Just got my ST head for the new project...

[rocketboy]

$600 delivered to my house with a pulley and SK bushing. Super quality and good support from Eric Lyons at Rocky Mountain Power Source. Today it gets the copper paint treament to match the rest of the GEN SET!



 Brush block... nice quality here as well...

[Doug]

Delivered to your home for 600.00 USD.

You know whats realy shocking is that exact unit probably cost 75.00 USD in a crate at Fouzon...\

I found that Locktight gasket chisel removes any paint or coatings.

And I think you would be well served to wash the entire windings with a quality contact cleaner and give it real good bath in air dry insulating vanish. Some pictures I have seen lead me to think the Chinese are very cheap in the dip and bake dept....

Doug

[emerald]

The cheap ones wouldnt even be that cheap (75USD) ex factory. The one pictured here is a good quality unit, it has two brushes per slip ring, and I will guess at its bearings being sealed too. If you get an ST head with that lot, your doing well. Other than checking the slip rings for any high spots, there is nothing else you need do. The Chinese are very capable at making generator heads and it is unfair to put them down without knowing and seeing the heads in person. I have yet to see one with bad windings.

A check on the shaft diameter also tells the story, good heads of 15 and 20kW have 48mm diamter shafts. They should also quote you a continious rating on the head, and not peak like most western resellers do with their junk 3600 RPM gen heads.

I have been to factories which make these heads, if they put a sticker on it of a western manufacturer nobody could tell the difference. I have used them in the past and will use them again. Buying generator heads is no different to buying a Lister clone, you have to be prepared to put in the effort and buy some product. A good quality 5kW head weighs over 200lb. That is the first question I always ask.

The only weak point of the design, even on the 'good' heads, are the cheap dog houses. I remove them and build mine into a seperate control panel that has the engine starting button, kill switch and meter etc. Looks nice and neat then, plus you can add on the goodies such as trip etc.


Emerald

[Doug]

This brings up a question that been asked here before.
Who makes good heads worth buying and who makes bad ones we should avoid.

Since you've actualy seen some factories where these were made can you toss a few good names up?
And do you have any other tips we could  use?

Doug

[emerald]

Doug, the manufacturers build generators for anyone who has the money to buy. They are geared towards bulk manufacture and the end of line assmebly attaches the name of the client. It is likely that one factory builds heads for different markets, but with a different final specification. An example is the ST heads you see in the US are not for sale in the EU. Their heads will carry a CE mark. Internally, the heads are probably the same.

I could post dozens of links, but its tells you nothing really. Every factory build to a stanard the cusotmer wants, so a factory running one line with good heads, will also have another line bulding junk heads. To them it makes no odds what the qualoty is like, they get paid to build what is asked of them.

It is up to you the buyer to have a full speciifcation ready, and then they will quote you. But, single unit sales are not their thing, they do bulk and only deal with companies. I know this is not what you wanted to hear, I am just giving the heads up on how they operate out there. A sample order would work as once off, say a dozen pcs, if you can get a business to place the order.

The previous posts gave what to look for, here is the short version.

Weight - heavy means life span
Bearing spec and brand - should be sealed and major brand
Brush count - Less than two, walk away
Output shaft dimension - 15 and 20kW use 48mm, I have diameter of smaller heads too
Continious rating - Dont buy peak rated head.
Fan - metal better over plastic
Poles - Most have four, but do ask as its easy to get caught
AVR - Most will give +-5% voltage, any higher, leave it

When bearings go, as they all do eventually. A local replacement is easy to get, they are stock metric dimensions. Brushes are also common size. I have yet to replace any. Never had any coil failures either. They are a pretty good unit. You could go brushless too, but you have to ask is the expense worth it.

Hope that helps you some.

Emerald

[Doug]

Thanks, I don't realy have a lot of illusions about ordering direct but I know enough about electrical equipment to tell good from cheap.You know it realy is a let down to know what you want and have no easy way to get it.
Since you've seen them being built can you tell me are they winding these things by hand as was done in the old days here?
Does it look like much care and attention is going into dippping and baking?

Discribe what you've seen that would answere a lot of questions.

Doug

[emerald]

Doug,


The windings are wound by an automated process, then placed on a rotating rack that dips them into a vat for x time. I do not have the time they are in the vat, nor how log they are left to dry. Be an easy matter to dip them yourself if it is a concern. The Rotor insualtion rating is class B, and the Stator insualtion is class E typically. If left unused for long periods of time it is common for them not to generate when fired up again. But I guess you know the battery trick to bring them back to life.

It is not big problem as most people have the good sense to run a genset once a week or once a fortnight under a small load to keep it in order.

I have never seen any failures that could have not been attributed to the generator, all were 'user error'. Abused, over loaded and the odd one soaking wet or dipped in cement. Contractors are a tad rough on most things.

Emerald

[Doug]

Yes I know all about abuse and failure.....
I began my career in the electrical buisness as a motor rewinder.

Doug