Hfl diesel generator advice

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John100156

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As some of you may know, I had problems with my HFL H2W6M1C 6kVA diesel generator last year, so I have returned it to the UK to service and repair it as a winter project.

I want to split the generator section from the Mitsubishi L2E engine, I know how to check the diodes once I can find/get at them, but I think I have a winding down so wanted to strip down the generator.

I have asked many times for advice from HFL: hfl@hfl-hattingen.de but they take ages to respond and when they do, I must say that they have not been very helpful at all.So...

Does anyone know of a reputable HFL generator repairer or motor re-winder they could recommend? I would like to service the engine and strip the generator down myself but would consider dropping it into a reputable repairer - ANY advice would be most welcome!

 
Worth a quick email to boats.co.uk. Last year they had a genset leftover because they put a bigger one in a stock boat that had aircon retrofitted. My brother bought it at a great price (an Onan 9kva, with <1 hour on it)

Another alternative is to buy a horrid generator for land use from ebay and keep the alternator but chuck away the engine and frame. You'll only have to make a connecting flange to put the alternator on your engine
 
Certainly some food for thought there John, thanks - there is an 8kVA HFL floating around (not literally, like my one was....) but it would not fit in the engine compartment where the existing unit goes, sigh.

TBH the L2E engine is in good condition and the HFL unit works very well and fits neatly into the boat, I would really enjoy stripping it down, I was an electrical engineer before moving to the dizzy heights of consultant many moons ago and also rebuilt engines as a hobby (rally driver!)

I recall we use to use 'Dowding and Mills'(?) to rewind motors in the old days, once I get the diodes out of the way I can Megga the windings once I can get them, to see which one(s) down then seek to get it re-wound - best laid plans, always works out cheaper in the long run to buy a new one I know, ever the optimist!

So chaps, still up for recommendations for HFL service agents in the UK or a good motor rewinder.....
 
If you can get it to our workshop in Kirkby in Ashfield happy to have a look and see if we can rewind it (ideally just the alternator or stator).

Most our stuff is larger 3 phase motors, but our winding man has seen most things in his time.
 
Trevor many thanks, that's kind of you.

Ross that's useful, I will certainly give them a call on Monday.

I managed to get the engine and genny onto the bench yesterday and hope to start stripping it down later today, will start with trying to find where the diodes are hidden!
 
Well, I now know why the generator was not working properly, not a good sign when you remove the end cover to find water leaking out and the following...... don't reckon a spray of WD40 will fix this one!

IMG_6631_zpsy3r9qv4j.jpg


Hope to release/separate the generator this week, assume you release the casing bolts and stator will draw back around the rotor. Then I should be able to see how the rotor connects to the crankshaft,,,,,
 
Not sure it was a water cooling/jacket problem, if that's what you're implying, I can pressure-test that (soon) to check, but once the pump was repaired the bilges remained dry so don't think that's an issue; original fault was a leak from the sea water pump gland that filled the compartment (spill-over to bilge pump in adjacent compartment too high) leaving the generator casing immersed in sea-water for weeks until we arrived at the boat, It must have penetrated the casing. I left it for ages to dry-out, but clearly no long enough before starting the generator which probably led to the demise of the stator winding.
 
John100156 said:
Well, I now know why the generator was not working properly, not a good sign when you remove the end cover to find water leaking out and the following...... don't reckon a spray of WD40 will fix this one!

IMG_6631_zpsy3r9qv4j.jpg


Hope to release/separate the generator this week, assume you release the casing bolts and stator will draw back around the rotor. Then I should be able to see how the rotor connects to the crankshaft,,,,,
Click to expand...

On some generators the end plate acts as a seal to the waterways inside the genny end , the gaskets and bearings are a service item especially on the Fischer panda sets. Looking at yours the casing could be water cooled, if it's sea water cooled then it looks like it's corroded hence the water leaks into it and the build up of salty deposits, I'd suggest you try and get it rewound otherwise it's shopping for a new genset. I have just bought a small Fisher panda set with the dreaded farryman engine but it's one of the upmarket ones in that it has a heat exchanger with a closed cooled circuit. Will be checking it over with the intention of fitting it yo my own boat in the near future. As per most gensets they sit there untouched until this happens then it's way too late. All down to poor design I still can't believe that manufacturers assume sea water and alloy or cast will last, they simply don't.
 
volvopaul said:
On some generators the end plate acts as a seal to the waterways inside the genny end , the gaskets and bearings are a service item especially on the Fischer panda sets. Looking at yours the casing could be water cooled, if it's sea water cooled then it looks like it's corroded hence the water leaks into it and the build up of salty deposits, I'd suggest you try and get it rewound otherwise it's shopping for a new genset. I have just bought a small Fisher panda set with the dreaded farryman engine but it's one of the upmarket ones in that it has a heat exchanger with a closed cooled circuit. Will be checking it over with the intention of fitting it yo my own boat in the near future. As per most gensets they sit there untouched until this happens then it's way too late. All down to poor design I still can't believe that manufacturers assume sea water and alloy or cast will last, they simply don't.
Click to expand...

