of the same family will tend to have a
higher breakdown voltage (which is a plus). However, all things
considered a true transformer oil is better than mineral oil
because it is better at bubble removal and has a much lower
water content. The water content tends to increase conductivity
and lower breakdown voltage.
Mineral oils not sold as transformer oils are not as highly
refined, and have much higher water content. They can be used
to make capacitors, but you are best off with a true transformer
oil. I figure if the utility company uses it, it must be OK.
Hope this helps.
Fr. Tom McGahee