Bus Conversions dot Com Bulletin Board
November 26, 2014, 03:06:29 PM *
Welcome, Guest. Please login or register.

Login with username, password and session length
News: If you had an Online Subscription: It will not get torn up or crushed if you back over it with your bus.
   Home   Help Forum Rules Search Calendar Login Register BCM Home Page Contact BCM  
Pages: 1 2 3 [All]   Go Down
  Print  
Author Topic: Homebuilt genset...  (Read 6762 times)
gumpy
Some Assembly Required
Hero Member
*****
Offline Offline

Posts: 3318


Slightly modified 1982 MC9


WWW

Ignore
« on: January 23, 2008, 08:38:16 PM »

Ok. I've had a Thermoking engine and genset head for a few years with the intention of building my own genset. I've never taken the time to do this. Maybe this spring.

So, a couple questions. 

1. Does anyone know where I can source pulleys for the set? I will need tripple groove sets in a specific ratio, something like 2100 RPM on the engine, and 3600 RPM on the head.

2. Does anyone know who else has built their own generator and do you have contact information?  I know I've seen a few who did this, but Greg Bush is the only name I can remember. Does anyone have contact info for Greg?

craig
Logged

Craig Shepard
Located in Minnesquito

http://bus.gumpydog.com - "Some Assembly Required"
Paladin
Dave Knight
Hero Member
*****
Offline Offline

Posts: 711





Ignore
« Reply #1 on: January 23, 2008, 09:06:44 PM »

I have some links on the subject, someone who was also making the pulleys on a special order basis. I found a place that sold pulleys for go carts and such but can't find the link at the moment.  I was thinking of going with direct connection via couplers.
I'm trying to locate all of the info but here is part of what I have:

http://www.mikeholt.com/forum/Forum1/HTML/002287.html

http://www.geoduck.com/epicenter/order.cgi?page=power_sources_generators_and_batteries.html&cart_id=%%cart_id%%

« Last Edit: January 23, 2008, 09:08:20 PM by Paladin » Logged

'75 MC-8   'Event Horizon'
8V71  HT740
Salt Lake City, Utah

"Have bus will travel read the card of the man, a Knight without armor in a savage land...."
TomCat
It's 4:20 somewhere...
Sr. Member
****
Offline Offline

Posts: 411



WWW

Ignore
« Reply #2 on: January 23, 2008, 09:09:39 PM »

Craig,

You may find what you need starting on page 1026 at www.McMaster.com

Jay
87 SaftLiner
Logged

On The High Plains of Colorado
TomC
Hero Member
*****
Offline Offline

Posts: 6901





Ignore
« Reply #3 on: January 24, 2008, 12:11:39 AM »

Grainger has pulleys too.  Would suggest running the engine at 1800-will be quieter.  Then a simple 1:2 ratio will be needed.  Good Luck, TomC
Logged

Tom & Donna Christman. '77 AMGeneral 10240B; 8V-71TATAIC V730.
Paul
Full Member
***
Offline Offline

Posts: 136


Will it ever be done?


WWW

Ignore
« Reply #4 on: January 24, 2008, 02:33:26 AM »

Try Browning Mfg in Maysville, Kentucky.  They will have a distributor in your area. browning is part of the Emerson Power Transmission.  www.emerson-ept.com   There is a lot of help on this site. Use their locator to find a distributor close.

     Paul
     www.incredibus.com
Logged

Paul
http://www.incredibus.com
1988 MCI 102A3 /8V92 /740 /10" Roof Raise
rv_safetyman
Hero Member
*****
Offline Offline

Posts: 2199


Jim Shepherd


WWW

Ignore
« Reply #5 on: January 24, 2008, 04:59:40 AM »

Hi Craig.

One of the better sources for both the belts and pulleys is:  https://www.motionindustries.com.  They will have more than one branch in your area. 

You will want to use what the industry calls "narrow" industrial belts (3V/3VX).  That product line does not have as many belt sizes as the "classical" industrial belts (B/BX), but they have higher ratings and are made of more heat resistant material.  When you get closer to putting the package together, drop me a note and I will help you design the drive (balance the sheave combination with belt length to get the center distance you want, plus make sure you have enough capacity).  If you choose to work directly with a vendor to design the drive (not many offer that service any more), do not get too concerned about the published belt ratings (they are based on 25K hours ratings). 

Going with 3V/3VX belts will mean that you will be using pulleys that are mounted on the shaft with tapered bushings (two different systems) and that is a good thing. 

Also, you will need a speed control system that will assure controlled 60 HZ power. 

Bob Belter (same name in the member list) has done almost exactly what you are doing.  He used a belt driven head and a VW diesel engine.  Just looked at it this past week at the Eagle Rally.  He can tell you what controller he used.  He also has made a very quiet enclosure that sandwiches plywood/lead sheet/roof felt.

One last consideration, be sure that the head is capable of having the radial shaft load that will be created by the belt drive.  Some are only designed to be direct driven.  I suspect the engine you have will not have the same issue.  Many of those units used belt drives and the rear main was designed to handle the radial loads.