Yes, the genny jacket is cooled: sea-water enters via a standard filtered sea-cock, through a belt driven pump, into and out of the genny casing then passes through the engine oil-cooler and engine coolant heat exchangers out through the exhaust elbow.

There is no gasket to the end cover (I thought there would be) it is a close-fit, I expect some blue Hylomer might be all that's required, no sealant visible though.

I am not sure water leaked from the jacket, but I will pressure test to make sure, which is a simple thing to do. The problem was sea-water ingress due to immersion over time.

The armature looks OK and there does not appear to be any contact so assuming its simply the stator windings that shorted-out I reckon its definitely worth re-winding - at this stage! The Engine is a Mitsubishi L2E diesel which seems pretty simple and robust.

I do agree though the design as a whole is not great, yet when operating it worked really well. The close proximity of a large rubber HX hose to the impeller cover is very poor. You also need to remove the HX to remove one of the bell housing bolts. I may have a go at splitting the genny casing from the engine/bell housing tomorrow. I would like to know how the armature connects to the crankshaft, or flywheel, I assume it might be some form of splined shaft as it does not require a clutch but I'm only guessing.
 
OK So for those that are interested, progress so far:
Generator_Page_1_zpsv1ufhizg.jpg


Top Row
Left - genny end-casing – relatively easy to remove novisible signs of gasket
Mid - armature no signs of damage or contact with stator
Right – no obvious grub screws so must be splined to shaft –not sure how to remove probably puller

Mid Row
Left - stator casing lots of debris no signs of cooling jacketleak – Yet!
Mid - armature with what appears to be diodes to north andsouth poles
Right – no brushes or commutators visible, self-excited, assumeby electro-magnetic induction

Bottom Row
Left - stator casing appears sound but needs thorough cleaningno sign of contact
Mid – clear shot of diode not sure if there is one at otherend of each coil yet
Right – as above

Next steps
1. Thorough clean-up
2. Test the diodes - I reckon I will need to de-solder oneend before I megga each coil
3. If all good then will probably not split from flywheeland crankshaft
4. Pressure test water jacket – probably go to say 5 Bar
5. Speak to contacts to have stator re-wound
6. Whilst waiting fully service the engine and paintblock/ancillaries
7. Re-assemble
8. Ask SWMBO to start engine whilst hiding behind a hardbarrier

Any suggestions/observations welcome – will take a while asI’m busy at work but thoroughly enjoying the challenge.
 
The nut at the end of the bearing is attached to a long threaded stud that goes into the crankshaft or flywheel , this tightens the rotor on to a taper, undo the nut and you may be lucky it falls away from the flywheel.
 
The stator looks fairly simple to rewind. Please PM me if you want us to look at it in our factory, but there would be some cost for a rewind, based upon time and materials, but not a look and see.

For the rotor I would avoid meggering as it does not operate at high voltage, and this could avoid need to disturb the diodes. I would immerse it in warm fresh water for a few hours changing the water a few times, then blow dry it with a normal hairdryer to remove as much loose water as possible, then bake in the oven for 3 - 4 hours at just below 100oC. The insulations will be good for at least 140oC.

This will get any salt out of what otherwise looks like a decent rotor.

Once this is done measure the winding resistances with a decent low ohm meter, such as the ohms setting of a Megger (not the 250 500 or 1000v settings).
 
volvopaul said:
The nut at the end of the bearing is attached to a long threaded stud that goes into the crankshaft or flywheel , this tightens the rotor on to a taper, undo the nut and you may be lucky it falls away from the flywheel.
Click to expand...

Paul, I had to remove the long bolt to remove the end-plate, it's only inserted hand tight to avoid loss. I was thinking of undoing the flywheel bolts, you can get in between the impeller and flywheel. Not sure though if its splined in to the flywheel or crankshaft itself, I expect it is. Was also wondering if after removing the long bolt you might be able to insert a tool and pull it off - I will investigate further. If it cleans and tests OK, I may just leave as-is, no obvious play in the bearings, given the hours run they should be in good order.....
 
superheat6k said:
The stator looks fairly simple to rewind. Please PM me if you want us to look at it in our factory, but there would be some cost for a rewind, based upon time and materials, but not a look and see.

