Puppeteer

Author Topic: Metro 4Kva gen head 6/1 Metro  (Read 27123 times)

behoof

  • Newbie
  • *
  • Posts: 20
    • View Profile
Metro 4Kva gen head 6/1 Metro
« on: March 04, 2010, 04:01:01 AM »
I've got a Metro 4K ST type gen behind a 6/1 Metro listeroid and I'm wondering if I'm able to get any more power out of this? Reason for asking is when I go to start a small air compressor down down down goes the gen and listeroid, really loading up. I can run lights with barely a flicker and turbo heaters etc, no problem.

I've got it wired at 110/120v using only (1) leg (p1) of the gen right now and everything is grounded and wiring is done as it should be.

I've got the Lister spinning at 610 rpm / gen @ 61.5hz / 120volts unloaded.

As soon as the load hits it's like it dies, this is when the compressor tank is half full I might add. Also like to add that when starting the turbo heater it winds up kinda slowly as if it may not want to get up to speed and start?

I thought I read on here somewhere that you could parallel the 110 on these gensets for more amps but I don't know where I read that???

Anyway, thanks for taking a read of my dilema and hope to hear back, best to you all.

behoof aka skipb

NoSpark

  • Full Member
  • ***
  • Posts: 180
    • View Profile
Re: Metro 4Kva gen head 6/1 Metro
« Reply #1 on: March 04, 2010, 05:41:26 AM »
Welcome Skip!

First thing is, 4k is only 2k per leg. If your compressor is drawing 15 amps or better you're maxing out or overloading that leg(15x120=1800w). If your ST4 has the U1,U4,U3,U2 terminals(labels may me different) tie the U1,U4 together and the U3,U2 terminals together to get the full rated output at 120v. If its center tapped you would have to go in and split the stator windings. Also your 6/1 @ only 610rpm is probably maxed out itself and thats not to mention the governor. Hope I got that right its late :P
Anand Powerline 6/1 ST5

Tijean

  • Full Member
  • ***
  • Posts: 208
    • View Profile
Re: Metro 4Kva gen head 6/1 Metro
« Reply #2 on: March 04, 2010, 03:07:35 PM »
What is the frequency and voltage reading when you have it under the heavy load? For instance, if the frequency is dropping to say 55 hertz, voltage may be down near 105V. Your governor may not be responding as well as it could if the spring is ideal for 650 rpm. and it is getting pulled down under 600. Other problems in linkage may be at play also. Make sure you are taking the loaded leg voltage reading, not the unloaded as there is quite a difference.
Frank

10/1 Jkson, ST5 gen. head

mike90045

  • Mendocino Metro
  • Hero Member
  • *****
  • Posts: 1594
  • Mmmm BBQ
    • View Profile
    • Mikes Solar PV page
Re: Metro 4Kva gen head 6/1 Metro
« Reply #3 on: March 04, 2010, 05:06:15 PM »
1)  you need a compressor unloader, to take the high pressure off the compresser pump for easier starts

2) check your compressor motor for possible re-wire for 220V - and then use 220 off the generator.

3) 110V for a larger compressor is a lot of amps, and start up usually needs even more.

one or more should solve this

behoof

  • Newbie
  • *
  • Posts: 20
    • View Profile
Re: Metro 4Kva gen head 6/1 Metro
« Reply #4 on: March 04, 2010, 05:47:22 PM »
Welcome Skip!

First thing is, 4k is only 2k per leg. If your compressor is drawing 15 amps or better you're maxing out or overloading that leg(15x120=1800w). If your ST4 has the U1,U4,U3,U2 terminals(labels may me different) tie the U1,U4 together and the U3,U2 terminals together to get the full rated output at 120v. If its center tapped you would have to go in and split the stator windings. Also your 6/1 @ only 610rpm is probably maxed out itself and thats not to mention the governor. Hope I got that right its late :P

Thanks for the reply.

