Hfl generator issue

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boatingdave

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I've seen various threads re these generators but not a lot of info out there. I have a circa 1995 hfl 6kva built in diesel generator. Sometimes, getting less often, it runs ok. However, most of the time it runs for a few minutes and then does a 'fault' shutdown. It does this even if it is electrically isolated from the boat i.e. all switches off. Bizarrely on occasions if the main engines are running it helps. This may be a red herring but thought it worth the mention. I don't have any further info on the unit and there is some black 'dust' from a rectangular port at the base of the unit if that helps? Anyone have manuals for these generators so I know what to test and what parts need to be changed in a service.
 
PM Me your email address. I completely stripped-down and re-built a HFL 6kVA and had the stator re-wound last year.

After a LOT of trouble I eventually managed to track down a manual which will find invaluable. I can scan and email it.

Basically, once started the control circuit monitors the oil pressure and a temp switch and if one activates, the fuel pump relay drops out and the engine will stop. I have all the schematics with some of my notes on them.
 
John. Many thanks. I now know where I need to look. It could just be it simply needs a service and the checks associated with that may fix this given the symptoms and the cause of the shut down. Now I need to find out where to get the service spares.
Oh and I've also noted it hasn't been used properly according to the manual (now I have a manual) so I'll modify the way I use it once fixed.
Kind regards, assistance appreciated.
Dave
 
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Dave,

No problem, glad to be of assistance. You have just reminded me to start my genny, I am currently on the boat.

You can order parts for the engines from Mitsubishi - I will see if I can dig-out an invoice, as I recall it was quite straight forward, I ordered a complete gasket set.

Anyway, hope all goes well, I am sure you will get it sorted now that you have the HFL and engine manuals.
 
Hi John. Update- Three faults found. Very little coolant water, found a leaking jubilee. The Vee belt was also slack and at the end of its travel but I found a 'used' one which wasn't quite as worn and fitted that. Got all smug, then it got lumpy and kept on stopping so no longer smug. Checked all the filters (or so I thought), blew through all fuel lines etc. Very poor flow from the electric fuel pump, consulted the manual then I found the black crusty fuel filter in the base which didn't look as if it had been checked or changed within the life of the generator! Didn't have a spare but cleaned it as best I could and she is now running. I've made a list of all the bits I need to get to give her a good service. I haven't had the boat long and I suspect the generator has had a poor service history so I'm going to treat her to some tlc when I get the service parts!
 
Yep, I know the filter - its good to find a cheap resolution, not often the case!

The Mitsy engine is a robust and simple little lump, as is the genny in operation, it just uses a self-exciting coil, so if ever it does not seem to be generating, you just need to flash 12v across the winding, its all in the manual. The capacitor then charges and retains its charge for future use.

Under the lid of the control box you may also find a transformer and bridge rectifier, again a very simple charging circuit for a separate starter battery, my genny is started off the domestic bank, so I removed it to free up space under the lid. Once you get to know it, other than routine maintenance, I have found it to be very reliable in operation and it runs both my reverse cycle heat pumps nicely when on the hook.

The problem I had was due to a sea water leak, from the cooling pump, which went unnoticed allowing water to penetrate the genny casing and causing the stator winding to burn out. I had to have the stator re-wound. She has both 120v and 240v tappings. You can easily remove the stator winding leaving the rotor connected to the engine, which I only found out of course after I had removed the engine and gennyin one lump from the engine compartment Grrrrrrr.
 
Having read your post I have a HFL Generator that I have just ordered another capacitor for (No 240v output) but do not have a manual to see how to "Flash" the field. Can you help me out with the procedure for this please?
 
I sent manuals through to Boatingdave: PM me your email address and I will forward them to you - it was a real pain to obtain the info but now I have it, and have completely stripped down and re-built my one I'm happy to help. I also have the manual on the Mitsy engine that drives it.

It really is very easy, just leave the capacitor connected to the winding then flash 12 vdc across it (+ve to one side of the capacitor and -ve to the other). That will provide a small voltage to the excite the coil its connected to, its a closed circuit so the charge holds in future unless the capacitor for some reason discharges. Literally just flash the -ve and +ve.

Always take care when working with capacitors as they can hold a powerful charge. If in any doubt of your own abilities then do have an electrician familiar with this type of equipment undertake the exercise for you.
 
Jetstreamflyer said:
Having read your post I have a HFL Generator that I have just ordered another capacitor for (No 240v output) but do not have a manual to see how to "Flash" the field. Can you help me out with the procedure for this please?
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Flashing the field means inducing a small residual magnetic field into the rotor field by energising the rotor field coil via its brushes. This only needs to be a few volts but you need to try to determine which brush connects to the negative normally, then simply use a 9 volt battery connected to the field for a few seconds, negative to the negative connected side, positive to the other.

If the generator excites at next start up then it has worked. Otherwise apply the flash source with the generator running, but this involves working on the fields of a 240volt generator, so if you are not sure what you are doing DO NOT TRY THIS. Once the generator excites it will produce its own field current source.
 
No almost completely incorrect, with the HFL generator the exciter coil forms a separate winding as is built into the stator, the capacitor is flashed to induce a small voltage in it and due to electro-magnetic induction, induces a field in the rotor coil, there are no brushes or commutators in an HFL generator.

Its a very simple design, trust me, I have had all stator windings re-wound and completely stripped down and re-built one of these generators - information is clear in the manuals and I have sent them to the OP.
 
The method of testing and flashing the capacitor is also that recommended by the OEM HFL as given in their manual, it is quite safe, as long as you follow their instructions, I have done this several times.
 
For those that are interested, I thought I should explain why the HFL method is reasonably safe:

You only need to flash the capacitor when the generator is NOT producing any AC output voltage at its main winding(s)/output terminals, you flash the capacitor with 12 VDC which, under normal operating conditions ensures a 1.5 VDC voltage is retained due to the charge stored in the capacitor/exciter winding, which you can also test with a multi-meter.

After flashing, the field in this separate stator winding is excited, inducing a field in the 'closed loop' rotating rotor winding, which interestingly has diodes in series to ensure the rotor field maintains the correct orientation of magnetic flux poles, then slowly the field voltage builds up inducing a higher voltage and hence current flow in the rotor, this of course builds the output AC voltage in the main windings, until after a while the correct output voltage is achieved.

I do quite like the very simple design, the idea of using no brushes or commutator appeals to me, on the rare occasion the capacitor looses its charge you do need to flash it. I only had to do it when my generator developed a fault, so the charge had lasted for well over 5 years and I suspect will never need to be repeated unless the capacitor for some reason is discharged.

When I had the problem Superheat6k did offer to take a look at this for me, which was kind of him, but in the end I stripped it down myself and just had the stator windings re-wound by Dowding and Mills in Southampton. It also allowed me to fully service the engine/genny.
 
A while ago I spoke to a very nice man from HFL on this number in relation to my generator- 020 8360 1400. His knowledge and information were invaluable.
 
dslittle said:
And I think that the number used to divert through to the horse's mouth in Germany.
Click to expand...

Ahhh that makes sense

One of the real benefits of this Forum IMO is that we have so many Forumites that regularly contribute and are prepared to stick their heads above the parapet, in a sincere attempt to try to help others, long may that continue.
 
I haven't been on for ages. Managed to fix the engine side of the generator but it has developed an electrical problem. Googled it and found my old post! John - sent you a PM but not sure if it got to you. I think I need to flash the capacitor as the output has died so very timely 'drift' in the thread lol.....
 
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