Alternator Left or Right Handed ?

[Alan de Enfield]

Right then - If I intend to keep a 'spare' I need a "right hand" alternator (fixing points on the right hand side of the alternator when viewed from the front), with correct rotation and staying at about 55 amps.

 

Looked on ebay and found several that appear to do the job - but - the one fitted at the moment has a wire coming out of the regulator, non of the ones I've seen anywhere have this. Is this something peculiar 'boaty' or 'Lister engined' or does it not do anything, would I need to drill a hole in the new one and fit it ?

 

Advice please

 

[Keeping Up]

That's the connection for an external controller such as a Kestrel, Adverc, Sterling, or similar.

 

If you have a controller and want the connection, most eBay suppliers can fit it for you at nominal cost. If you don't have a controller you can ignore it - but query where the wire goes to at the moment. Ditto if you have a controller but don't want to use one in the future.

[BEngo]

That looks to me more like a tractor regulator with temperature sensor wire than a modded for controller regulator extra wire, simply because of the route it takes into the controller. Could be wrong though.

 

As Allan says- where does it go at the moment?

 

N

[Alan de Enfield]

Yes I've got Sterling Battery Isolators. Adverc controllers and several other unknown boxes with wires coming out & going in.

 

I'd prefer to keep things the same as they work - whats the best way to get an alternator wired up with a short 'fly lead'to connect into the system ?

 

Thanks

Alan

[Keeping Up]

If you've got an Adverc, on its standard cabling there should be a green wire from it to the alternator's regulator. If you buy your alternator with a connection already made to the regulator inside, and brought out on a flying lead as your photo appears to show, then assuming that all the other connections have remained undisturbed it should all work. I would see if you can trace the existing wire first though because as BEngo says it could alternatively be a temperature sensor although if you have an Adverc at the moment it's my surmise that you'll find the wire goes to it. You can download the installation instructions from their website.

[Alan de Enfield]

I'll try and follow the wiring but it dissapears into the harness - I guess its all connected as I have an orange "Adverc High Voltage" warning light on my panel (above and to the right of the ignition switch and other panel lights)

 

[Keeping Up]

I'll try and follow the wiring but it dissapears into the harness - I guess its all connected as I have an orange "Adverc High Voltage" warning light on my panel (above and to the right of the ignition switch and other panel lights)

 

 

 

That would usually leave the Adverc as a yellow wire - but it is entirely optional.

[ditchcrawler]

Yes I've got Sterling Battery Isolators. Adverc controllers and several other unknown boxes with wires coming out & going in.

 

I'd prefer to keep things the same as they work - whats the best way to get an alternator wired up with a short 'fly lead'to connect into the system ?

 

Thanks

Alan

Adverc come in positive or negative versions depending on how the regulator in the alternator is wired, so you need to buy an alternator that has its regulator fitted the same as the one you have. There should be a sticker on the Adverc unit saying which it is, mine is 24 neg as its a 24 volt unit.

 

That would usually leave the Adverc as a yellow wire - but it is entirely optional.

From the details I have here yellow is over voltage alarm and green is field.

 

Edd. Sorry Keeping Up I completely miss read your post and you are of course correct.

Edited March 1, 2014 by ditchcrawler

[Keeping Up]

Adverc come in positive or negative versions depending on how the regulator in the alternator is wired, so you need to buy an alternator that has its regulator fitted the same as the one you have. There should be a sticker on the Adverc unit saying which it is, mine is 24 neg as its a 24 volt unit.

 

From the details I have here yellow is over voltage alarm and green is field.

 

 

Edd. Sorry Keeping Up I completely miss read your post and you are of course correct.

No problem!

 

Good point about the positive and negative varieties of Adverc. According to my Adverc leaflet the Motorola and Valeo alternators need a positive Adverc but almost everything else including the ubiquitous Lucas and its clones need a negative one. Adverc will also change one type into the other for a nominal charge unless you are very unlucky and have a very very old Adverc when you change out your old Motorola for an A127 (guess how I know).

[jetzi]

Pardon the revival of an old thread but after reading this through three times I'm still not sure whether my alternator is right handed or left handed and I think it would be helpful for anyone doing a future search!

My alternator is mounted on the starboard side. The pulley rotates clockwise, if you are facing the end with the pulley on it (same as the engine).

 

Here's a diagram, facing astern.

 

 

I asked Beta and they just gave me part numbers:

Starter      600-02781      40A         £159

Domestic 200-99970        14V 70A  £133

Bando SPZ950 Belt 600-94280/01 £22.50

A40 Domestic Belt  214-99222  £12.50

 

However I plan to buy a cheap 75A alternator from eBay (50 GBP including free postage) because it's a spare that I'm doing some experimentation on.