How would I know if it is center tapped? (have some knowledge but still learning)

And by combining U1, U4 and U3, U2 terminals is that paralleling the outputs??? I haven't looked at it yet to see how it's marked, will check it this afternoon when I get back home.

Seems if I kick up the rpm's anymore than 610 the Hz goes up quite a bit with it so I tried to compromise... how critical is being at 61 - 62 Hz in all of this?

behoof

  • Newbie
  • *
  • Posts: 20
    • View Profile
Re: Metro 4Kva gen head 6/1 Metro
« Reply #5 on: March 04, 2010, 05:52:57 PM »
What is the frequency and voltage reading when you have it under the heavy load? For instance, if the frequency is dropping to say 55 hertz, voltage may be down near 105V. Your governor may not be responding as well as it could if the spring is ideal for 650 rpm. and it is getting pulled down under 600. Other problems in linkage may be at play also. Make sure you are taking the loaded leg voltage reading, not the unloaded as there is quite a difference.

Hi,

As it comes under heavy load it kind of begins to lug/lag on down and the freq and volts go down proportionally with the rpm.

I did the governor spring mod on it (see Utterpower site) using the origianal spring so the tension would remain the same and I did the linkage spring mod (remove all cotter pins and use light type spring to hold all the levers and bellcranks for no slop) and have noticed that response seems a bit slow but haven't had enough experience with it to be sure that it IS slow.

Reading with a Kill A Watt and DVM on loaded leg for readings.

Thanks

mike90045

  • Mendocino Metro
  • Hero Member
  • *****
  • Posts: 1594
  • Mmmm BBQ
    • View Profile
    • Mikes Solar PV page
Re: Metro 4Kva gen head 6/1 Metro
« Reply #6 on: March 04, 2010, 06:28:14 PM »
+ or - 5 Hz won't hurt anything but your clocks. (slow or fast) Motors and transformers are likely good for + - 10Hz before they complain, but the low voltage will really hurt, they will try to pull more amps, and that's more load = slower RPM's = lower voltage.....

Tijean

  • Full Member
  • ***
  • Posts: 208
    • View Profile
Re: Metro 4Kva gen head 6/1 Metro
« Reply #7 on: March 04, 2010, 07:24:00 PM »
What are the actual figures for rpm and frequency to which it drops! Is it black smoking then? This would give a better indication of whether it is governor related.

Doing the end for end swap on the governor spring adjuster screw and providing pivots removes some excess stack rate issue but it will not compensate if the springs inherent stack rate is too high. I did that mod and it improved things on my 10-1 running at 900 instead of 1000 but I still had too much variation. I used two smaller diameter wire springs in tandem to replace the supplied spring. Dont assume that the spring that came with the unit is correct especially if you drop the rpm from what it may have been designed for.

Somewhere in Georges material is a discussion about adding lead weight to the governor fly balls: this changes the spring stack rate relationship but pretty involved cure. It is a given that there must be some rpm drop to actuate the governor but the geometry of the linkage bell cranks and the spring characteristics can created a different amount of movement of the fuel rack in response to a given rpm change.

It is not very easy to simply explain but if you can visualize a spring 3 inches long that can be opened to mid extension by say 5 pounds and compare it to a twenty inch long spring that will open half way by the same weight, I think you can see that any given weight increase will cause more movement in the longer spring than the shorter spring.The two springs have a different stack rate. Some combinations will give lazy response and lots of droop and others will give hunting or loping.

I dont know of any way other than experimenting  but have done lots of it on various welder generators to get them to respond properly. Replacing with parts that look approximately like the others can give you some nightmares. I think somewhere on this site or the other one, there are pictures showing difference in governor weight for different size listeroid engines.
Frank

10/1 Jkson, ST5 gen. head

NoSpark

  • Full Member
  • ***
  • Posts: 180
    • View Profile
Re: Metro 4Kva gen head 6/1 Metro
« Reply #8 on: March 05, 2010, 12:30:13 AM »
Quote
How would I know if it is center tapped? (have some knowledge but still learning)

And by combining U1, U4 and U3, U2 terminals is that paralleling the outputs???


