Slow running engine/alternator ideas

[magnetman]

I sometimes wonder if permanent magnet alternators may be an interesting solution for this.

Not looked into it as I do not use rotating electrics for electrical power production unless the Boat is moving. 

 

I have a suspicion in the back of my mind that a PMA and lithium batteries may prove to be good bed fellows if done right.

It would want to be done right. If you install a pma and the Boat catches fire causing you to break your legs as you rapidly exit the vessel without advanced planning don't come running to me to complain.

 

[IanD]

7 minutes ago, magnetman said:

I sometimes wonder if permanent magnet alternators may be an interesting solution for this.

Not looked into it as I do not use rotating electrics for electrical power production unless the Boat is moving. 

 

I have a suspicion in the back of my mind that a PMA and lithium batteries may prove to be good bed fellows if done right.

It would want to be done right. If you install a pma and the Boat catches fire causing you to break your legs as you rapidly exit the vessel without advanced planning don't come running to me to complain.

 

PMAC alternators would be an interesting solution, and you can use any PMAC motor with the appropriate controller exactly like this (they work both ways, that's how regeneration works) and get high efficiency and loads of power for fast-charging batteries -- but you would probably have to write the control algorithms yourself.

 

The problem for most canal boaters is that PMAC is not a cheap solution, the cost would be well into 4 digits, and given that most seem to balk at even the cost of a big expensive alternator... 😉 

Edited March 4 by IanD

[jacko264]

Weld or bold a bigger pulley to the front of the original crank pulley and move the alternator forward 

it would need a bit of engineering  and balancing 

[Bee]

Hard to really tell without standing over the engine but if it was possible to fit a bigger pulley - the usual solution was a washing machine pulley- on spacers so that it cleared the water pump and oil cooler you might get a better speed at the alternator. No doubt this would then foul the engine bearers or some other bit of machinery and the alternator would need moving but it might just work (!) Good luck, Nice engine and engine room by the way.

[Doodlebug]

Okay seeking thoughts again:

 

The engine is resting in a kind of cradle that seems to sit on some wooden joists. Not the best for bolting alternators to I suspect. 
 

I have however found I could get a 10in timing belt pulley and a 1.5in timing belt pulley made up for the alternator. 
 

Does anyone know why the need for an alternator to slip? A timing belt would allow for a much tighter and smaller pulley in the alternator and thus could solve my problem. But why do you never see timing belts used in this way? 
 

many thanks. 

[MtB]

59 minutes ago, Doodlebug said:

Okay seeking thoughts again:

 

The engine is resting in a kind of cradle that seems to sit on some wooden joists. Not the best for bolting alternators to I suspect. 
 

I have however found I could get a 10in timing belt pulley and a 1.5in timing belt pulley made up for the alternator. 
 

Does anyone know why the need for an alternator to slip? A timing belt would allow for a much tighter and smaller pulley in the alternator and thus could solve my problem. But why do you never see timing belts used in this way? 
 

many thanks. 

 

 

There is no need for alternator belt slip. Quite the opposite in fact, belt slip is highly undesirable.

 

Good question about using a cam belt. I think those are not used as vee belts have historically been used and they usually work perfectly well. In your case a toothed cam belt will prolly work well! 

 

I do however wonder if a toothed cam belt might wear prematurely due to the way the angular velocity of the engine varies as it rotates. On some alternators there is an over-run built into the pulley so as the engine slows on the compression stroke, the alternator continues to spin fast (over-runs) as the vee belt drive slows down. A toothed drive belt might be doing a lot of work speeding up then slowing down the alternator several times on every engine revolution.

 

But then I suppose it would be doing the same driving a camshaft...

 

 

[Martin Nicholas]

Toothed belts are fine and used in many applications. They are more efficient and more noisy; noise won't be a problem for your application. You also need a tensioner I would think.

[IanD]

1 hour ago, Martin Nicholas said:

Toothed belts are fine and used in many applications. They are more efficient and more noisy; noise won't be a problem for your application. You also need a tensioner I would think.