 

I know that @Sir Nibble is the alternator expert - I wonder if he could give the definitive answer!

Edited November 30, 2020 by ivan&alice

[Tony Brooks]

4 minutes ago, ivan&alice said:

Pardon the revival of an old thread but after reading this through three times I'm still not sure whether my alternator is right handed or left handed and I think it would be helpful for anyone doing a future search!

My alternator is mounted on the starboard side. The pulley rotates clockwise, if you are facing the end with the pulley on it (same as the engine).

 

Here's a diagram, facing astern.

 

 

I asked Beta and they just gave me part numbers:

Starter      600-02781      40A         £159

Domestic 200-99970        14V 70A  £133

Bando SPZ950 Belt 600-94280/01 £22.50

A40 Domestic Belt  214-99222  £12.50

 

However I plan to buy a cheap 75A alternator from eBay (50 GBP including free postage) because it's a spare that I'm doing some experimentation on.

 

Alternators will charge equally whichever way they turn so the hand refers to the mounting brackets. That is which side of the alternator the brackets are. Some are not handed. What you do have to watch re direction of rotation is if the FAN is handed. many are not but if the blades are set at an angle to the radius its a handed fan and it must turn in the direction that lets the outer edge of the blades trail.

 

Someone will be along to explain the "hand" because I simply replace like with like s don't know the details.

[Tracy D'arth]

Its tricky.

The hand refers to the arrangement of the mountings rather than the direction of rotation. Most A127 type have 2 mounts on the fan end and one on the rear.

 

If the alternator is on the starboard side of the engine with the 2 mountings that are inline fore and aft, that it swivels on, on the top and the single front mounting on the bottom with the adjustable bar on it, then it is a right hand mounting.

 

So if the adjusting bar was on the top it would have to be a left hand.      See these illustrations,      

https://www.ebay.co.uk/b/Car-Alternators-Parts/61513/bn_877449

 

Some are made with 3 mountings on the fan end and will mount either right or left handed.

 

 

Rotation does not matter for generation but the fan must suck air in from the rear to cool the electronics and discharge from behind the pulley.

 

 

Edited November 30, 2020 by Tracy D'arth
added

[Tony Brooks]

The link shows a handed fan.

 

it also shows a standard a127 and as long as you are happy to drill a mounting thread out and use a nut and set screw they can usually be converted by removing the through bolts that hold the three body parts together and the carefully rotate the drive pulley) end bracket so the mounting point is on the other side. You will have to drill the adjuster thread out because it becomes a mounting point.

 

This won't work if it has four through  bolts

Edited November 30, 2020 by Tony Brooks

[Alan de Enfield]

My alternators are 'amphibious' (they work on water or land), otherwise known as 'ambidextrous'.

 

The mountings enable mounting on either side of the engine and the 'fins' are straight so ar not handed.

 

Cargo 70 amp, part number 112237

 

 

 

 

Edited November 30, 2020 by Alan de Enfield

[jetzi]

Gosh I still can't say I understand. I do understand now that the handedness refers to the mounting bracket rather than the direction of spin - but do both handed alternator fans spin the same way? That seems like it would be a problem for someone somewhere along the line.

 

The link I sent has an external fan that clearly needs to spin the correct way (because the fins are shaped like little buckets...). It looks from the picture that both the right hand version and the left hand version need to spin anticlockwise to drive the fan. I assumed they'd lazily re-used the pictures for one handedness for both (but obviously I don't know which one).

 

I also can't picture any way I could turn the fan around, so I do think I need to get the right one. But if the handedness doesn't refer to the direction of rotation, then how do I know if either of these will spin the right way?

 

I'm not so concerned about the mounting of it, at the moment my alternator has a spacer and a clearly DIY bracket made out of flat steel bar, so I am not expecting it to fit perfectly. The alternator I have is not original and I have no idea what it is, nor has anyone been able to identify from the pictures, otherwise I would have just considered buying another of the same!

 

I'm planning on trying to modify the regulator to charge my lithium batteries and there's a high probability that I mess it up, so I don't really want to buy a "real" Beta alternator for 3 times the price. That said, charging lithium batteries can get the alternator really really hot so it's important that the fan is doing its job!