Jim
Logged

Jim Shepherd
Evergreen, CO
’85 Eagle 10/Series 60/Eaton AutoShift 10 speed transmission
Somewhere between a tin tent and a finished product
Bus Project details: http://beltguy.com/Bus_Project/busproject.htm
Blog:  http://rvsafetyman.blogspot.com/
NCbob
Hero Member
*****
Offline Offline

Posts: 1261


"Foolish Pleasure" 35' MC5A




Ignore
« Reply #6 on: January 24, 2008, 05:47:26 AM »

Craig, it would be helpful to know if the engine was governed at a specific speed to run the compressor in it's original configuration.  My guess would be that the Engineers would have designed the package so that the engine ran at it's best torque/horsepower curve.  This would be an ideal point to work from and select your pulleys accordingly. Something tells me that you've already done that since you refer to the 2100 RPM point.

My other concern is the HP of the engine.  It takes 1.36 HP to create 1 KW of power. If these numbers fall in line with your numbers...you're in.

Another factor which would concern me would be the droop factor of the existing governor. That would determine the engine's ability to absorb applied loads and recover to governed speed without too much delay. Normally we would not switch off each load circuit before switching to 'Generator'...we'd just flip the switch and hope the genset could absorb the load. That's where the governor droop and acceleration rate of the engine come into play.

Guess I've given you enough ideas to think about. I have no doubt that when you finish you'll have exactly what you want.

Bob
Logged

True friends are difficult to find, hard to leave and impossible to forget.
Kristinsgrandpa
Sr. Member
****
Offline Offline

Posts: 426


1988 Neoplan AN 340, 6V-92 TA DDEC II, HT 748 ATEC




Ignore
« Reply #7 on: January 24, 2008, 10:15:23 AM »

   Craig, my brother built a genset from an Isuzu C-201 Thermo King  engine and a 10 KW head. He might be able to help you some.

He used double belt pulleys, but a triple would be better.

He has no problems with HZ/RPM without a controller. Maybe the governor is that precise, I don't know. I believe he set the speed at 60.5 HZ, no load, and with everything in the coach running it stays on 60HZ. 
My brothers is set up for 1400 RPM but that is too low, mine runs at 1800 RPM with a 15 KW head with no problem at all.  So I agree with Tom C, 1800 RPM is about right.

Boogiethecat has a good source  for votage regulators.  He will probably chime in here with some info.

 I have the name, address and model no. written down somewhere if he doesn't pop in on this. Its very reasonably priced.

I have a Thermo King with a C 201 also, but it is direct drive with an Ohno head on it. I got mine from a man in Arthur, Il that runs a generator build/rebuild shop. If you have any trouble with the Thermo-king he can help tremendously.

He copied his manual and sent me a copy.  My brother also has a different manual (a better one) that he copied for me. 

The man in IL, Lloyd Dean, told me that he has seen C-201 engines go over 100,000 hours with just occasional rings and bearings replaced. They have tungsten carbide cylinder sleeves.

I'll have my brother contact you if you want, and can also give you Lloyd Deans phone no.

Ed.
« Last Edit: January 24, 2008, 10:24:05 AM by Kristinsgrandpa » Logged

location: South central Ohio

I'm very conservative, " I started life with nothing and still have most of it left".
gumpy
Some Assembly Required
Hero Member
*****
Offline Offline

Posts: 3318


Slightly modified 1982 MC9


WWW

Ignore
« Reply #8 on: January 24, 2008, 10:59:07 AM »

Ed,

Yes, please have your brother email me his contact info and Lloyd Dean's info, also.

This sounds exactly like what i'm going to do. That's the engine I have. I talked to Greg Bush this morning about his. He used a 3 belt pulley system on his. I'll probably do that.

Greg said his governor was just fine. Maintains frequency well.

I was thinking I had read something that said the engine was set up for 2100, but that may not be the case. 1800 is probably correct. That's what Greg set his at, too. It's been a while since I looked at this stuff. I have redesigned the Thermoking reefer starting system so that I should be able to start it with a single switch, or have my inverter start it. I think I'll try to build that this winter and get it ready.

craig

Logged

Craig Shepard
Located in Minnesquito

http://bus.gumpydog.com - "Some Assembly Required"
gus
Hero Member
*****
Offline Offline

Posts: 3542





Ignore
« Reply #9 on: January 24, 2008, 01:28:37 PM »

Craig,


For best engine efficiency try to set your engine speed at the max torque speed and adjust the gen required rpms with your pulleys.

You may not have enough HP at max torque speed but this is best if you do. You can easily find out by using the HP/torque curves available for most engines.
Logged

PD4107-152
PD4104-1274
Ash Flat, AR
Bob Belter
Full Member
***
Offline Offline

Posts: 148


Eagle 01 //Cummins M-11 Roadranger OD RTO1110




Ignore
« Reply #10 on: January 24, 2008, 08:57:23 PM »

Ahoy, Bus Folk,

Yah, I did a genset creation based on a VW engine and a 12KW dynamo.

