11/18/2010 Page update, we no longer sell parts for ST heads, this is an informational page only, I leave it in place as part of our archives.




I encourage you to junk the stock dog house and all that is inside..


Above: Stock  ST_ rectifier, is JUNK, I encourage you to never buy a stock replacement! Always replace this unit with a western style unit. EJP has some in stock, see below.

Above: Part ST_ Brush holders, and mounting

Above: Part # ST_BRUSH SET, Best ST heads use 4 brushes,


How do I get this unit up and running fast  if something breaks?"

Let's look at the makeup of this genset, you'll see there's not much we can't do for ourselves.

Cast Iron center housing, cast iron bell ends, rotor, stator, slip rings, brush rigging, brushes, bearings, 11 bolts, a volt meter, a rocker switch, a full wave bridge (diodes).

There's really only a hand full of parts you'll need to call on us for.  It is my goal to find a 2nd source for most parts in these heads. At present, I am certain that everything can be replaced with stuff you can find locally. I've decided to stock brushes, switches, volt meters, diodes and that sort of thing here, we'll do our best to keep prices reasonable, but it's easy to find a substitute part locally.

The bearings have the common number right on them, you can go to a bearing house and give them that number, they'll probably have them on the shelf. There are a number of discount bearing houses on the internet. Emerson Bearing is a great one. Bearings usually give you some warning that they are developing a problem, this may give you time to order a new one before it gets really bad. If you want to be prepared for anything, you might stock a spare set?

There really isn't anything else in the head that should wear out. If a  winding were to fail, you should be able to locate the problem with an ohm meter, if you are reasonably handy, you might replace it yourself. If not, the local rewind shop should have no trouble working on this head. If a winding is damaged, the shop would remove it, match the wire gauge, form a new winding matching the number of turns and solder it into the rest of the circuit.

11/2003 an added note..

As of this date, I have experienced one failure of a stock diode rectifier bridge. I have also received two requests for this part from other ST head owners. At this point, I'd say the rectifier is the most likely part to fail in the head, there just isn't much else in the design other than the brushes. This does not mean to say that this is a flaky part, we suspect that these failures resulted when prodding and poking around, and possibly shorting out the field lead or worse.

What I've done below is fit  a standard North American rectifier bridge versus using a Chinese unit, you can buy them for $5 to $14 depending on the supplier. I do this because to demonstrate that you are not dependent on me or anyone else for parts. The field current and voltage is listed on the tag of ST Gen sets, this should be all you need to assure that the full wave bridge rectifier you select is adequate to handle the voltage and current, If I find a good place to order, I'll list same here, but this is a real standard part, and shouldn't be hard to find. Radio shack used to stock them.

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Above is a picture of an older style head with the early modification in place. The side terminals are a bad idea, I will leave this picture up as there are a number of these out there. PS and Utterpower have been working together for a number of years to build the better ST Gen head, as of 05/2006, we have made a good deal of progress, and we are still working to improve the product. Kiss engineering demands that you eliminate the dog house entirely, this dog house was originally designed to house a bulky old Selenium rectifier, the stock Chinese unit is air cooled as well, and a bunch outdated. Mounting the volt meter on the Generator head is the worst of ideas.    

The little square device bolted to the inside of the case with the four leads is the new North American style rectifier. You should get four female spade connectors to match the male connectors on the new part. If you don't have a proper crimper, borrow one! What you see here is an old mounting position, the rectifier is best placed in the end bell.

Note that this part uses the dog house as a heat sink, so make a good clean connection, and consider using some heat conductive paste between the part and the dog house, I have used a little anti seize for this connection, but I'm not positive it's anywhere close to the real thing. do note that this part is found it lots of consumer heads, I have replaced one in my Coleman generator, and there was no conductive past used there...maybe that's why it failed?

Above picture is left here as part of the archives, I  highly recommend mounting the western style rectifier in the bell end, brush side.  

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To the right of the screw driver is the Chinese style bridge rectifier, if you count the number of parts and screws, you'll quickly see there is plenty to rattle apart, and it has! Get the new western style rectifier!

A Gen set with a bad rectifier bridge will often have zero output. Pull the rectifier from the circuit, and use an ohm meter to read the Harmonic winding, if it looks good check the field winding and brushes, if they're good, suspect the rectifier.

 See our trouble shooting page.

George B.