 

Here is another diagram showing the mounting brackets. The alternator has two - one at the bottom that pivots and one at the top that is just a slotted bar. I don't have the fancy threaded rod that @Alan de Enfield shows in his pictures

Edited November 30, 2020 by ivan&alice

[Tracy D'arth]

4 minutes ago, ivan&alice said:

Gosh I still can't say I understand. I do understand now that the handedness refers to the mounting bracket rather than the

 

The link I sent has an external fan that clearly needs to spin the correct way (because the fins are shaped like little buckets...). It looks from the picture that both the right hand version and the left hand version need to spin anticlockwise to drive the fan. I assumed they'd lazily re-used the pictures for one handedness for both (but obviously I don't know which one).

 

I also can't picture any way I could turn the fan around, so I do think I need to get the right one. But if the handedness doesn't refer to the direction of rotation, then how do I know if either of these will spin the right way?

 

I'm not so concerned about the mounting of it, at the moment my alternator has a spacer and a clearly DIY bracket made out of flat steel bar, so I am not expecting it to fit perfectly. The alternator I have is not original and I have no idea what it is, nor has anyone been able to identify from the pictures, otherwise I would have just considered buying another of the same!

 

I'm planning on trying to modify the regulator to charge my lithium batteries and there's a high probability that I mess it up, so I don't really want to buy a "real" Beta alternator for 3 times the price. That said, charging lithium batteries can get the alternator really really hot so it's important that the fan is doing its job!

 

Here is another diagram showing the mounting brackets. The alternator has two - one at the bottom that pivots and one at the top that is just a slotted bar. I don't have the fancy threaded rod that @Alan de Enfield shows in his pictures

This drawing shows a left handed alternator.

[Alan de Enfield]

6 minutes ago, ivan&alice said:

Gosh I still can't say I understand. I do understand now that the handedness refers to the mounting bracket rather than the direction of spin - but do both handed alternator fans spin the same way? That seems like it would be a problem for someone somewhere along the line.

Just ask for the specification sheet for the alternator you are looking at :

 

It will have a 'rotation' section mine is 'Bi-Directional' try and find one the same.

 

Spec	Value
Item number	66021126
Sales number	N/A
Series number	AS123
Notes	D+, ONE GROOVE PULLEY New, Euro plug connector Fix circle (Mount): 89mm Fix circle (Adjuster): 82.5mm Bracket angle: -30° / 0° / 30° Cut in speed: 1200, Max speed: 15000 Weight: 5.1kg
System voltage	12
Output	70
Mounting style	SWUNG
Dimensions in	MILLIMETERS
Rotation	BI-DIRECTIONAL
Housing coating	RAW
UL Approved	No
Mounting holes	3
Positive stud size	M6
Negative stud size	M5
Rectifier location
Shaft diameter
Excitation type
Regulator location
Regulator number
Diode trio	No
Pulley included	Yes
Lamp driver	No
Adjustable regulator	No
Remote sense	No
Smart check	No
Batteryless	No

 

[jetzi]

10 minutes ago, Tracy D'arth said:

This drawing shows a left handed alternator.

And a left handed alternator will have a fan that spins clockwise?

 

7 minutes ago, Alan de Enfield said:

Just ask for the specification sheet for the alternator you are looking at :

 

It will have a 'rotation' section mine is 'Bi-Directional' try and find one the same.

The alternator I'm looking at comes in a right hand or a left hand version, and I'm keen on that one because it's really cheap and I will be doing bad things to it.

 

I'm tempted to just buy the left hand and hope for the best... can return it if it is wrong.

[bizzard]

41 minutes ago, ivan&alice said:

And a left handed alternator will have a fan that spins clockwise?

 

The alternator I'm looking at comes in a right hand or a left hand version, and I'm keen on that one because it's really cheap and I will be doing bad things to it.

 

I'm tempted to just buy the left hand and hope for the best... can return it if it is wrong.

If you write ''Alternator fan rotation'' in the search box stacks of imformation comes up including my explanation too.

[bizzard]

14 minutes ago, bizzard said:

If you write ''Alternator fan rotation'' in the search box stacks of imformation comes up including my explanation too.

A clockwise rotating fan is called left handed. 

[Tony Brooks]

9 hours ago, ivan&alice said:

And a left handed alternator will have a fan that spins clockwise?

 

The alternator I'm looking at comes in a right hand or a left hand version, and I'm keen on that one because it's really cheap and I will be doing bad things to it.

 

I'm tempted to just buy the left hand and hope for the best... can return it if it is wrong.

As far as I can see from your latest diagram and your original link the alternator should fit your engine.

 

The fan on alternators SUCK air through the alternator from back to front and I think that you think it blows air. The buckets as you call then need to trail the DoR so the illustrated alternator needs to turn clockwise looking at the pulley end.