I got the Gillette dynamo almost 20 years ago.    I got the VW diesel engine about the same time.  Back then, there were few good gensets in the market, and a 12KW unit would about take up a complete bed of a pickup truck.
The Gillette dynamo was 12KW 120/240 VAC – two pole 3600 RPM.  The VW diesel was quiet and of low weight.  My package is quite compact.

Belt drive for the dynamo.  There are excellent comments above for the belt drive pulleys and belts.  In my case, the diesel engine runs about 2100 RPM.

The governor system for the genset is a Woodward electronic device.  A model 4500 controller @ $ 225.00, plus an actuator @ $170.00.  Berge’s Generator Service   310  830 4592 .  Good outfit, and the unit is about good enough to run an electric clock.

Box for the genset is composed of a layer of ˝” birch plywood, two layers of ordinary roofer’s 30# felt, one layer of 2 lb/sq/ft roofer’s lead, two layers of roofer’s felt, and finally, one layer of ˝” birch plywood.  Labyrinths for air flow in and out. 

Mufflers are two cheap Kragen 1 1/2” units , plus a glass pack return.  Exhaust is out the top.  Working OK with about 175 hrs, and not carboned-up.  Cheap and easy to replace if they clog.

I had planned to include some sound absorbent material inside the box, but it is so quiet as-is, that if anyone else is running a genset, you cannot hear mine.

BTW, Gillette is still in business, and the present dynamos are double wound, so that you can draw 80 % of your load off one phase.  Superb stuff, and eliminates a lot of concern about “balanced loads”.  They must cost about six-bits more than the other dynamos, because none of the bus conversion purveyors of gensets offer them.     

All in all, quite successful.

Enjoy  /s/  Bob
Logged
dparker
Newbie
*
Offline Offline

Posts: 46


mc 7 in progress


WWW

Ignore
« Reply #11 on: January 25, 2008, 07:11:09 PM »

all,

FWIW - diesel engines are typically metered fuel device (ie injector pumps, metered gear pump) or cam valved to the injector in the case of the 2 stroke dd -- these provides for fairly exact speed control especially in constant speed/load applications.  For most genset this is adequate -- you can have 30 RPM's of deviation before it even makes one Hz difference ... (60 hz x 30 = 1800 rpms) this does not matter to most things in coach who really cares if your blower motor runs at 1800 RPMs or 1770 (59 hz), resistive loads (heating elements) are not affected and power supplies don't care as they are looking to just smooth out the oscillations and make dc anyway ... the woodward control is nice unit and is common on gensets of all sizes -- more sophisticated governors utilize PMG control which is a permanent magnet excitation which is tied electronically to the injector pump to allow the genset to more quickly accept and shed load based on changing current conditions (load which requires more or less fuel to maintain the same speed/frequency) to provide a more stable rotation = frequency control under changing conditions --  the more rotational mass you have which is nearly proportional to the KW capacity the less the speed/frequency of the genset will change --- what gets really tough is large gaseous fuel genset 400KW+ that use natural gas or propane since the fuel is not metered -- frequency control is tough when the system is not steady state -- woodward makes these and they work pretty well -- so a woodward for a diesel is easy -- the point to all this run on is ... if you have a genset that is 15 KW and your largest load that can change is 3.5 KW heater then mechanical controlled governor that came on the genset will probably be more than adequate -- but if you are using a 5K genset on motor that pulls 2.5 KW running (more than is recommended but will work) then pmg controlled regulation will increase the response time and better maintain frequency...

good luck -- sounds like a neat project -- i know that you document it well -- i have couple of the units that are placed on the container dollies to provide power to refrigerated containers but they are 480 volt 3 phase -- but like someone indicated those little diesel engines seem to run forever --

i bought a 20 kw genset on a slide -- i wished i would have spent the extra dollars and remote the radiator -- i would have baffled the genset compartment to change the small amount air to prevent residual heat buildup (like on inboard motor boat) since most of the heat would pass out of the radiator in different location-- in this way the genset would be as quite outside the bus as in -- we provide generators (big ones 250 KW+) for concerts, tv productions. etc these units are baffled in this manner (even though they pass the same air through the unit that is used for radiator cooling) i would then have the genset radiator changing air from the exterior of the bus in the back engine compartment above the muffler -- you might even do two fans electric and reverse the flow in the winter time to maintain some heat in the bus engine compartment ...

btw ... when i am at these events i am amazed at how loud the diesel gensets on those high $ prevost entertainer coaches are to the exterior -- they are quite inside but loud on the exterior -- you would think that if are spending 800K + that you would spend 2K more to make the genset quite on the exterior

d-
Logged

1972 MC7

Parker Systems, LLC
800 8 PARKER
rv_safetyman
Hero Member
*****
Offline Offline

Posts: 2199


Jim Shepherd


WWW

Ignore
« Reply #12 on: January 29, 2008, 07:46:51 PM »

Craig, I was messing with my photos from Quartzsite and saw that I had taken a photo of Bob Belter's generator installation.