Yes, parallel is 120v, series is 240. If you have 4 separate terminals or lugs to configure your good, but if its center tapped then the stator wiring u3,u4 are soldered together inside the generator and one wire comes out of those as the neutral and you would have to split that and bring them out as u3 and u4. If your already familiar with utterpower, all of this info is there some where, probably under generator or ST.  If it wasn't for my 240v well pump I would have mine parelleled and I wouldn't have to worry about balancing loads.
Anand Powerline 6/1 ST5

behoof

  • Newbie
  • *
  • Posts: 20
    • View Profile
Re: Metro 4Kva gen head 6/1 Metro
« Reply #9 on: March 05, 2010, 02:34:35 AM »
Hi all and thanks so much for guiding me along with all of your great posts, all are greatly appreciated.

Here are some pics I just took to better allow for what I'm dealing with. Not too sure on weather this is a center tap gen head or not because I guess I just don't understand totally what I'm looking at.

http://www.michigan-horse.org/Lister/Bellcrank-mod.jpg
http://www.michigan-horse.org/Lister/Gov-Mod.jpg
http://www.michigan-horse.org/Lister/Glisten-rectifier.jpg
http://www.michigan-horse.org/Lister/Glisten-rectifier2.jpg
http://www.michigan-horse.org/Lister/Glisten-Metro-box.jpg

I made a wind generator out of a Baldor induction motor by clipping the series connection and adding 3 more leads so I can change from Y1-Y2, D1-D2 to control output in different wind conditions etc.( http://fieldlines.com/story/2007/8/27/51542/1469  http://fieldlines.com/story/2007/8/28/51444/7540 if interested in seeing the conversion)  So I'm not totally lost but this generator has me a bit confused still learning, as I say.

So, I'm wonder if after looking at these pics (I hope they came out online) you can let me know if this is center tapped ??? and if not which wire would go where???

Boy they sure do things different in India, you can't even get the lid off this top box without cutting stuff, not gonna do that until hearing back from you guys.

Thanks for looking and all the help,
skipb
« Last Edit: March 05, 2010, 02:41:20 AM by behoof »

behoof

  • Newbie
  • *
  • Posts: 20
    • View Profile
Re: Metro 4Kva gen head 6/1 Metro
« Reply #10 on: March 05, 2010, 02:37:01 AM »
What are the actual figures for rpm and frequency to which it drops! Is it black smoking then? This would give a better indication of whether it is governor related.

Doing the end for end swap on the governor spring adjuster screw and providing pivots removes some excess stack rate issue but it will not compensate if the springs inherent stack rate is too high. I did that mod and it improved things on my 10-1 running at 900 instead of 1000 but I still had too much variation. I used two smaller diameter wire springs in tandem to replace the supplied spring. Dont assume that the spring that came with the unit is correct especially if you drop the rpm from what it may have been designed for.

Somewhere in Georges material is a discussion about adding lead weight to the governor fly balls: this changes the spring stack rate relationship but pretty involved cure. It is a given that there must be some rpm drop to actuate the governor but the geometry of the linkage bell cranks and the spring characteristics can created a different amount of movement of the fuel rack in response to a given rpm change.

It is not very easy to simply explain but if you can visualize a spring 3 inches long that can be opened to mid extension by say 5 pounds and compare it to a twenty inch long spring that will open half way by the same weight, I think you can see that any given weight increase will cause more movement in the longer spring than the shorter spring.The two springs have a different stack rate. Some combinations will give lazy response and lots of droop and others will give hunting or loping.

I dont know of any way other than experimenting  but have done lots of it on various welder generators to get them to respond properly. Replacing with parts that look approximately like the others can give you some nightmares. I think somewhere on this site or the other one, there are pictures showing difference in governor weight for different size listeroid engines.

