Re: mot transformer ballasting (fwd)

["Tesla list" <tesla@xxxxxxxxxx>]

---------- Forwarded message ----------
Date: Tue, 18 Sep 2007 07:01:11 -0700
From: Jim Lux <jimlux@xxxxxxxxxxxxx>
To: Tesla list <tesla@xxxxxxxxxx>
Subject: Re: mot transformer ballasting (fwd)

Tesla list wrote:
> ---------- Forwarded message ----------
> Date: Mon, 17 Sep 2007 22:20:00 -0700
> From: Clive Hansen <mrclivehansen@xxxxxxxxx>
> To: tesla@xxxxxxxxxx
> Subject: mot transformer ballasting
> 
> Hello,
>     I am new to coiling and I was thinking of using four mots in series to
> drive my coil. A friend of mine told me this would need to be under oil and
> current limited. I want to go with an inductive ballast and am operating on
> a 15 amp circuit. Any information about how to construct the ballast or what
> kind of oil to use would be appreciated.
> 

For oil, a lot of things will work, but the best all around thing is 
transformer oil.  Typically, you'll have to order it from a oil jobber 
in a 5 gallon pail, and it will be about $6-7/gallon.  Shell Diala AX is 
what I use, but there are ExxonMobil and Castrol equivalents (Univolt 65 
for ExxonMobil).

For smaller quantities, you can use USP White Mineral Oil, often 
available in gallons from feed stores (it's used as a laxative for 
horses, cows, and other livestock).  Drug stores sell it too, but in 
pint or quart bottles, and it gets expensive fast. Mineral Oil also 
doesn't have any controls on the amount of water in it, and dissolved 
water in the oil greatly reduces the insulating properties.

You could also use a non-detergent straightweight motor oil (lowest SAE 
viscosity you can get.. you don't want thick).. The problem here is the 
various additives which might cause problems with the insulating power.

Hydraulic fluid (not brake fluid!) is another possibility.