Jim
Logged

Jim Shepherd
Evergreen, CO
’85 Eagle 10/Series 60/Eaton AutoShift 10 speed transmission
Somewhere between a tin tent and a finished product
Bus Project details: http://beltguy.com/Bus_Project/busproject.htm
Blog:  http://rvsafetyman.blogspot.com/
gumpy
Some Assembly Required
Hero Member
*****
Offline Offline

Posts: 3318


Slightly modified 1982 MC9


WWW

Ignore
« Reply #13 on: January 29, 2008, 07:57:47 PM »

Yeah, I wish I could see one in person.

I've got a line on a local company that might be able to help me with the pulleys.
I'm working on the starting circuitry design now, and hope to start wiring that up this weekend. I thought it was
going to warm up here, but it turned around again, so won't be able to start on the engine for awhile. Also, I might
be going back to work soon, so that may put a crimp in my fun, too.


Logged

Craig Shepard
Located in Minnesquito

http://bus.gumpydog.com - "Some Assembly Required"
TomC
Hero Member
*****
Offline Offline

Posts: 6901





Ignore
« Reply #14 on: January 29, 2008, 11:00:59 PM »

Watch out for the cheapo 3600rpm gen heads.  I know of one gen company that was using some made in Italy, that on a 4,000 watt genset for a boat, when a 30 amp load was put on the gen, the heat coming out of the gen vents was almost hot enough to burn you.  Whereas on my Powertech 10kw (Marathon brushless), I have put a 9,000 watt load on it and also felt the air coming out of the gen vents, and it was just a little bit warm.  Excess heat produced when generating a load is a sign of whether a generator has efficient windings and clearances.  If your genset puts out too much heat when generating, your wasting engine energy to overcome the cheapo windings on the generator-which ultimately means burning more fuel to create the same amount of electricity.  Good Luck, TomC
Logged

Tom & Donna Christman. '77 AMGeneral 10240B; 8V-71TATAIC V730.
gumpy
Some Assembly Required
Hero Member
*****
Offline Offline

Posts: 3318


Slightly modified 1982 MC9


WWW

Ignore
« Reply #15 on: January 30, 2008, 06:16:00 AM »

The head I have is a Leroy Somer head. It is rated at 3600 rpm, and 7.5 Kw, if I remember correctly.
Logged

Craig Shepard
Located in Minnesquito

http://bus.gumpydog.com - "Some Assembly Required"
belfert
Hero Member
*****
Offline Offline

Posts: 5451




Ignore
« Reply #16 on: January 30, 2008, 06:22:40 AM »

I'm guessing you gave up on the Powertech genset like mine.  You did say you thought it would be just a hair too big for your compartment.  I'm sure expense is another big issue.

You should have a good genset and done right it would probably be quieter than the Powertech.
Logged

Brian Elfert - 1995 Dina Viaggio 1000 Series 60/B500 - 75% done but usable - Minneapolis, MN
gumpy
Some Assembly Required
Hero Member
*****
Offline Offline

Posts: 3318


Slightly modified 1982 MC9


WWW

Ignore
« Reply #17 on: January 30, 2008, 06:38:31 AM »

I'm guessing you gave up on the Powertech genset like mine.  You did say you thought it would be just a hair too big for your compartment.  I'm sure expense is another big issue.

You should have a good genset and done right it would probably be quieter than the Powertech.

Haven't totally given up on it. I just got cheap this spring. Being out of work for a year has tightened my wallet some. And, I have the engine and head sitting in the garage, taking up valuable space, so thought maybe I should go ahead and get it going before it gets warm enough to work outside.

I'm still thinking about that 3Kw Powertech unit. I think I could make it work for my needs, it's less $$$ than the 8Kw, and is smaller footprint. I wish they made a 4Kw or 5Kw unit.

Logged

Craig Shepard
Located in Minnesquito

http://bus.gumpydog.com - "Some Assembly Required"
DrivingMissLazy
Hero Member
*****
Offline Offline

Posts: 2634




Ignore
« Reply #18 on: January 30, 2008, 06:47:27 AM »

The head I have is a Leroy Somer head. It is rated at 3600 rpm, and 7.5 Kw, if I remember correctly.

The Leroy Somer alternator is manufactured in France. I used to use them occasionally when I needed to build a really Cheap Charlie unit. They are inherently regulated so the output voltage is dependent on both the rpm and the load. OK for an industrial unit for use on a construction site running Skil saws and the like. As i recall the regulation is about +- 5%. The output voltage is typically not adjustable.

Richard
Logged

Life should NOT be a journey to the grave with the intention of arriving safely in an attractive and well preserved body. But rather to skid in sideways, chocolate in one hand, a good Reisling in the other, body thoroughly used up, totally worn out and screaming:  WOO HOO, what a ride
gumpy
Some Assembly Required
Hero Member
*****
Offline Offline

Posts: 3318


Slightly modified 1982 MC9


WWW

Ignore
« Reply #19 on: January 30, 2008, 08:22:34 AM »

Well, that's not what I wanted to hear!