Why is a tensioner needed, so long as the alternator can be swivelled (as normal) to set the belt tension?

 

(one would he needed if the end pulley positions are fixed, like when driving a camshaft)

[BEngo]

9 minutes ago, IanD said:

Why is a tensioner needed, so long as the alternator can be swivelled (as normal) to set the belt tension?

 

(one would he needed if the end pulley positions are fixed, like when driving a camshaft)

Toothed belts are very much more sensitive to tension than V  and wedge belts.  Get it wrong and belt life is very short. 

 

Certainly a car alternator type swivel tension arrangement is feasible, but getting it set 'right ' is likely to be difficult and slow.  A proper tensioner makes things a lot easier.  Often the tensioner is an extra wheel which can also help with any wrap problems.

 

N

[magnetman]

A tensioner like one finds on the serpentine / auxiliary belt on vehicle engines. 

 

It would be interesting to design an aluminium plate which would hold the alternator and the tensioner then bolt onto the engine somehow. Laser cut 10mm aluminium plate. 

 

All on one. Could be nice. 

[billh]

On 04/03/2024 at 12:52, Tracy D'arth said:

A bit slow answering.

 

 

Alternators will run happily in reverse with the right fan on if need be, so it could be fitted facing backwards instead of normal.

Link belts mean that you can fit a belt without taking the drive shaft and/or gearbox off.

A bit of a side issue , if I may ask? We have an A 127 alternator  on a slow running engine, V belt running on the flywheel rim, no groove. The alternator runs opposite direction  to "normal", that is anti-clockwise  looked at from  the pulley end and works ok  if a little hot at times. I have yet to find the correct  rotation fan for this, any ideas for a source?  The power demands of the boat are  quite modest.

[Tony Brooks]

21 minutes ago, billh said:

A bit of a side issue , if I may ask? We have an A 127 alternator  on a slow running engine, V belt running on the flywheel rim, no groove. The alternator runs opposite direction  to "normal", that is anti-clockwise  looked at from  the pulley end and works ok  if a little hot at times. I have yet to find the correct  rotation fan for this, any ideas for a source?  The power demands of the boat are  quite modest.

 

Put "anti-clockwise alternator fans UK" into Google and you will find several offers, but make sure the hole for the shaft is the correct size.

 

Edited to add: here is just one https://www.ccw-tools.com/WOSP-LMF003---Lucas-A127-counter-clockwise-alternator-fan__p-180937.aspx

Edited March 9 by Tony Brooks

[Tracy D'arth]

Toothed timing belts would not like a small alternator pulley so you are back where you started. Otherwise they work well.

I would ask Lancashire Rotating Electrics for an alternator that will charge at lower speeds, Its only a question of how many poles the stator is wound with.

 

Incidentally they will have reverse fans or even bi-directional fans available.

[BWM]

I've often wondered if an alternator designed for a lorry may be a better option as most are low revving (limited to 3,000 rpm)?

[Rincewind]

On 08/03/2024 at 23:58, Doodlebug said:

Does anyone know why the need for an alternator to slip? A timing belt would allow for a much tighter and smaller pulley in the alternator and thus could solve my problem. But why do you never see timing belts used in this way?

 

I too looked at this scenario many years ago and questioned why Vee / wedge belts are used in this application.  Having worked for a living on many diesel generation plants of different configurations, I could not arrive at a sensible conclusion other than it was nothing more than a historic and cheap solution to drive the alternator on an ICE.   I.e., wedge belt arrangements can tolerate a little misalignment in several planes without being unduly compromised. (Automotive industry driven I suspect, with one eye on production costs and the other on third party repairs / replacements beyond their control).

 

22 minutes ago, BWM said:

I've often wondered if an alternator designed for a lorry may be a better option as most are low revving (limited to 3,000 rpm)?

Beat me to it! the link below may prove informative. It seems to allude to that application.

