Paguro 3000 genset

[pulsar]

Hi guys, has anyone out there ever seen or heard of this problem with the subject genset before?
Late last summer our Paguro failed to output any AC voltage. The engine started fine and ran as normal, but no AC.
As it was end of season I left it for the spring job list!!!
Well, after 2 weeks of problem determination, tele phone calls and a visit by a marine electrician etc, the problem was discovered.
The rotor was not turning when the engine was running. Bizarre.
With some help I lifted the genset and removed the generator from the engine. (the genset is buried deep in the bowels of an old S&S Swan!!!)
What I saw was truly bizarre. The shaft of the rotor, 30mm steel had completely sheared where it goes into the coupler on the back of the flywheel.
No damage anywhere else. End bearing running free and no sign of damage. The rotor had not even touched the inside of the stator.
Now the genset was installed new in 2007.
I live in Malta and every summer we take the boat to Greece for 5 months cruising. So in that time we have used the genset regularly. To date I have 2700 hrs on the clock.
The genset has not been very reliable since the first season. To date 14 different problems have actually stopped the engine. Fortunately like most cruisers, I am electrically and mechanically minded so am able to fix most problems.
Now we come down to crux of the matter.
The genset was supplied from a dealer in the UK. I contacted them with a view of getting a new rotor.
Parts catalog showed a complete assembly was available, bearing, rotor and coupler. £500 ish shipped to Malta.
That seemed expensive but at least I could get the genset going again.
Then the bad news arrived by email the next day. The manuf had changed the generator and the only rotor they now supplied was for the new generator which was not compatible with my 'old' machine.( 'old ' machine, purchased new and installed in 2007!!!!.) Now the only parts I can get is a complete generator, shipped to Malta direct from Italy for £1800.
So if anybody has come across this problem let me know.
And any Paguro 3000/4000 users....beware of the change in generator.

Pulsar.....

 

[kashurst]

is there enough material left to get the rotor in a lathe and clean up the broken end and bore it out to take an insert/ new extension? other than that a second hand gennie part on ebay?

 

[pulsar]

kashurst,
No the shear is directly across the face of the rotor. I have had it around engineering shops and nobody wants to put it in a lathe.
Have attached some photos.

Pulsar

 

[rustybarge]

is there enough material left to get the rotor in a lathe and clean up the broken end and bore it out to take an insert/ new extension? other than that a second hand gennie part on ebay?

A small gearbox to shaft coupler would probably be the right size, get one end turned down to fit flywheel....

 

[kashurst]

that doesn't look too difficult as the rotor already has a centre bored in it. the w/shop need to first make a cylinder thats a very good fit in that hole (I'm guessing that hole is @ 10mm) with a cone bored in the other end so it can be put in a lathe. I don't think just putting a 10mm ish shaft in there will be strong enough. The bearing end will go in the chuck and the "new extension" will go in a running centre. easy then to clean it up and bore out the rotor around the extension cylinder. the coupling is easy- heat up and knock out the remains of the old shaft. Then make a new extension that fits into the bored out rotor and into the coupler. Either machine in a keyway to lock it all together or make the new extension an interference fit and cool it down in a freezer before pressing it in. Probably worth trueing up the coupler in a lathe too as it may be the cause of the breakage.

I think the original shaft has snapped because it wasn't running true relative to the coupler and bearings putting a load into the shaft that has work hardened it and snapped. If you can't find anyone in malta maybe send it to someone in the UK?

 

[david_bagshaw]

Any method of identifying who made the generator for them?

alternatively, have a new shaft made to mount the squirrel cage rotor on to.

Fletcher bickton in stoke on trent , as electrical motor repairers might have some ideas

 

[david_bagshaw]

your piccs are up now, cut the rotor apart and have it re wound on a new shaft.

hardest bit will be getting the shaft made.

 

[pulsar]

Yes. The generator part of the Paguro 3000 is made in Italy by Volpi Techno Energia. They have already said they dont have the rotor anymore and the new rotor is not compatible with my 6 year old machine.

Pulsar

 

[rustybarge]

Yes. The generator part of the Paguro 3000 is made in Italy by Volpi Techno Energia. They have already said they dont have the rotor anymore and the new rotor is not compatible with my 6 year old machine.

Pulsar

there is very little power going through the shaft on a 3kw genny. As already stated it was probably vibration that caused the sheared shaft.

Imho you can repair this shaft quite easily.

Drift out the old shaft in the rotor about 1 inch
make a guide sprigot to align the two pieces of the old shaft exactly using the small center hole
grind a slot around the shaft with an angle grinder to accept a weld
weld and drift shaft back into rotor

.....should be good enough, if there's a vibration problem welds a couple of nuts onto one side of shaft to counterbalance.

welcome to the world of farm machinery repair!!!!

 

[Latestarter1]

there is very little power going through the shaft on a 3kw genny. As already stated it was probably vibration that caused the sheared shaft.

Imho you can repair this shaft quite easily.

Drift out the old shaft in the rotor about 1 inch
make a guide sprigot to align the two pieces of the old shaft exactly using the small center hole
grind a slot around the shaft with an angle grinder to accept a weld
weld and drift shaft back into rotor

.....should be good enough, if there's a vibration problem welds a couple of nuts onto one side of shaft to counterbalance.

welcome to the world of farm machinery repair!!!!

In theory anything can be fixed, however time to cut ones losses. A couple of years ago I suggested that this Italian stuff was junk and advised sticking to market leading U.S. sets, hate mail lasted for weeks!

Single bearing alternators of this type require very small tolerances on alignment, and the foundation/support system must be very stiff to prevent excessive vibration from damaging the unit. Single-bearing units are also somewhat limited in size, as the hard coupling and the bearing on the driver would have to be pretty massive to support half the alternator. Unless these type of alternator is from a quality manufacturer they can be a complete money pit.