I was under the impression these were better units than that, based on the information I got before I purchased it. Maybe
I'd have been better off going with the unit from Northern Tool. I got a good buy on this head, though. It was cheaper
than the NT unit.

So, how does one go about correcting the voltage regulation?  That sounds like it might cause some issues with my Trace
inverter. Although, if it can maintain 120v +/- 5% (6 volts), it might be ok as long as the frequency is stable within about
2 hz.

Logged

Craig Shepard
Located in Minnesquito

http://bus.gumpydog.com - "Some Assembly Required"
DrivingMissLazy
Hero Member
*****
Offline Offline

Posts: 2634




Ignore
« Reply #20 on: January 30, 2008, 08:55:28 AM »

Well, that's not what I wanted to hear!

I was under the impression these were better units than that, based on the information I got before I purchased it. Maybe
I'd have been better off going with the unit from Northern Tool. I got a good buy on this head, though. It was cheaper
than the NT unit.

So, how does one go about correcting the voltage regulation?  That sounds like it might cause some issues with my Trace
inverter. Although, if it can maintain 120v +/- 5% (6 volts), it might be ok as long as the frequency is stable within about
2 hz.



I suspect that the Northern Lights unit would be similar in quality. I would suggest you try and track down the specs on the head you have. I believe Emerson Electric purchased Leroy Somer several years ago. As I recall, some of their devices had the capability of accepting an input to control the output voltage, but it has been 20 years since I was involved in this product. I did import a large number of the larger 1800 rpm brushless synchronous types for my production and they were very high quality units. I also imported a lot of units from England but the brand name escapes me right now.

Richard
« Last Edit: January 30, 2008, 08:57:11 AM by DrivingMissLazy » Logged

Life should NOT be a journey to the grave with the intention of arriving safely in an attractive and well preserved body. But rather to skid in sideways, chocolate in one hand, a good Reisling in the other, body thoroughly used up, totally worn out and screaming:  WOO HOO, what a ride
TomC
Hero Member
*****
Offline Offline

Posts: 6901





Ignore
« Reply #21 on: January 30, 2008, 10:07:57 AM »

Powertech makes a 5kw for the trucking industry-called an APU-is actually a 5500 watt gen head rated at 5000 watts powered by either a 2 cylinder Kubota or Caterpillar.  Engine runs at about 2200 and the gen is a 3600.  Is mounted in a cabinet that requires the cover to be on since it uses pressurized cooling-meaning the engine fan sucks the air into the cabinet, pressurizes the cabinet then the air seeks the least resistance to get back out which in this case is going through the radiator.  Nice unit, about $4800.  Good Luck, TomC
Logged

Tom & Donna Christman. '77 AMGeneral 10240B; 8V-71TATAIC V730.
NCbob
Hero Member
*****
Offline Offline

Posts: 1261


"Foolish Pleasure" 35' MC5A




Ignore
« Reply #22 on: January 30, 2008, 11:53:02 AM »

Sorry Craig, have to agree with Richard.  Leroy Somer was a piece of $hit.  Do yourself a favor and find a quality generator to complete your package.

Just a thought.....Machinery's Manual will give you the shortcuts and tables for figuring the size of your pulleys.

Gary has a copy and since he's recuperating from back surgery (it went well for those of you who know Gary
and he'd love the challenge of figuring out the possibilities for you.

Bob
Logged

True friends are difficult to find, hard to leave and impossible to forget.
DrivingMissLazy
Hero Member
*****
Offline Offline

Posts: 2634




Ignore
« Reply #23 on: January 30, 2008, 07:23:48 PM »

It is not the 3600 RPM or 1800 RPM that is critical. It is the actual design and construction of the alternator.

Most alternators built for the construction trade are built as cheap as possible since many contractors throw them away at the end of a construction project.

To build a cheap alternator there are several steps that can be taken. Since less copper and steel is required for a higher rpm unit, they are typically 3600 RPM. Since out put voltage is typically not critical to run a cutoff say, they are inherently regulated. That means that the output voltage is dependant on speed and load and the amount of capacitive feedback used to control the output. Since the output waveform (harmonic distortion) is not important, then the construction is typically such that the distortion is over 5%.

To get a good alternator, it must be constructed to provide low harmonic distortion and be a brushless synchronous revolving field type to permit precise voltage regulation.

