Hi. I have construct this linear 500w rms (2kw pep) (50ohm) with 12 mosfet
irfp360, http://tzitzikas.webs.com/linear500w.jpg
schematic.
The manufacturer and other radio amateurs from a greek forum have construct it
successfylly.
The manufacturer tells that the linear requires only 2 watts r.f driving power
for full 500w output r.f
power. The supply is 70-110vdc and for maximum power with 110vdc tha current is
13A (without am modulation).
Without driving power, we must adjust the current at 200mA (when the linear is
cold).
My problem is this: When i tried to adjust the current at 200mA without driving
power, when the current close to
160mA (by tuning the variable resistance 5Kohm) suddenly the current takes the
value 3A and some smoke comes out
from the input transformer.
some photos from my linear and pll here:
http://www.tzitzikas.webs.com/linear10.JPG
http://www.tzitzikas.webs.com/fet.JPG
http://www.tzitzikas.webs.com/linear11.JPG
http://www.tzitzikas.webs.com/linear12.JPG
http://www.tzitzikas.webs.com/pll10.JPG
http://www.tzitzikas.webs.com/pll11.JPG
http://www.tzitzikas.webs.com/pll12.JPG
http://www.tzitzikas.webs.com/pompos.JPG
With 2w input driving power from my pll and supply at 110vdc, and 150mA current
without input r.f power, the output power was
only 60w and the current was only 3,5A without modulation.
Witch do you think is the problem? Thank you very much and sorry for my English.
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