Leece neviille 4800 series j mount ?

[vwbeamer]

Was wanting to build a Alternator powered Inverter set up.


Goal- to provide 3000 watts emergency backup power and semi portable power to run power tools etc.  This will also be a test mule for propane engine controls. Want to develop a portable power source that gets great fuel efficiency.

Parts-

Engine- 212cc Honda clone  rated at 7hp (Will convert to propane, more than likely will knock it down to 5.5 to 6 hp)

ALT. 4800 series LN, 200amp, 14 volt.

Battery- 27d deepcycle 12 volt 100AH. Battery is only in the system to to provide uninterrupted power  and to help meet the demand of a surge.

Inverter- none yet need about 3000 watts ( fridge, microwave, TV, LED lights, Laptop)

Drive will be serpentine belt. 4.2 inch utterpower pulley on motor and approx 2.5 inch pulley on the alt. I can't remember the exact size, but it maybe as small as 2.3 or so. Anyway my ratio should end up be 1.7-to 1.80, somewhere in that range.

Question i have the 14 volt 200 amp LN 4800 series J mount ( sorry can't remember exact model, it's in FL now and I'm in GA).

I was wondering If i might be better off to spend the $150 or so and get the 110-555 and another battery go with a 24 volt system, Like Bob has ingenuously and graciously described in his white paper.  The extra cost would about double my project budget. ( another battery, New alt, balmar reg)

My original plan was to use a stepper motor and microprocessor to control the engines governor speed. So that it would run slow when load was low, and then speed up when load was higher. I was also hoping that I could open the governor up quick enough to avoid the engine from stalling or straining under load.

The hold up for me going to the 110-555 and 24 volt setup is is the Balmer regulator. I think it's possible that I maybe able to mimic some of it's functions with a microprocessor , kind of build my own. Problem is if I start experimenting with $150 alternators and fry them i could have bought the balmar. Is there a cheaper regulator?  would not any external regulator work, or I'm I missing something?Also another deepcycle battery makes the unit heavier and harder to move.

[mobile_bob]

welcome aboard

your mount in question is referred to as a j180 mount

the 2.3 serp pulley is a common truck pulley and is about as small as you can get away with in my opinion, it generally is an 8 groove.

if efficiency is the ultimate goal i would forgo the use of the leece neville, it will be only a bit over 50% at full load, and it is doubtful you will get anywhere near max output with 5.5 hp, in my opinion

its no secret that i love the 555 series alternator

there are alternative regulators to the balmar
sterling makes one, for less than half the price, and i am thinking that they have one in the 100 dollar range that is compatible with what i have done in the white paper.

search ebay for "sterling regulator"

the important thing is the need for remote sense capability, and you will also need a 12volt isolated supply for the field, if you want to do the 24volt thing as described in the white paper.

the need for highly accurate speed control is unnecessary, so that makes building a microprocessor controlled speed system much easier in my opinion.

hope this helps
bob g

[vwbeamer]

Thanks Bob. I was hoping you would help me.

I pretty sure my pulley is 2.3, after looking at what is offered. That gives me a max ALT shaft speed of about 6500RPM. Or I could buy a larger 2. 9 pulley and give my self a little more torque at the shaft. Then my maximum shaft speed would only be about 5200 rpm.

What RPM range I'm I looking at for the 555 running 28 volts?  I'm guessing 2500 ALT shaft RPM and up.

So would think the 1.43 ratio or 1.8 ratio would be better?

[mobile_bob]

i personally would target about 3500rpm or so, alternator rpm
this will give you some room to play with, and good cooling.

bob g

[vwbeamer]

Thanks. tell me if I have this right. The 3500 rpm would be the min speed?



So with a 1.43 ratio. and varying the speed with load based on amps.

               Engine speed         Alt Shaft speed

Low load    2500 rpm                       3575 rpm

Med load     3000 rpm                      4290 rpm

Max load     3600 rpm                       5148 rpm


According to my Math, if the Alt is 70% efficient and the inverter is 90%, I should be able to run a continuous 2500 watts 120 AC

So I should need about 110 amps at 28 volts from the 110-55.

So my last question is can I get 110 amps at ALT shaft 5148 rpm ?