Richard
Logged

Life should NOT be a journey to the grave with the intention of arriving safely in an attractive and well preserved body. But rather to skid in sideways, chocolate in one hand, a good Reisling in the other, body thoroughly used up, totally worn out and screaming:  WOO HOO, what a ride
donnreeves
Jr. Member
**
Offline Offline

Posts: 72





Ignore
« Reply #24 on: January 31, 2008, 05:43:26 AM »

For a really good-cheap generator head, Try looking for an old MH series Onan. I Just mated a 6.5 Onan head to a D600 three cyl. Kubota. All I had to do was have a drive shaft machined that bolts to the flywheel, and fab up a bell housing. I also had the machinist make up a centering disk that slips over the drive shaft to center the bell housing. The tolerances are pretty tight, so alighnment is critical. AS far as engine speed goes, I never heard of hertz. I thought they were a car rental company. Didn't know they did electrical work too. Seriously I just cranked the rpm up untill it read 120V. The governor doesn't seem to keep up with the changes in load very well. I have the voltage set at 124V static and it drops to 114V  at full load. I'm Assuming after reading the above posts that this is the wrong approch. Could one of you electrical gurus please enlighten me. Thanks  Donn
Logged
Stan
Hero Member
*****
Offline Offline

Posts: 973




Ignore
« Reply #25 on: January 31, 2008, 05:53:14 AM »

Richard: Please excuse my dumb questions.
1.  When you say 'inherently regulated' are you referring to the type that uses a bridge rectifier to feed some output back into the field, or some other method?
2. In a 'brushless, synchronous revolving field type' how is the voltage regulator connected to the field?
Thanks for the help.
Logged
JackConrad
Orange Blossom Special II
Global Moderator
Hero Member
*****
Offline Offline

Posts: 4447


73' MC-8 8V71/HT740 Southwest Florida


WWW
« Reply #26 on: January 31, 2008, 06:09:46 AM »

   When we had our old (almost antique) Onan, I was told to set the RPM using a frequency meter. I don't remember who explained the procedure to me, but they said to set the RPM to get 62 cycles with no load. When a load was applied, the cycles would be 59 or 60.
   Last year we installed an Energy Management Systems AC monitor on our bus. The EMS monitors both voltage and cycles. If either is out of range it disconnects the bus from the power supply. My understanding (might not be correct) is that cycles are just as important as voltage.  Jack
Logged

Growing Older Is Mandatory, Growing Up Is Optional
Arcadia, Florida, When we are home
http://s682.photobucket.com/albums/vv186/OBS-JC/
Stan
Hero Member
*****
Offline Offline

Posts: 973




Ignore
« Reply #27 on: January 31, 2008, 07:49:24 AM »

On good quality gensets with good electronic regulators, output voltage is controlled almost instantaneously by field current. A good regulator will control the voltage so that you see no movement on an analog voltmeter going from no load to full load.

Frequency is a function of speed and there is always some time lag between applying a load and the engine responds to the governor. Just like your bus engine, you have to set the no load speed a little high so that you have the correct speed at full load.

Most things are not particularly sensitive to frequency. The frequency from you utility company varies during the day as the load changes. Their target is a 60 hz average over 24 hours. A 2 hz change in frequency will give you a 3.3% change in motor speed but most electronic equipment has an internal power supply that is not sensitive to input frequency.
Logged
gumpy
Some Assembly Required
Hero Member
*****
Offline Offline

Posts: 3318


Slightly modified 1982 MC9


WWW

Ignore
« Reply #28 on: January 31, 2008, 08:17:51 AM »

So I looked at the documentation I have on the Leroy Somer head. It's and LSA 35 L9 "E".  It says it's brushless, but
it does indeed indicate a +/- 5% accuracy and <= 5% Telefonic Harmonic Factor (whatever that is).

I guess I don't know what all this is gonna mean in terms of usability. I understand that the frequency needs to be set by
engine RPM, and I know that my Trace SW inverter is sensitive to this. I currently use a jobsite Coleman generator when
we're camping and I have to manually tweak the throttle while watching the inverter frequency display to get it to work.
If I get it set within 1 hz, all is well, but if the engine speed changes and the frequency goes away from 60hz by more than
2 hz, the inverter will kick it out and I have to start all over. It's very touchy. I think I can adjust that tolerance some on the inverter, but really don't want to go too wide. So, I'm hoping my engine will handle load changes well and I won't have that
problem.

As for the voltage, that seems to have a very wide range on the inverter, with limits from 109 v to 132 v. So, if this head is within 5% of it's rated 120 volts, I think it should be ok with my inverter. It seems the frequency is more important to the
inverter than the voltage is.

Does any of this sound logical?



Logged

Craig Shepard
Located in Minnesquito

http://bus.gumpydog.com - "Some Assembly Required"
DrivingMissLazy
Hero Member
*****
Offline Offline

Posts: 2634




Ignore
« Reply #29 on: January 31, 2008, 08:43:32 AM »

Richard: Please excuse my dumb questions.
1.  When you say 'inherently regulated' are you referring to the type that uses a bridge rectifier to feed some output back into the field, or some other method?
2. In a 'brushless, synchronous revolving field type' how is the voltage regulator connected to the field?
Thanks for the help.

The two types of alternators typically in use today are the inherently regulated, and the revolving field.

You are correct, the inherently regulated uses an internal circuit to control the output voltage, based on current flow and there is no adjustment (generally) available to actually set the voltage.

The revolving field alternator has  separate windings on both the rotor and the stator, in addition to the main power windings. In operation, a variable DC voltage is applied to the exciter stator winding. This voltage is derived from the voltage regulator. This applied DC voltage creates a magnetic field which creates a voltage in the exciter rotor winding. Since the rotor is rotating this is an AC voltage whose frequency is determined by the speed of the rotor and the number of poles on the exciter winding. It is typically significantly higher than the nominal output of the alternator (120 hertz I believe) and is three phase.

