The AM Forum

 I found this NIB tranny at a local surplus store today. Model #E750  220x440 Primary/110 secondary 50-60HZ rated at .75KVA with 31 pounds of copper and iron.
 http://www.solahd.com/products/transformers/pdfs/iec/sbeencapsulated.pdf
 Would this piece of iron have any use in an AM transmitter(Mod,Heising,Choke,etc)?

                                                                                                                             73
                                                                                                                            Mike

                                                                                                 

the inductance would be quite low for the high voltage, high level modulation circuit. it might be well to consider the conditions it is designed for - -

0.75KVA @ 110V = 6.82 amps, appx 16 ohms load. This is sort of based on the operating parameters, as the unit has enough inductance to support this.

60Hz:
110V =  16 Ohms
220V = 64 ohms
440V = 258 ohms

120Hz: double all the Ohms figures

1200Hz, mult the Ohms by 10. But the iron may not do well at full power up there.

However, the unit might do 60-4000Hz at the same impedance levels as it does at the design frequency of 60Hz, with a reduction in power to about 1/4 to 1/2.

This is based on some experience with using a 120V to 40V/5A power transformer as a cathode modulation transformer and pushing about 50W through it over a range of 40-7000Hz.

your mileage may vary. But keep it out of the plate modulation circuit, it is a low-Z item.

It might be a half decent negative-lead choke, have you checked the inductance on the 440V connection? The issue is it might not stand the peak voltage across it.

Hooked up for 440V, it would make a dandy xfmr for voltage doubling and using tubes in the 1000V class, and the 750W rating is nothing to sneeze at for a small transmitter. If you voltage double, though use a fullwave circuit like the 4x8 so the transformer is fully utilized. might make 850V at 700mA. well we are grasping for straws, the possibilities are endless, only not for the things you are asking.

I usually use things like this around the shop for getting 240 or 480 conveniently to test stuff. There is a 1KVA one on the bench..