 

To save confusing yourself and others please leave left and right hand to refer to the mountings and use clockwise & anticlockwise plus direction of view to refer to the rotation.

 

In any case the illustration in the link shows three through bolts and I have explained how to alter the hand of the brackets.

 

[nicknorman]

Just be clear, fans do suck air through the alternator and eject it at the fan, however the fan is a centrifugal one so if it is rotated the wrong way it will still suck air through, but not as well as it would do if it was rotated correctly. And then there are bidirectional fans that have flat blades.

 

Although I have no proof, it seems obvious that a handed fan rotating in the correct direction will move more air than a bidierctional fan - otherwise, why bother with “handing” fans? Bearing in mind the overheating issues with charging lithium batteries I would therefore suggest that you should try to get an alternator with a handed fan and of course handed the right way for the rotational direction.

[Tracy D'arth]

The direction of proper rotation of the fan is not related to the handing of the mountings, they are 2 separate parameters.

You need a left handed mounting with a clockwise fan which will have its outer edge blades trailing when rotating clockwise.

[Tony Brooks]

13 minutes ago, nicknorman said:

Just be clear, fans do suck air through the alternator and eject it at the fan, however the fan is a centrifugal one so if it is rotated the wrong way it will still suck air through, but not as well as it would do if it was rotated correctly. And then there are bidirectional fans that have flat blades.

 

Although I have no proof, it seems obvious that a handed fan rotating in the correct direction will move more air than a bidierctional fan - otherwise, why bother with “handing” fans? Bearing in mind the overheating issues with charging lithium batteries I would therefore suggest that you should try to get an alternator with a handed fan and of course handed the right way for the rotational direction.

 

FWIW I know of small air cooled Listers that rotate the alternator the opposite way to most that have burned the alternators out when fitted with the opposite rotating fan. I suspect they all had shot LA batteries but that is exactly what good lithiums would look like to the alternator.

 

I want to emphasise the importance of @nicknorman's points.

[jetzi]

13 hours ago, bizzard said:

If you write ''Alternator fan rotation'' in the search box stacks of imformation comes up including my explanation too.

 A clockwise rotating fan is called left handed. 

I did also read this thread:
 

 

And I was still unsure. I think that the fact that I commented on a 6 year old thread should show that I tried to find the information before asking!

 

5 hours ago, Tony Brooks said:

The fan on alternators SUCK air through the alternator from back to front and I think that you think it blows air. The buckets as you call then need to trail the DoR so the illustrated alternator needs to turn clockwise looking at the pulley end.

Yes, I did indeed think that the fan blows rather than sucks! Thanks for the clarification - that helps a lot. I'm surprised though, sucking seems like an altogether less efficient way of moving air, but I must be wrong about that! So, the "buckets" move "backwards" (i.e. convex end first). That makes me understand a lot better - so clockwise rotation (facing the pulley end) is correct for a fan like these:

 

  

I'm sorry that it took so long to hammer into my skull but I do appreciate your patience and I think what some might not fully appreciate is that it's not always clear to a novice things like which is the "front" and which is the "back" of an alternator. Similarly which is the left and right of an engine? If you are looking at the "front" then the "left" of the engine is actually the "right" of the boat. And yes, I assumed that fans blow rather than suck.

 

 

3 hours ago, nicknorman said:

it seems obvious that a handed fan rotating in the correct direction will move more air than a bidierctional fan - otherwise, why bother with “handing” fans? Bearing in mind the overheating issues with charging lithium batteries I would therefore suggest that you should try to get an alternator with a handed fan and of course handed the right way for the rotational direction.

This seems eminently sensible, thank you Nick! Happily the cheap one that I want to buy has a handed fan and I'm planning on blowing some extra ducted air at it as well for good measure - glad I now know to blow it at the coils rather than the fan! To be honest I give this alternator a 50/50 chance of surviving my meddling so I just really wanted to not spend too much money. 

 

---

So for the benefit of any future searchers, what I've learned is:

* Clockwise rotation is usual for alternators (I suppose that if you have an engine that rotates anticlockwise you must buy a bi-directional fan?)
* Handedness of an alternator refers to the side that the mounting points are on. Left hand means that the alternator mounts on the left side of the engine if you are facing the pulley end (this is probably the right (starboard) side of the boat).

* Both left hand and right hand alternators will usually have clockwise-rotating fans

* Fans suck, not blow, air through the alternator and, with centrifugal type fans, you want the concave side to be the trailing side to the direction of rotation.