This three phase AC voltage is connected thru a set of diodes which converts it  to DC and is connected to the rotating exciter of the main alternator. This DC voltage then induced an AC voltage in the stator (stationary) windings of the main alternator and that is where the output voltage is derived.

The voltage regulator is an electronic device that looks at the AC output of the alternator and creates a DC output that is proportional to the AC input. The DC output is fed to the exciter field as outlined above and the rest is history.

There are some other types of alternators, but they are not in general use in the market today. One I recall is a permanent magnet unit. Permanent magnets, installed in the stator of the exciter create the magnetic field to cause the exciter rotor to generate an AC voltage.

Richard
Logged

Life should NOT be a journey to the grave with the intention of arriving safely in an attractive and well preserved body. But rather to skid in sideways, chocolate in one hand, a good Reisling in the other, body thoroughly used up, totally worn out and screaming:  WOO HOO, what a ride
DrivingMissLazy
Hero Member
*****
Offline Offline

Posts: 2634




Ignore
« Reply #30 on: January 31, 2008, 09:00:18 AM »

On good quality gensets with good electronic regulators, output voltage is controlled almost instantaneously by field current. A good regulator will control the voltage so that you see no movement on an analog voltmeter going from no load to full load.

Dip and overshoot are the two common expressions that define the response of the alternator to application and removal of full load. It may be as much as 20% depending on the design of the alternator and the regulator. Many times I utilized a significantly over sized alternator to reduce this problem.

Quote
Frequency is a function of speed and there is always some time lag between applying a load and the engine responds to the governor. Just like your bus engine, you have to set the no load speed a little high so that you have the correct speed at full load.

Correct. Frequency regulation is typically very poor on small sized gensets. On larger units we typically used a gear tooth counter on the flywheel to detect and correct frequency.

Quote
Most things are not particularly sensitive to frequency. The frequency from you utility company varies during the day as the load changes. Their target is a 60 hz average over 24 hours. A 2 hz change in frequency will give you a 3.3% change in motor speed but most electronic equipment has an internal power supply that is not sensitive to input frequency.

This was correct in the older times but anymore the frequency is very stable since the electrical grid is connected thru out the country and frequency variations are in the thousands of a hertz and corrected plus or minus to an atomic clock frequency every night at midnight.

Richard
Logged

Life should NOT be a journey to the grave with the intention of arriving safely in an attractive and well preserved body. But rather to skid in sideways, chocolate in one hand, a good Reisling in the other, body thoroughly used up, totally worn out and screaming:  WOO HOO, what a ride
TomC
Hero Member
*****
Offline Offline

Posts: 6901





Ignore
« Reply #31 on: January 31, 2008, 09:33:24 AM »

I have a Powertech 10kw powered by a Kubota 4 cylinder and a Marathon brushless alternator (big).  The governor is very sensitive in that it is set at 62 hertz at no load and at full 10kw output is at 59.5.  On any Kubota, there are special springs you can install in the engine governor for maximum rpm control at 1800rpm-original springs are for 3600rpm. 

Setting and having a close control over hertz in alternating current is very important for running motors-like A/C's-otherwise with a slow running generator can cause undue current draw, overheating of the motor, and possible failure of the motor.  Other sensitive appliances are anything electronic.  About the only electrical appliance that is not sensitive to hertz will be a heating element or a light. 

Personally believe that the generator is the heart of the house part of the bus.  There is nothing more frustrating than a generator that is finicky, consumes a lot of your time and money just to keep it running.  On the other hand, having a quality built generator like the Powertech, or Wrico, it is pure pleasure when all you have to do is to change the oil and filter periodically and they just run and run without a second thought.  Do yourself a favor and spend the money on a good quality name brand generator-you'll be thanking yourself every time it is running hours on end with no problems.  Good Luck, TomC
Logged

Tom & Donna Christman. '77 AMGeneral 10240B; 8V-71TATAIC V730.
DrivingMissLazy
Hero Member
*****
Offline Offline

Posts: 2634




Ignore
« Reply #32 on: January 31, 2008, 09:36:11 AM »

I have a Powertech 10kw powered by a Kubota 4 cylinder and a Marathon brushless alternator (big).  The governor is very sensitive in that it is set at 62 hertz at no load and at full 10kw output is at 59.5.  On any Kubota, there are special springs you can install in the engine governor for maximum rpm control at 1800rpm-original springs are for 3600rpm. 

Setting and having a close control over hertz in alternating current is very important for running motors-like A/C's-otherwise with a slow running generator can cause undue current draw, overheating of the motor, and possible failure of the motor.  Other sensitive appliances are anything electronic.  About the only electrical appliance that is not sensitive to hertz will be a heating element or a light. 

