3kw Hercules ZXB

[KA3EKH]

Although it’s not directly radio related I just put up a You Tube video of my 1940 Hercules ZXB generator at:

https://www.youtube.com/watch?v=VB2Hn6clw6M

It’s a three phase 3 kW flat head four cylinder engine, for reasons that I cannot completely explain I wanted a flat head engine project so this is it. Also has the added bonus of you start it with a crank. It had a starter motor added when I got it so I kept it and demonstrate how it starts easy when warmed up but cannot imagine trying to start it when it’s cold or lost prime.
Although it would be a stretch now have a way to power three phase transmitters at home.

[SM6OID]

Hi!

A very nice generator!
For some weird reason, I also have a kind of fascination for flat head engines.

May I advice you to use another cranking technique, in case it kicks back, you may suffer from quite serious injures.
All fingers, including the thumb on the same side of the handle is probably rule #1.
The next rule can be adjusted depending on the particular engine, but the safest is probably to only "pull upward".

There are many different ways of hand cranking engines, or kicking with the foot for that matter.
So far I have not been hurt badly, other than my pride...
I have engines from 3½-169 hp that I have hand cranked, the latter a Rolls Royce B80, inline 8 (346 CID).

[KA3EKH]

There is just something magically primitive about a flat head engine. The old ZXB has the external side mounted water pump and originally it had a magneto ignition system. When I got it the coil in the magneto was shot so had to add external ignition coil and resistor, perhaps some day may find another magneto and go back to that.
Also like all the brass work on the engine including the all brass carburetor.
Think the ZXB engine was designed for small farm tractors and as such was designed to be easily maintained and intended to run forever. Far cry from many of the items produced today.
Have had at least two people tell me about placement of the thumb and proper procedures for hand cranking now that the video is online.  I will try to keep that in mind for the future.
Think that being able to select items that were in there time the best of technology and keeping that stuff operational today may be the key to a lot of what drives us to restore and collect.  At the end of the day the thing that limits the size of our collections is the amount of floor space that’s available.

[W7TFO]

Years ago I had an American Marc milspec Diesel generator.  2-cyl, rated at 5kW.

I was handcranking it with the compression release open, getting it to really spin.

Fast & faster it went, I really leaned into it.

I had my wife close the release, and I promptly shit my pants...

73DG

[KA3EKH]

Ok, so I have been having an issue with the generator being its voltage regulating system doesn’t work. Understand that frequency control is maintained by the mechanical governor and that’s right on at 60 cycles @ 1800 RPM but the issue is voltage control.
If I run the generator in manual voltage control can use the rheostat on the control panel to control output voltage but when I switch it to automatic the output drops way down to sixty volts.
I have mentioned before that the voltage control is thru some very strange looking device. Discovered today that the “thing “is a Ward Leonard 5660 voltage regulator. Removed its protective cover and inside is two huge multi tap ceramic resistors on each side and something that looks like a relay in the center that has a twisted bar that appears to vary a rolling carbon bar across a dual set of very strange looking coil contacts.
I did clean it all up and also cleaned the high wattage variable resistor in series with it but did not have time to put it all back together and test run it to see if it works.
Did a quick internet search and Ward Leonard is still in business and was a leader in developing motor speed and control systems from back as far as 1890
I am including a picture of this strange looking device in case there is someone out there who can explain how this thing works. And yes I know it varies the field voltage but just how dose it function?

[W7TFO]

Iy works by monitoring the output voltage thru an electromagnet, which moves contacts to either raise or lower the sensed voltage thru altering the field excitation.

It is simpler than it looks, in reality.

I'd pull it (after marking where every connection goes), and perform continuity tests on the bench.

The field circuit should show some value of low resistance, moving in tandem when you slide the contact arm back & forth.  If there are any 'glitches', there is either an open or bad contact.

Trace everything to make sure you are getting a true representation of output voltage at the electromagnet coil as well, and that it is not open.

73DG

[W2PFY]

I am including a picture of this strange looking device in case there is someone out there who can explain how this thing works. And yes I know it varies the field voltage but just how dose it function?

 Are those selenium bridge rectifiers down in the bottom under that spring area?