generator repair

[bwservices]

I have the exact same 22kw single phase version with a perkins 3.152 - which has also got a failed winding in the same place. We are still unsure what to do with it, only got about 550hrs on it, engine is mint.

I think this has exactly the same hrs.less than 600 iirc

 

[Matrixx]

You can get them rewound, but it is usally not cost efective.

 

[Matrixx]

I don't where to start with all that so ill just ignore it

Just saying that is what will be potentially damaged by the fault in the windings, the generator control module will cost less then it would cost to by a new cabinet, no brainer realy.

 

[bwservices]

I have the exact same 22kw single phase version with a perkins 3.152 - which has also got a failed winding in the same place. We are still unsure what to do with it, only got about 550hrs on it, engine is mint.

Made a mistake there.thinking about another unit i have.
This has 1100hrs,still in good nick

 

[the snooper]

You will also have to replace the diode pack, varistor, AVR, exicter pack , just not viable. at the moment the whole rotor is supported be the DE bearing.
the panel will be scrap as well the cabeling insulation will be starting to fail, and the componets are obselete. unless you are doing a restoration?

Don't see why he will have to replace anything on the rotor if it hasn't failed, he has stated the bearings will be replaced, and some alternators you have to leave the rotor suspended like that as it's the only way to dismantle them.

 

[Seadog]

'If it were made by man, man can repair it' - at least that's my philosophy

Mine too, Andrew. And I'm sure it's true of many on this forum

 

[Rig Pig]

The usual killer of standby generators is damp in the windings, our standby units have built in heaters to keep them dry.

 

[Matrixx]

Don't see why he will have to replace anything on the rotor if it hasn't failed, he has stated the bearings will be replaced, and some alternators you have to leave the rotor suspended like that as it's the only way to dismantle them.

You unbolt the alternator from the flywheel first , half the alternator is still connected to the engine, all that has done is take the rear housing off, it is a 2 bearing machine. on a single bearing machine if you put the full weight of the rotor on the rear bearing it will cause damage to the bearing, in the picture the Drive end bearing has the whole weight on it, it must not be like this.

If you rewind the stator then you should realy overhaul the whole alternator, the damage is more than likley casued by the insulation breaking down , corrosion, or green verdigris. as the rotor is the same age it will also be in a poor state, as will all the other components.
in a heavy fault there are a few sacrificial components that will be taken out, the varistor will normall blow up, and some for the freewheeling diodes will blow, the AVR circuit board is hand populated and the soldering will be very week, the electronic components like capacitors will have gone dry.

a new controler will replace all the meters, timers, relays, pushbuttons etc and there under £100. if you have unlimited time and no overheads then it could be an option.
I do this for a living, generators tend to be for standby applications so when the lights go out you dont want an unreliable machine , old components are points of failure.

 

[bwservices]

i could pick that apart bit by bit,but I don't think it would do any good?

 

[julianf]

It would be interesting for the rest of us though.

Again, I have no knowledge about this stuff, but watching a (friendly) chat would let me learn some stuff.

 

[bwservices]

The generator control panel is working 100%
every relay,meter and switch is functioning correctly.
the wiring and insulation is perfect.well,it would want to be,or else every 35 year house in the world would be about to ignite.
a newer generator control unit is of no use to me. a good one will cost a lot more than £100. I have replaced lots of Chinese ones,though.
the rotor has had its insulation resistance checked
the exciter has been checked,diodes tested
the grease bearings are being replaced with sealed items.if anyone thinks catastrophic damage has been done the way I disassembled it,they are entitled to their opinion.
the avr is functioning, adjusting voltage,which is as far as I can go for now. how it regulates under load I will find out when the stator is finished.
repair cost/servicing of an old avr is very little,even compared to modern mass produced Mecc Alte equivalents
I have a choice of modern avrs sitting on the shelf, new, if I need one. I will be comparing new to old, at a later date, just out of interest
its not my first rodeo.
I know what the repair cost will be,give or take 10-20%.its evident from the photos,but this is a pretty basic alternator. 4 terminal 415v. it is a lot cheaper to rewind a stator of this type, compared to a 300 amp Genset or Mosa with 10-13kva. they have 400v ,230v,110v,12v,and welding voltages all coming from different points.a nightmare for a winder.so kva is not the only indicator to cost.
I know what a complete alternator will cost,unfortunately.
also,i don't like scrapping anything that was built properly.

 

[Matrixx]

Sounds like your doing well, you caint swap AVR's between different machines. the new controller i mentioned is well under 100 (but I am in the trade) and a very good make, Comap, but if the rusty panel works why change it. it was just the state of the machine that makes me think it has been exsposed tho the elements, for non essentil use it will probelry be fine. good luck.

 

[bwservices]

you can get an avr to suit any generator
http://www.roperelectronics.co.uk/automatic-voltage-regulators/roper-electronics-avr-s.html
thebit of surface rust on the panel wont bother me