Personally believe that the generator is the heart of the house part of the bus.  There is nothing more frustrating than a generator that is finicky, consumes a lot of your time and money just to keep it running.  On the other hand, having a quality built generator like the Powertech, or Wrico, it is pure pleasure when all you have to do is to change the oil and filter periodically and they just run and run without a second thought.  Do yourself a favor and spend the money on a good quality name brand generator-you'll be thanking yourself every time it is running hours on end with no problems.  Good Luck, TomC

In my opinion Tom, you are 100% right on.

Richard
Logged

Life should NOT be a journey to the grave with the intention of arriving safely in an attractive and well preserved body. But rather to skid in sideways, chocolate in one hand, a good Reisling in the other, body thoroughly used up, totally worn out and screaming:  WOO HOO, what a ride
Stan
Hero Member
*****
Offline Offline

Posts: 973




Ignore
« Reply #33 on: January 31, 2008, 10:39:30 AM »

Richard: One more question on the brushless alternator. Are there two separate rotors or are all the windings in the same slots.

Your comment about 20% voltage swing on load change. I hope that didn't occur for more than 1 or 2 cycles. On a slip ring type rotor, they will correct that fast. I used to rebuild regulators for a company that rented 200 - 600 kw plants and they wouldn't accept the regulator if they could see a 6" panel meter move when they dumped on full load in a load bank.

Many generating stations connect into the grid on DC lines so they are isolated from a standard frequency on the grid. I have a friend who is a shift engineer at a power plant with steam turbines. I will ask him how they control the speed to that kind of tolerance with changing load.  He has told me how many degrees tolerance they have when switching a generator onto the system. (but I don't remember). Sad
Logged
DrivingMissLazy
Hero Member
*****
Offline Offline

Posts: 2634




Ignore
« Reply #34 on: January 31, 2008, 12:46:54 PM »

Richard: One more question on the brushless alternator. Are there two separate rotors or are all the windings in the same slots.


Yes, they are two completely seperate units on the same shaft. The exciter is significantly smaller and is really another brushless alternator. In the 500 watt range I believe, but it has been many years since I have been involved with them.


Quote
Your comment about 20% voltage swing on load change. I hope that didn't occur for more than 1 or 2 cycles. On a slip ring type rotor, they will correct that fast. I used to rebuild regulators for a company that rented 200 - 600 kw plants and they wouldn't accept the regulator if they could see a 6" panel meter move when they dumped on full load in a load bank.


20% is typically worst case and most of the time it is better than that, depending on what the actual load is and how well it will tolerate the dip. Recovery from dip or overshoot was typically measured in milliseconds.

In many cases I might start with an alternator that was double the size required to reduce the dip. In other words I might use a 500KW alternator when the maximum connected load would only be 250KW. Therefore a 100% load change would be 250KW on a 500KW unit. The computers back in the 70's were very sensitive to sudden voltage or frequency changes. I sometimes added a large flywheel to prevent frequency variation when a sudden load was placed on the engine genset.

On AC motor gensets I utilized synchronous motors so that the frequency would not vary if there was a large load change. Synchronous motors run at exactly 1800 rpm regardless of load or voltage change as long as it is within the operating parameters of the motor.

Quote

Many generating stations connect into the grid on DC lines so they are isolated from a standard frequency on the grid. I have a friend who is a shift engineer at a power plant with steam turbines. I will ask him how they control the speed to that kind of tolerance with changing load.  He has told me how many degrees tolerance they have when switching a generator onto the system. (but I don't remember). Sad


For more detailed information about the North American Power Grid you might want to review this site:
http://en.wikipedia.org/wiki/North_American_Electric_Reliability_Council

NERC was formed back in the 60's and I was an active member at one time many years ago.
This pretty well describes the system and how all the AC power grids throughout the country are now tied together into one massive grid. Individual power plants no longer have much effect on the overall grid.

Richard
Logged

Life should NOT be a journey to the grave with the intention of arriving safely in an attractive and well preserved body. But rather to skid in sideways, chocolate in one hand, a good Reisling in the other, body thoroughly used up, totally worn out and screaming:  WOO HOO, what a ride
TomC
Hero Member
*****
Offline Offline

Posts: 6901





Ignore
« Reply #35 on: January 31, 2008, 12:56:32 PM »

On brushless generators, or alternators, to better picture what they look like, when you take the end cover off the alternator, what you'll see is a small alternator (about the size of a truck alternator, but without the case) mounted on the end of the rotating armature windings.  So the brushless exciting small alternator pumps current into the rotating armature windings that create the magnetic field that is picked up by the stationary field windings mounted in the case that creates the electricity.
On a slip ring type, the battery voltage or 12v is pumped directly through slip rings into the armature, where it creates the magnetic field that is picked up by the surrounding stationary fields.  Good Luck, TomC
Logged

Tom & Donna Christman. '77 AMGeneral 10240B; 8V-71TATAIC V730.
Pages: 1 2 3 [All]   Go Up
  Print  
 
Jump to:  

Powered by MySQL Powered by PHP Powered by SMF 1.1.18 | SMF © 2013, Simple Machines Valid XHTML 1.0! Valid CSS!