On The Wrong Side Of The Law; Ohms Law that Is.....
Long ago and, in a different place, a RF appliance builder got on the phone and called the Peter W. Dahl Company in El Paso, Texas. This builder needed a Plate transformer to supply B+ voltage. On the other end of the phone, was an Engineer who inquired about the purpose of the transformer in need. The builder spoke to Gary M. and told him that he needed to supply 3300+ volts @ 3.0 amps CCS to power six Eimac 3-500Z Vacuum Tubes in a converted Heath SB-220. He requested a low tap for 2600 volts for CW / Tune mode and, a split primary for 117 vac /234 vac input. The PWD company had an outboard SB-220 X2 transformer design that would do the job.
He order and paid for the transformer and waited for it's arrival; the transformer arrived in about 6 weeks and was connected to the RF appliance where, it proceeded to exceed all expectations delivering a minimum input power of 12,000 VA of energy to the tubes; the appliance operated at a rate of 63% efficiency and delivered the appropriate amounts of watts to a 50 ohm load.
Years later, it was pulled from a closet and offered for sale, I received this in response:
Quote:
Originally Posted by W*TJA
Hi, Your ad for the power supply says 2600v at 3.5amps CCS. The transformer has a secondary of only 975 to 1125v. When you triple the ac voltage to 2600v you have reduced the rating of the transformer to one third or about 1.2 amps. So in reality the power supply is rated at 2600v at 1.2 amps. FYI 73, W*TJA
At that point, I went to look in the bathroom mirror to see if my head was still in the right place or, had it inadvertently slid from between my shoulders and wedged itself up and in between my buttocks; either that, or it seems that my Advanced Class associate has the current requirements to supply the primary (117 volts versus 234 volts) mixed up with the secondary output capabilities under load.
If a "customer" custom orders a item for a specific application, receives such item, uses such item and, the item performs as advertised and described, why is there always someone from the QRZ peanut gallery willing to argue with you about the correctness of 2 + 2 equaling 4?
You are probably wondering, why this wasn't posted somewhere else like over there or in the De-Con Zone here; It posted it in a public place so that my associates with some degree of technical experience can comment: the output of the secondary is rectified by a full-wave voltage doubler circuit (input X 2.828 = output @ 3.5 amps). The unloaded voltage of the B+ supply exceeds 4,000 volts.
Times have changed since the FCC was still handing out Advanced calls in the 4 land area and, I'm on the wrong side of Ohm's Law, or not.
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