 

 As regards your particular engine / alternator setup / problem, you may find this link interesting for Prestolite / Leece-Neville alternators:-

 https://www.idleproextreme.com/wp-content/uploads/2019/03/IdlePro-2pg-Flyer-031819.pdf

 

I also have some technical information that I downloaded from Leece-Neville many years ago in PDF format that I could forward to you if you wish, via email.  It contains info on pulley selection guides, output curves and recommended drive to alternator ratios etc.   

Sadly I can no longer find the link on-line but the PDF Data is still valid.

 

If its of interest to anyone else...........

Disillusioned with the traditional set up of the Vee belt alternator drive, with its many problems, twenty years ago I changed my Vee belt drive to a toothed belt drive system (water pump included).   

I used HTD pulleys and belts (20mm wide x 8mm pitch) using taperlock fittings on the crankshaft and water pump, matching the sizes of pulley diam. as close as possible whilst maintaining the crankshaft to alternator drive ratio.   Due to its small diameter the alternator pulley was bored out to the size of the shaft and counter bored to accommodate the retaining nut.  I retained the tensioning arrangement as that part of the setup is simple yet effective but it did require appropriate spacers in order to establish alignment of the pulleys.

https://bearingtech.co.uk/collections/8m-timing-belts/products/960-8m-50-htd-8m-timing-belt-960mm-long-x-50mm-wide?variant=14242447261741

As far as reliability is concerned I can testify that after twenty years’ service, I have had no problems with the drive train whatsoever.  

As a matter of fact I bought two "spare" HTD belts at the same time all those years ago, - "just in case" - and they are still in the same protective plastic bag in the engine room, untouched and unused to this day.

I checked the belt a few weeks ago, and it shows no visible cracks or deterioration!  (But having said that, Sods law dictates that it will 'give up the ghost' and snap next time I am out cruising!)  

 

Benefits include:-

• No belt slip - hence better generation of power - and positive / reliable water circulation!
• Reduced belt tension - resulting in less stretching / wear of belt. (some tension is required to eliminate "belt slap")
• Less wear on alternator, water pump and crankshaft bearings. (No excessive side loading)
• Positive knowledge of drive condition if electrical generation problems should occur.

 

[agg221]

What happens if you take one of the belts off with the current set-up?

 

We have a slow running engine (Kelvin J2) and a 160A Leece Neville large frame alternator. We are on lead-acid but the starter battery is 900CCA so when you first start charging the current is pretty high, sufficient that the alternator has to be switched out for starting. I don't have a revs problem because there is space for a large pulley on the front of the flywheel, but it is a single V belt and I do not have problems with it slipping. The alternator is bolted to the engine bed separately from the engine unit and tensioning is the standard automotive stick a bar under and lever it back in the slot, then do it up when it's tight on the belt.

 

Your alternator is up against the bulkhead end, so you could afford to come out sideways a bit, under the tank. With that in mind, I think I would be looking at whether you too can get away with a single belt. If so, I would look at increasing the main pulley to the maximum possible size, placing the intermediate pulley where the alternator currently is, with the maximum possible difference between large and small, and then mounting the alternator separately on the floor. I would not expect the flex to be a problem.

 

Tensioners - the standard lever it back and bolt it up approach generally works, but if you want more precision then using the bottle screw approach as applied for example on Myford M lathes is a good option. The occasional lathe gets scrapped with one of these on so it may even be a good source of them.

 

Belts - I currently have several standard V belts of the right size and the first one has held up for three years, so I am not exactly getting through them, but when I do need to buy something I will probably go for a link belt as it makes reassembly much easier. This type: https://store.lathes.co.uk/belts/nu-t-link-v-belt

 

Alec

[Tony Brooks]

5 hours ago, Rincewind said:

I used HTD pulleys and belts (20mm wide x 8mm pitch) using taperlock fittings on the crankshaft and water pump, matching the sizes of pulley diam. as close as possible whilst maintaining the crankshaft to alternator drive ratio.

 

I mention that taperlock pulleys may not be suitable for many engines as the crank shaft oil seal runs on part of the pulley and the water pump pulley is often flange mounted.