Help on American Monarch transformer

[K5WLF]

I was given a power supply from a Motorola repeater. The transformer is an American Monarch # 502845. B+ in the manual shows to be 1500 volts, but I'd really like to know the manufacturer's specs on the iron. Judging from the lack of clues on the internet, I'm thinking A-M is probably paws up. The label on the iron says Minneapolis, but there's nothing shown on the net for them and a phone number in Cleveland that I found on a listserv is disconnected. Any ideas, help or info appreciated.

Thanks,
ldb

[W7TFO]

ol' Doc Hoyer might know where they went:  Autran@aol.com

[W3RSW]

Well for starters just weigh it.  Lot's of tables on the net and in the literature (older ARRL manuals for weight vs. watts.)

 What did the 1500volts feed, FM service? What was the final(s) tube and then look up what the tube takes for plate current in such service.

[K5WLF]

What did the 1500volts feed, FM service? What was the final(s) tube and then look up what the tube takes for plate current in such service.

Thanks for that tip, Rick. A little further sleuthing in a part of the manual I hadn't been in before yielded a "600W Power Input" table which shows a range of 1300-1700 plate volts with corresponding Ip values of 460-353 mA. Appended to the table was the statement: "Never exceed plate current of 500 mA". All that gives me a decent idea of what I might be able to do with this supply.

Tubes by the way are a pair of 8560As in FM service.

Thanks again,
ldb

[W3RSW]

Great!
 If you haven't already done such and now if you want some fun plot the op. voltage vs. current data on a sheet of semi-log paper, volts on the vertical (linear) scale, millamperes on the horizontal (semi-log) scale.

Connecting the points, you'll see a straight line for most of the recommended operating range.
It's also fun to find the bleeder only voltage and plot that, then take a heavily loaded voltage using a high wattage resistor of, say 1.25 k and plot that.

You'll see immediately that you'll have an "S" curve rising quite high from your 'linear' appearing region on the lightly or no load side and sagging rapidly on the heavily loaded side.  I've done that on a lot of transformers over the years, finding that older, continuous service rated transformers for FM service are fantastic for lighter services such as SSB and great for equivalent AM service.

Note that there's no zero on the semi-log scale of the paper.  I'll leave that as an excercise for the students perusing AMfone.