ST head voltage regulator

[Copybell]

I understand from reading this forum, Jeff M. has made a voltage regulator for the ST head.  After searching this and 'the other' forum I cannot find the schematic.  Can someone tell me where to find Jeff's schematic or any other voltage regulator schematic for a do it yourselfer?

COPYBELL

[lev-l-lok]

Copybell, I believe Jeff's schematic is on both the Utterpower site and CD. Good hunting, and happy holidays.
Let us know how it works at smoothing the sine wave. I think several members have used this circuit with some success, hopefully they'll respond.

[adhall]

lev-l-lok,

I'm interested in voltage regulators, too. Thanks for the suggestion, but I've looked all over the Utterpower website for the schematic you mention but haven't been able to find it. Can you point me in the right direction?

Maybe it's just time for me to break down and buy George's CD...

Thanks,
Andy Hall

[lev-l-lok]

Andy, first page of George's site, scroll down to People, Jeff Maier. Taht is, I believe the circuit you are looking for. I seem to recall one other circuit as well, if I can find it, I'll let you know. I'm just now starting to go through the Changfa and the 10kw, so I'll be wanting that info as well.

[mjn]

I too am looking for the schematic for Jeff M's AVR.  I have never seen it on George's site, or on the CD. (my copy of the CD is over a year old, so I may be out of date)

The closest that I have found is http://www.homepower.com/files/mark8.pdf which has a schematic for a regulator for a car alternator.  It might be possible to scale this up to around 50 volts for the ST head, but it is beyond my electronics skills.

[Doug]

All you need to do is beef up Q2, to what ever the St needs for feild current and put a voltage devider between the the line and neutral ( or better still a small transformer ) and recitify the output for sample voltage.

Should work fine with minor mods.

I built a regualtor a little less sophisticated ( under statement ) for the same reasons in 1993 based on a GM SI alternator regualtor for a big Leace neville. The same idea charge rate control.....

Its some place in Malaysia, gave it tot a friend of mine as a teaching aid for his students...

Doug

[mobile_bob]

Doug:

just remember that next time you design and donate something for educational purposes

remember "LIT" 

i hear there are some really good folks over there doing important research

bob g

[Doug]

What do you mean LIT?

I buggered myslef a couple of times having the right idea at the wrong time and lost out to others...

My chum TJ teaches HDEMs and a little electronics. He thought it was cool as hell to build a regulator out of discrete parts and a great way to teach students basic electronics theory. I even stuck it in an old Dleco remy mechanical regualtor box for a generator, with a tiny pot on the side for voltage adjustment.

 

 

[mobile_bob]

ok,,, i nominate Doug as our professor of experimental electronics at "LIT"



professor Doug,,, ya that works

bob g

[mjn]

All you need to do is beef up Q2, to what ever the St needs for feild current...

I woke up this morning to find that I have been accepted as a student in the prestigious Listeroid Institute of Technology.  Personally I was hoping to be ordained into the ministry with the Church of Lister, but I think their standards are higher.

I have even received my first homework assignment from  professor Doug.

Any word on when the midterm tests are scheduled?

[Doug]

Ok L.I.T. now I get it lol....

Uhm... I failed to consider what voltage the field may need. It probably needs to be over 12 volts someone needs to measure the voltage across the slip rings...

Then from there a little rework and new voltage source for Q2. By steeling an Idea from a KB-IC120 I can probably run the electronics at a higher voltage threw a second voltage devider. The LEDs can be dumped they just indicate what parts are actualy working and serve no functional purpose. An SCR crobar might also be a good idea to add so if a failure happens in the elelctronics the crowbar drags the field current and blows a control fuse ( something that should be added after the on switch )

[adhall]

Doug,

The utterpower site says the following about the field voltage on an ST head:

When the head is at 1800 RPMs, the "Z" winding is producing around 53 volts AC. at 2.1 amps, or only 111 watts. This AC is connected to a full wave bridge array of diodes that converts the excitation voltage to DC. At this point you will read 69 volts DC at the output of the diode bridge. these measurements were made with simple FLUKE multi meter and may not represent true voltages or power.

Please note that I was not able to determine which size of ST head this refers to.

Best regards,
Andy Hall

[Andre Blanchard]

Doug,

The utterpower site says the following about the field voltage on an ST head:

When the head is at 1800 RPMs, the "Z" winding is producing around 53 volts AC. at 2.1 amps, or only 111 watts. This AC is connected to a full wave bridge array of diodes that converts the excitation voltage to DC. At this point you will read 69 volts DC at the output of the diode bridge. these measurements were made with simple FLUKE multi meter and may not represent true voltages or power.

Please note that I was not able to determine which size of ST head this refers to.

Best regards,
Andy Hall

I have a 25KW 3ph head with an electronic regulation and the field voltage is right in that 50 to 70 volt range, if I am remembering correctly.

[Doug]

Sounds about right for heads this size....

OK then you need to build a power suply that will provide around 70Vdc and run Q2 from that with....

I don't use CAD (  since vers 9 so I be rusty lol ). Somebody want to step forward and redraw the circut and I'll make the mods and some notes long hand. If time permitts I'll add the crow bar, some propper fusing, protection and notes. I still have wire wraping tool and suplies but I haven't done this in a decade.

Anyone with time and know how wana build a prototype. I don't think I have time.

Doug

[adhall]

You would also have deal with the higher operating voltage.
   --Add a low voltage supply to power the ICs (just a voltage regulator would do). The LM555 has an absolute maximum rating of 18 VDC and the absolute maximum rating for the LM723 is 40 VDC.
   --Re-design the voltage divider that supplies the input to pin 4 on the LM723. This is the voltage that supplies the feedback for the regulator.
   --Make a voltage source for the voltage divider mentioned above which would reflect the AC voltage you are regulating. This means a rectifier and an RC filter.

Best regards,
Andy Hall