[mobile_bob]

the 555 will deliver 130amps hot, at 28.8vdc at 4800rpm, however that is about as hard
as i would drive it,,

i would have no problem doing so for short durations, maybe 10 minutes on and backed off, that is why i decided to stick to 100amps max at 28.8vdc at the 4800rpm.
under which conditions the unit is thermally stable and can run continuously at that level.

now having said that, i also need to note this
because my alternator mounting is such that i have to spin it backwards, which is counter to the directional fan, it might well be the unit could do the 130amps continuous if i were to turn it around and/or spin it a bit faster.

fwiw
bob g

[Ronmar]

My only concern with a variable RPM genset such as you propose, is that I think the engine controller needs to be able to talk to the charge controller to limit the application of field to allow the engine time to ramp up RPM after sudden load increases... If it dosn't I could see the charge controller/regulator sensing the drop in DC voltage from a sudden high load, quickly putting the engine behind the power curve at low RPM.

At the very least, a programmable charge controller/regulator set to apply field increases at a rate slow enough that the engine controller can increase the engine RPM to deal with a load increas.   

[vwbeamer]

Thanks for the replies. They are much appreciated.

Ronmar, I share your fear , but i believe my algorithm will be able to deal with it.

My plan is to build the complete unit without the rpm controller.

I will then set the engine speed to 2500 rpm and load the inverter until the engine rpm starts to drop. Then taking note of that load in amps, I will multiply it by 80%. I will repeat this measurement at several rpms, more than likely every 200 rpm. This will allow me to build a 2D map based on amps consumed and engine rpm. At each rpm the motor will run at a 80% load. if the load is greater, then it will instantly go to the appropriate rpm  for the amp load detected.

This way i hope to always be running at 80% throttle, no matter what rpm. ( unless the load is less at the lowest rpm) I believe this will work because the governor on the engine controls engine speed, not throttle.

This should give me the best fuel economy and also give me a 20% reserve on engine power, plus the 100ah 24 volt battery pack. also remember the engine speed controller will be asking for more engine rpm as soon as it detects an increase in amp draw.

I think it will work, but this is why I wanted to ask. This thread has already vastly improved my design and been a great help.

If doesn't work then I will try to incorporate your idea.

EDITED to clarify my idea.

[Ronmar]

With the engine controller monitoring the current output, that might work out.  With the batteries in there to buffer the loading of the alternator, the current draw should increase before the voltage drops so far that it triggers a massive response from the voltage regulator to increase alternator output/engine load...  But without some control/delay of the voltage reg on the alternator, it still might outpace engine capacity...

Sounds like an interesting project...

[Lloyd]

My only concern with a variable RPM genset such as you propose, is that I think the engine controller needs to be able to talk to the charge controller to limit the application of field to allow the engine time to ramp up RPM after sudden load increases... If it dosn't I could see the charge controller/regulator sensing the drop in DC voltage from a sudden high load, quickly putting the engine behind the power curve at low RPM.

At the very least, a programmable charge controller/regulator set to apply field increases at a rate slow enough that the engine controller can increase the engine RPM to deal with a load increas.  

Ronmar & Madlabs,

This is the exact approach that i took with my variable speed perky-cat dc charger, which has become an inverter-generator as well. http://www.microcogen.info/index.php?topic=709.0 I am using the Balmar MC614, and Precession Governor. I have a 720 amp hr bank at 12 volt, and a Pure Sine 2800watt Magnum inverter. When acting as inverter gen I can draw 2800 PS AC from the inverter and still put 50 amps charge into the bats at 14.5 volts.

Myine is three speed #1. start up at 1000 rpm  no power to the field, after warm up #2. Governor ramps up to 1800 rpm, turns the field on, and shorts the bat temp sensor(small engine mode on the Balmar) The Balmar ramps up the field after a time delay the governor ramps to #3. 2500 rpm opens the small engine mode switch and the gen is at full output.

Then after bulk charge a Voltage/current sense switch, when 14.8 and less then 80 amps current, shorts the SME mode, and drops the governor back to 1800.

Any time a large load is seen a time delay relay detects the voltage drop when a large load is applied to the inverter, and shorts the SME mode 3 sec time delay again and sends a signal to ramp the governor up to 2500 rpm again.

Lloyd

[vwbeamer]

You have a good idea, I just not sure how I can incorporate it in my design. I will do more research.