For the rotor I would avoid meggering as it does not operate at high voltage, and this could avoid need to disturb the diodes. I would immerse it in warm fresh water for a few hours changing the water a few times, then blow dry it with a normal hairdryer to remove as much loose water as possible, then bake in the oven for 3 - 4 hours at just below 100oC. The insulations will be good for at least 140oC.

This will get any salt out of what otherwise looks like a decent rotor.

Once this is done measure the winding resistances with a decent low ohm meter, such as the ohms setting of a Megger (not the 250 500 or 1000v settings).
Click to expand...

Thanks Trevor, let me see how the tests go and things develop, I may well need to take advantage of your kind offer. I will PM you in due course.

Thanks also for rotor advice, which makes sense, the rotor does not appear to have suffered any obvious sea-water ingress/damage, which mainly affected the lower part of the stator; no doubt some must have got circulated when attempting to re-start, I did leave it for many days to dry-out when on the boat, but some clearly entered, so a good wash and thorough dry makes a lot of sense.

Although voltage is high when megga'ing I suspect the current is very low, so conductors should be OK, albeit I know the HV will of course impact/breakdown the insulation, in essence that's why we use it, but I may do as you suggest and just test the resistance/continuity with a good meter and if no obvious deviation from manufacturers info (which I do have) I may not disturb the diodes or megga.

Thanks to all for taking the time to comment and advise - very much appreciated.
 
John100156 said:
Thanks Trevor, let me see how the tests go and things develop, I may well need to take advantage of your kind offer. I will PM you in due course.

Thanks also for rotor advice, which makes sense, the rotor does not appear to have suffered any obvious sea-water ingress/damage, which mainly affected the lower part of the stator; no doubt some must have got circulated when attempting to re-start, I did leave it for many days to dry-out when on the boat, but some clearly entered, so a good wash and thorough dry makes a lot of sense.

Although voltage is high when megga'ing I suspect the current is very low, so conductors should be OK, albeit I know the HV will of course impact/breakdown the insulation, in essence that's why we use it, but I may do as you suggest and just test the resistance/continuity with a good meter and if no obvious deviation from manufacturers info (which I do have) I may not disturb the diodes or megga.

Thanks to all for taking the time to comment and advise - very much appreciated.
Click to expand...
The issue with meggering a low voltage coil with contaminants is the possibility the megger actually creates leakage tracks, and the diodes won't like it up them. If you do megger then keep it to its 250v setting.
 
Yes, I quite understand what you are saying.

HFL In their manual state that if the equipment has been stored, or gets wet....., the insulation resistance of the windings should be checked and they recommend that this is done between the rotor winding and the rotor core using a 500v megger. They further recommend the diode(s) are removed first. They expect at least one mega ohms of course.

What I found interesting, was that if the resistance is less than that, they recommend the rotor be dried out first or, and this is the interesting bit, by passing a current from a low voltage source through the winding, I suppose you could start with a low voltage and low current regulated through a variable resistor and monitor winding temp, which seems sensible and very easy to set-up. Busy this week but may try this over the weekend.....

They give the rotor winding resistance at 3.7 ohms, main stator (entire winding) resistance given at 0.3 ohms and auxiliary winding at 3.9 ohms.

The winding insulation class is: H
 
Well, at last, having stripped down the Mitsy diesel engine and HFL generator and having worked out the winding configuration (the generator is self excited using an auxiliary winding positioned at an angle to the two power windings and loaded by a 35uF capacitor, you just flash 12vdc across the capacitor for one second to load it, if for any reason the capacitor has become discharged). What threw me for a while was three additional cables derived from the generator, they turned out to be different tappings to the auxiliary winding (11 cables originated from the generator casing in all) which when stripped-down were not connected to anything. Only 8 cables need to be used, the two stator windings had 110v and 230v tappings so 1-2-3 and 4-5-6 and two to the auxiliary winding numbered 5 and 8, probably should have changed the 5 to a 7....

Anyway, I managed to get the stator re-wound in Southampton and having mocked-up some switches and a relay to mimic the controls on the boat, I ran-tested her on Thursday, just in time to deliver to a friend on Friday, morning to take back to Sant Carles (Thanks Peter).

No time to paint her to make her look pretty, I can do that out there and fit new hoses/clips when re-installing, I expected some teething problems, but instead, she started first time as she always did with no problem at all and worked very well. I loaded her and left her running for some time: here she goes:

Thanks to all those that have offered help and advice - much appreciated as always.
 
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