[Gasification] small scale gasifiers for those that need them with engine speed controllers

Thu Jul 5 21:10:56 EDT 2007

Dear GF

gfwhell at aol.com wrote:
> Controlling an alternator for the output of a steady frequency, say
> 60 hertz is relatively simple. or you could purchase a car cruise
> control. You order up a couple of synchronous gearbox timer motors
> from Surplus center. 
> http://www.surpluscenter.com/sort.asp?UID=2007070423332521&catname=electric&keyword=MTSM
>  Item 1055-D @ $0.89c each. These motors are identical, with an
> output shaft turning @ 16 RPM.

According to the Catalog, the speed is 30 RPH, or only about 1/2 RPM. 
Wouldn't the response speed be unreasonably slow?

Best wishes

Kevin
  You will mount these, ?with each shaft
> having a thrust bearing attached. there will be a central disk with
> an actuating arm inserted between these two motor driven bearings. 
> ?Provided the motors are urged toward each other by a suitable
> spring. the sandwiched actuating disk will be locked stationary in
> between them .When one?OR the other motor is?energized. the actuator
> disk will rotate , at a lesser speed in the direction of the
> energized motor. If both are energized, the actuator will remain
> stationary. The motors are synchronous, there for, if one is fed with
> a standard fixed frequency. say, from a small shaver inverter supply.
> and the other is fed from a phase of the alternator. it will be
> possible to control the throttle mechanism, using the arm attached to
> the middle disk of the bearing assembly, ?sandwiched between the two
> motors, The alternator is set at the required speed by easing the
> spring pressure and moving the arm into the required control
> position. Should the alternator slow down under load the controlling
> motor will also slow due to the lower frequency. causing the throttle
> to be?opened by the reference motor driven by the inverter.This
> closed loop control works really well if the leverage and reaction
> speed is good.this is dependant upon the size of the balls in the
> thrust bearings. together with the motor type, and the way its put
> together. mini timing belts could be employed keeping friction to a
> minimum and linear movement instead of an arm. I ran one of these
> controls for eight hour shifts and the electric clock, driven by the
> main bus was only one minute slow.
> 
> 
> -----Original Message----- From: Kevin Chisholm
> <kchisholm at ca.inter.net> To: Discussion of biomass pyrolysis and
> gasification <gasification at listserv.repp.org> Sent: Wed, 20 Jun 2007
> 10:54 pm Subject: Re: [Gasification] small scale gasifiers for those
> that need them
> 
> 
> 
> Dear Peter
> 
> Peter Singfield wrote:
>> At 04:49 PM 6/20/2007 -0300, Kevin Chisholm wrote:
>>> Dear Peter
>>> 
>>> Given that he has an engine built for constant speed governor
>>> operation, and a 5 kW AC generator already in place, how would
>>> you suggest that he "go to DC?"
> ...del..
> 
>> As voltage goes up -- the battery charge amperage goes up --
>> 
>> The DC Permanent Magnet Alternators are 90 to 95% efficiency.
> 
> That is true. You didn't mention Permanent Magnet Generators... you
> were talking about DC welder generators. ...del...
>> The entire process is finished in a few hours -- and adjustment is
>> done roughly every 30 minutes.
>> 
>> Yes -- it could be done electronically -- in fact it is being done
>> exactly this way -- to achieve incredible efficiencies -- in the
>> new line of Inverter Gensets.
>> 
>> Want the urls Kevin??
> 
> Yes, please forward them to the List.
>> Anyway -- they use a PM DC alternator to charge a battery - -and
>> the inverter runs from the battery. But it is a small battery --
>> just enough to handle surges and make up for governor lag.
>> 
>> The big advantage in fuel savings in these units is the on the roll
>>  derating that can then be accomplished -- smoothly.
> 
> I question this. I have never yet seen an engine that had a Specific
>  Fuel Consumption that was better than the SFC close to rated output
> of the engine. This "sweet spot" is usually at 80% to 90% of maximum
> rated engine speed. Everything I have seen suggests that running at 
> significantly lower speed and at significantly lower % of engine
