St5 schematic?

[d34]

I opened up the st5 cover today to see a board with u1-u6. After thinking about it I figured the 5 & 6 were attached to the connections inside and may give me 60v. I started it up and did some testing (I should have took notes). I never read 60v anywhere. I did get about 25 one way and 90 another way. Can anyone tell me what the u5 and u6 are connected to?

[d34]

I think I may have the reason for the odd readings. The gen head is still setup for 120/240. Which means u3 and u4 are still connected. If this is the case I may be able to get 60v out of it without opening it up. And if I'm correct I should be able to have 60/120 out of it instead of 120/240.

[d34]

I went back to my storage and disconnected u3 and u4. Ohm readings from u1 to u3 is .8 ohms. From u1 to u5 is .8 ohms. From u3 to u5 is .4 ohms.

[Ronmar]

Sounds like you have a 50 OR 60 HZ head.  Remember these things are shipped to a worldwide market.  A 60 HZ only head just has U1-U4.  Because the voltage output of an ST head is dependent on RPM, when you reduce RPM to get down to 50HZ, you also get a voltage drop.  The U5 and U6 tap into an extended winding(longer winding=more votage) to get back up to rated voltage at the lower 50HZ RPM. 

I believe U1 to U3 is one 120V@60HZ winding, while U1-U5 is a 120V@50HZ winding.  U2-U4 is the other 120V@60 HZ winding while U2-U6 is the second 120V@50HZ winding.  For 240V operation @ 60HZ, you tie U3 to U4 and U1 and U2 are your hot leads for 240V.  A neutral lead would be connected to the U3-U4 junction to provide 120V operation in a typical US domestic power panel.  You don't use U5 or U6 unless you want to run at 50HZ.]

The individual stator pole windings are spliced together down in the end of the main generator case near the brushes if you need 60V for some reason...  Here is adiagram from over at Utterpower.com.  It shows the terminal labels, but dosn't show the actual wires going down to an extended U5 or U6 winding...
http://www.utterpower.com/516/figure1/     

[d34]

thanx for bursting my bubble ronmar  ... j/k i really do appreciate it... while thinkin about this i did come up with other ideas tho... how much does it cost to (build or buy) rectify for charging from 60vac as has been talked about on other threads?  the reason i asked is that i have my house setup to run on 120v with no 240v loads... so i can set the head up for 60/120 and have 2 rectifiers (1 on each 60v leg) to produce the dc into my mx60... then i can still have 120v if needed without making any changes...  if this would work correctly i think it would be my best option and make it worth the changes to the gen head...

[Tom Reed]

Doing that will unbalance the generator, unless you are planning to run both at the same time. And your dc to the mx60 will have a lot of ripple in it. A better solution, and one I'm also thinking about, is to use a 4 pole switch to choose 60vdc or 120/240vac. The 6/1 roid I'm running will only make about 50 amps anyway so it will be just about right for the mx60 I have too.

[d34]

what im thinking will not unbalance the generator... 4 pole generator: parrallel 2 poles and the other 2, then those in series will have 120v... i wish i had a way to draw this for everyone to see...  you would have to use 2 rectifiers and it would stay balanced, but the plus to it is you will have 120v all the time...

[bschwartz]

Do a search for BS-ST I think that may shed some light.

[wrightkiller]

   

[bschwartz]

But wait..... there is more to this picture.....

Ideally U1-U5 would be 1 wire wound around 2 opposite poles. This was not the case on my ST-5.  I understand that these were originally designed as a 240v only head.  In order to make them 120v, they simply cut the 1 continuous winding in the middle.  This makes the 2 windings each of which is around 2 poles 90 degrees apart (next to each other).  This is where the head imbalance with odd loads comes in.  I had to go into the head and split the windings, bring them outside the head and then regroup them to have each pair 180 degrees apart.  Two advantages were that uneven loads didn't cause anywhere near the groaning, and I now had 4 windings that could be wired as: 1-240v, or 2-120v, or 4-60v, or 1-120v and 2-60v etc.

It's early, and I'm just having coffee now...... does any of this make sense?

[d34]

But wait..... there is more to this picture.....

Ideally U1-U5 would be 1 wire wound around 2 opposite poles. This was not the case on my ST-5.  I understand that these were originally designed as a 240v only head.  In order to make them 120v, they simply cut the 1 continuous winding in the middle.  This makes the 2 windings each of which is around 2 poles 90 degrees apart (next to each other).  This is where the head imbalance with odd loads comes in.  I had to go into the head and split the windings, bring them outside the head and then regroup them to have each pair 180 degrees apart.  Two advantages were that uneven loads didn't cause anywhere near the groaning, and I now had 4 windings that could be wired as: 1-240v, or 2-120v, or 4-60v, or 1-120v and 2-60v etc.

It's early, and I'm just having coffee now...... does any of this make sense?

thats basically what im wanting to do... i was just hoping the u5 and u6 were already wired that way and they are not... so i need to go in and do the changes inside, then i can have 2-60v leads that i can rectify (2 separate rectifiers) and still have 120v...

[Tom Reed]

I wonder what the wave form of 120vac would look like wired 180 out of phase, instead of 90? Did this affect flicker???

[bschwartz]

Nope. No change to the flicker.  That is caused by the speeding up and slowing down of engines power pulses.  The only change I noticed was what seemed like quieter "happier" running during unbalanced loads.

[Ronmar]

Single phase rectified 60V is going to be really rough...  Will the inverter even accept it?