On May 26, 10:00*pm, Gunner Asch wrote:
On Tue, 26 May 2009 21:14:32 -0700 (PDT), KD7HB
wrote:



On May 26, 5:18*pm, "Lloyd E. Sponenburgh"
lloydspinsidemindspring.com wrote:
Gunner Asch fired this volley :

How about a 480 step DOWN transformer and simply turn it around
backwards?

Due to core losses, copper losses, et. al., it won't work at the 2:1
ratio in reverse.

LLoyd

Hi, Lloyd.
The voltage ratios have to be the same, either direction, as they are
physical quantities(turns counts). What doesn't work it the KVA
rating, according to the electrician that installed the transformer to
operate our convection oven for soldering circuit boards. He said to
de-rate the KVA 10%. We have been running a transformer backwards to
get 480 from 208 for about 4 years, now. 24/7.

Paul

Ayup. I always calculate -20%

Gunner


If a step down transformer is used in reverse, how would one ground
the secondary (which now acts as primary)?