With the engine controller monitoring the current output, that might work out.  With the batteries in there to buffer the loading of the alternator, the current draw should increase before the voltage drops so far that it triggers a massive response from the voltage regulator to increase alternator output/engine load...  But without some control/delay of the voltage reg on the alternator, it still might outpace engine capacity...

Sounds like an interesting project...

[vwbeamer]

So I have been thinking. Tell me how this would work.

I have my system as described above. Except I've decided that I need a tach input so i know exactly how fast the engine is spinning. This will also keep my stepper motor in calibration.

My little genverter is humming along at 2500 rpm engine speed, when suddenly the fridge desides to kick on.

My microproccesser detects it because it's monitoring the amps drawn by the inverter.

it then

1. Tells the engine to increase RPM to the speed corresponding to the amps draw as mapped in my above post.
2. Cuts the connection to the 12v excitation source. The inverter is now drawing 100% from the 100AH 24 volt battery pack.
3. Waits until engine reaches desired rpm.
4  reconnects excitation source.

This what I fear now, is the surge caused by the compressor starting will be almost over by the time the motor gets going and the ALT starts producing again.

So the amp draw will drop. And the motor will have reve'd up for no reason, wasting fuel.

Just trying to think of a smart way to do this. i also have the ability to PWM, so i could reduce the cycle on the excitation circuit. But I fear it may confuse the Voltage reg if I do that.

Now I just think I need to build the voltage reg in with my motor speed controller.

I can figure out to program it to do what I want, just need help figuring out what is the ideal solution.

[Ronmar]

I think completely cutting out the field excitation might be a problem.  I think modulating the excitation with PWM via your controller would be the ideal. Then you could set high and low excitation limits to suit the alternator and the available torque.  I am guessing that is how the newer programmable charge controllers are dealing with controlling the field.  You could then control the rate at which it is applied in concert with your RPM increases.  You would then have full control of engine speed and load. 

In answer to your problem scenario, you could program in some delay so short transient loads are handeled by the battery with the engine making up the battery energy used over a longer period after the transient has passed, then the controller responds with an engine and field increase after the longer duration load increase is determined.   

[mobile_bob]

you might consider a current transformer to monitor the load line

the micro could be also monitor it with a buffer circuit adc converter or whatever
and if it sees an increase in load that is longer than a typical motor start (say over 10 seconds) then the coding could direct an increase in engine speed first and then an increase in field current last, so that the engine is never overwhelmed or called upon to increase either speed or field current for a short term motor start type load.

you should probably integrate a CT in the scheme anyway, they are so good at monitoring the load, and actually you could implement them on individual circuits
each of which might have very different power level requirements, such as a well pump, refrigeration,  or perhaps a furnace blower.

so of which are not only must service type loads but are also don't interrupt loads once they are started.   things like furnace blowers must remain powered once called upon by the temp switch to start, otherwise if they shutdown prematurely the furnace goes into overheat and the overheat safety switch has to take over the job of shutting down the furnace,  not something you want to rely on in a good design.

i like CT's and their use in control scheme with microcontrollers for this sort of thing.
they greatly simplify problems and allow much more flexibility in my opinion.

actually they can be used as a logic level device, rather than an analog to digital device.  if you use them on each circuit, and you know what is on that circuit, you really don't need to have digital level info to work with, simply knowing if the load is on or off is good enough.  a micro CT coupled with a discrete component or two, a transistor and you got a simple input to the micro, low and there is no load, high and there is a load on the line.

fwiw
bob g

[Lloyd]

I think completely cutting out the field excitation might be a problem.  I think modulating the excitation with PWM via your controller would be the ideal. Then you could set high and low excitation limits to suit the alternator and the available torque.  I am guessing that is how the newer programmable charge controllers are dealing with controlling the field.  You could then control the rate at which it is applied in concert with your RPM increases.  You would then have full control of engine speed and load.  

In answer to your problem scenario, you could program in some delay so short transient loads are handeled by the battery with the engine making up the battery energy used over a longer period after the transient has passed, then the controller responds with an engine and field increase after the longer duration load increase is determined.  

Ronmar,

That begs a question. The Balmar max charge has the ability to regulate the field of 2 alternators with separate fields and a 10 amp per field PWM . Why not use 1 for the alt and 2 for the throttle solenoid? As the field increases the rpm also increases, use time delay for short term transients that the battery can  handle.

Lloyd