It will drop right off the map if I don't shut the load down. I can't see the exhaust when this is happening because it's outside and I'm inside but I'm guessing it's probably pretty black from the sounds of the load.

Also, it just doesn't seem like the governor is keeping up once a load hits... just seems like it starts downhill and keeps going??

NoSpark

  • Full Member
  • ***
  • Posts: 180
    • View Profile
Re: Metro 4Kva gen head 6/1 Metro
« Reply #11 on: March 05, 2010, 03:50:06 AM »
Good job on the PMG.

I was expecting something more typical of ST generators which usually have a flimsy box with a plastic or fiber board with evenly spaced studs sticking up out of the board to configure with straps. The pictures are of the rectifier that makes dc voltage to magnify the field, it looks like there is a terminal block, that's probably where the stator wires go. Its hard to say with those pictures.
Anand Powerline 6/1 ST5

behoof

  • Newbie
  • *
  • Posts: 20
    • View Profile
Re: Metro 4Kva gen head 6/1 Metro
« Reply #12 on: March 05, 2010, 03:57:47 AM »
Good job on the PMG.

I was expecting something more typical of ST generators which usually have a flimsy box with a plastic or fiber board with evenly spaced studs sticking up out of the board to configure with straps. The pictures are of the rectifier that makes dc voltage to magnify the field, it looks like there is a terminal block, that's probably where the stator wires go. Its hard to say with those pictures.

I thought the stator wires were coming up out of the generator to the (what looks like the rectifier) Glisten-rectifier2.jpg , I think shows them coming out of the generator??? the screw block on the far side with the red wires, I think,  is just a juction for the output wires as they actually just cross back over to the output terminal block.

Oh and thanks for the "Good job on the PMG" much appreciated.

I think I would have built this a lot different but I'm no electrical guy... just seems cluttered to me, but what do I know?

Do you think those 4 wires coming out of the gen by the rect are the stator wires ???

ADD ON  >>> I just came in from further checking and pulled the variable resistor and cover off to look inside at the wires going up thru the gen body and noticed on the opposite side on the screen (on the opposite side of the commutator from the variable resistor) is are two pieces that look like bakelite or similar with a mass of diodes mounted between them??? This is a 2 phase / 1800rpm / 4Kva gen it has 4 brushes and I see 5 wires actually coming thru the gen body to the rectifier I took the pics of.

I'm at a loss, with 5 wires coming thru does that mean it's center tapped?


skipb

P.S.  If anyone out there has any idea where I could find a schematic for this it would really be appreciated. I've looked and looked to now avail... TIA
« Last Edit: March 05, 2010, 04:37:00 AM by behoof »

NoSpark

  • Full Member
  • ***
  • Posts: 180
    • View Profile
Re: Metro 4Kva gen head 6/1 Metro
« Reply #13 on: March 05, 2010, 04:39:44 AM »
The rectifier has its own AC source called the Z winding in the stator, that AC is converted to DC by the rectifier and sent to the field/rotor through the slip rings to magnify it. The field/rotor in your ST is an electromagnet where the field in your PMG uses permanent magnets. We're looking for the wires that come out of the stator like you rewired on your PMG for Y and Delta. Hopefully someone familiar with your style gen will chime in. The terminal block may be where we need to look.

Anand Powerline 6/1 ST5

behoof

  • Newbie
  • *
  • Posts: 20
    • View Profile
Re: Metro 4Kva gen head 6/1 Metro
« Reply #14 on: March 05, 2010, 05:01:27 AM »
Thanks NoSpark,

Appreciate your response.

Hope to hear from someone about this. I think I'm having more fun that one guy deserves, ya know? Where can you go and learn so much and have fun too?

Will stand by for more response.  Still can't figure that load (and I mean load) of diodes opposite side of the var - resistor. gotta be some kind of rectifiier wouldn't you think?

Skipb