[Boatanchors] Sola Constant Voltage Transformers

[Richard Knoppow]

----- Original Message ----- 
From: "David C. Hallam" <dhallam at knology.net>
To: "Boatanchors-qth" <boatanchors at mailman.qth.net>
Sent: Thursday, February 21, 2013 4:50 AM
Subject: [Boatanchors] Sola Constant Voltage Transformers


Does anyone have information about how much current a Sola 
constant
voltage transformer draws with no load? I have had several 
in the past
and noticed they run quite hot even with no load and 
generally hum
rather loudly. I picked up a small one, 250VA, at a ham fest 
and like my
previous experience it runs hot although it doesn't hum. I 
suppose I
could put an ammeter on it and measure, but thought there 
might be some
information some where about it.

David
KW4DH

     I tested one with a metered GR Variac.  With no load 
they draw nearly the full rated current from the line. They 
may actually draw less when there is some load. The ones I 
have all have warnings stamped on them to avoid touching 
because of heat. Some are also rather noisy and "sing". 
While some produce copious power line harmonics the later 
ones do not.  They are good regulators and very good filters 
for junk on the power line. Also, a short on the load side 
shuts them down so they are good protection for at least the 
line and probably the equipment. For some purposes there is 
nothing better but they are NOT efficient.


--
Richard Knoppow
Los Angeles
WB6KBL
dickburk at ix.netcom.com