> power rating will drive up the SFC significantly, and result in worse
> fuel economy than if the right engine had been selected in the first
> place. Do you have any URL's that show differently?
>> On to your next "question"
>>>> Charge rates will govern your engine's revolution.
>>> Wouldn't he have to junk the present mechanical governor and
>>> replace it with a new electronic governor?
>> I your land -- yes -- but here we find electronic components are a
>> much added extra expense -- and just one more item to fail -- which
>> they tend to do in the tropics more rapidly than in Canada.
> 
> If the mechanical governor that was supplied with the engine is not 
> capable of the degree of regulation required for good generator 
> operation, what is his alternative, other than purchasing an
> electronic governor?
>> Reg is in the "tropics" -- by the way.
>> 
>>>> That is how we are doing it here -- with diesel engines and DC
>>>> welder ? generators.
>>> Isn't that a step backwards? Why not use a battery voltage
>>> regulator that shuts off the charger when the battery is up to
>>> voltage?
>> Another topic that takes much explaining -- -
>> 
>> To totally charge a battery -- top it off -- so to speak -- you
>> must spend long periods trickling a minor charge in.
>> 
>> We here are doing fast charge cycles only. Couple of hours -- max.
>> 
>> We also do not discharge the battery packs more than 30% -- else
>> they do not live long --
>> 
>> Further -- they reach full "fast-charge" basically always after the
>> same run time -- so it is not feeling the battery for 2 hours
>> straight -- but just at the two hour point. If not warm -- let it
>> run another 15 minutes -- feel again.
>> 
>> In practice they have their children trained to do just that -- and
>> turn the engines off -- "when".
> 
> A charge controller would be simpler and more reliable.
>> 
> ...del...
> 
>>> If he went to a 5 kW DC generator, he would have to get a 5 kW
>>> inverter. I cxannot see where there is a potential for a "great
>>> increase in efficiency." The cost of a 5 kW inverter would be
>>> excessive.
>>> 
>> I do sell 3 kw inverters (6 kw surge) for $370 US here --
> 
> These are probably square wave inverters which I understand are OK
> for tools, except that they result in less efficient tool motor
> operation, but which can cause problems with computers and electronic
> equipment.
>> But in real terms they never use more than what a one kw inverters?
>> -- the ones I sell here for $110 will run your standard skill saw
>> -- thus all drills -- grinders -- etc -- a small washing machine --
>> one of those energy efficient small freezers I import (90 watts) --
>> CF lights -- and a fan or two or three.
> 
> Peter, you are basically telling him to start from scratch with a new
> system
>> Mind you -- you do have to do load sharing.
>> 
>> Reg says one KW would be fine for him -- (Oops -- we have been
>> chatting "off-list" as this is -- by the way -- all off-topic
>> (according to the "rules") stuff)
>> 
>>> I would think he would be better off to fix his existing
>>> Governor, and if that is not possible, then replace it with an
>>> external electronic governor and throttle actuator.
>>> 
>> I made up a governor that runs off the shaft of the generator --
>> that works well to.
> 
> Is he going to buy one from you? Will it give the preferred +/-3% or
>  better speed control that is preferred for generators?
>> My concern is fixated on conserving energy -- and by conserving
>> energy we find we do not need go to the headaches of using a
>> gasifier -- as we reduce energy costs to such a great extent the
>> price of diesel then works out to the same -- as saying -- 1990 --
>> and using an inefficient 1990 system. Following me??
> 
> Regrettably, I don't follow you. He has a gasifier to produce fuel
> gas for his engine. How can he eliminate the headaches of the
> gasifier??
>> Kevin -- in the set up I produce here the engine is run heavily
>> derated as well -- it is all "adjusted" by pulley to belt drive
>> ratios --
>> 
> Have you ever run tests to show the Specific Fuel Consumption in
> terms of gms fuel/hr per kW of output on your de-rated engines?
> 
> Best wishes,
> 
> Kevin
> 
> 
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