Behlman has been the Lexus of variable frequency power sources ever since the 1960s.  The 25-C has a power rating of 250 V-A but are *very* conservatively rated, able to put out 150% of rated load continuously if you can tolerate more harmonic distortion in your load.  The C models are were made in the 1970s and 80's IIRC, eventually replaced by basically the same thing but with more modern power transistors and a digital meter.  I still have a 100-C that has a single 400Hz frequency plug-in, and a 50-C with a 45-2000Hz variable oscillator.  I've used them for twenty years working on my equipment at aafradio.org.   I bought both of them on ebay for parts but found that they were easy to repair.  The 50-C "parts unit" is pictured below, and I primarily use it for the WW2 Navy 800Hz equipment.  I'm partial to the C models because they use an analog voltmeter.  They are modular in design so that with additional power transistor banks they can get up to quite high current outputs.  I have a some spare parts for the C model if you need any.

Mike  KC4TOS

Is anyone familiar with Behlman AC power sources?   There is a Behlman Model 25-C on Facebook marketplace.

I don’t see a manual available for this. Would this be a good 400 Hz power source for WWII avionics?  Looks like the AC output voltage is adjustable.

Gary

WA2OMY