I found the name of the replacement gen in our barth I gave the name in the title if you need parts you need the engine model they use all different engines I guess anything they can get their hands on. I ordered the parts yesterday they will be in today.they are in Leesburg. fl. phone no. is 1-352-365-2777
lenny

Lenny,
I have a PowerTech 7K with Kubota 3-cyl diesel. The documentation from PowerTech for 1995 was all 'preliminary' and the diagrams inaccurate. I drew up a schematic and explanation that I've given to a number of folks with similar setup. The other diesel used in '95 was a small CAT and should be similar. You can download both from:

http://www.altazip.com/~cebula/Powertech.pdf

http://www.altazip.com/~cebula/PowerTechOperation.txt

These may or may not be of use to you.

thanks I changed the oil pressure sensor and messed up the wires now it wont start .my problem is the person who had it before me changed the wires around now i don't know where I am at yet.
thanks lenny

Is the oil pressure sensor a one or two-wire sensor?

Mike

It is a one wire sensor .Before I get to that I thunk I have found out why it does not start.the house batteries of which I have 4 need a charge.
While I was working on the gauges I found another wire that was off of its connector put it on and did not look but my compartment lights were on.that was for 5 days.Low house batteries last time would not let me start the gen .It just clicked so I went under the coach and tried to start the gen. with the start switch and it just clicked.
what do you do with the wires that were on the sensor ? I am running a new wire from the gauge to the sensor. also is the wire on the back of the alternator ground or is it the positive ?
thanks for your help
lenny
PS I hate red wires and the tire ground is good

Interesting. I haven't seen a gen setup with an oil pressure gauge. Usually, the oil pressure sensor is wired to ground the pick to the run relay to kill it if the oil pressure is not up and thereby not allow the 'hold' voltage to exist on the run solenoid for fuel.

If you have a 'boost' switch to connect the chassis to the coach batteries, try that to start the gen.

Mike

Wait a minute. Did you say 'alternator'? What alternator?

AC generators are actually alternators

quote:

...also is the wire on the back of the alternator ground or is it the positive?...

True. But the above statement stopped me - there are a lot more wires going in/out on one functioning as a generator.

my genset on the Bluebird had a oil pressure, oil temp, and water temp gauges on the dash.

of course this thing had about 20 guages in it.

John

Yeah. Those had gauges that covered just about everything on the inboard and outboard engines, on the left side and the right.

on the kobota I have a alternator that is run with a fan belt it is small .built many alt housings .I am a diemaker by trade.if not a alt what is it?

quote:

Originally posted by Rusty:
AC generators are actually alternators

Yup

Nickel version:......When you come right down to it, all generators are alternators.

Dime version:........All rotary auto and truck type generators can produce only AC. Passing a coil through a magnetic field is a momentary (or transitory) event. You have to keep repeating it to get a continuous output. This repeating, or starting and stopping can only produce alternating current. If a DC output is desired, the AC current must be rectified.

Dollar version:......To convert the output of a generator to DC, the rectification can be done electro-mechanically by removing one loop of the armature at just the right time so that only the top of the sine wave form is used. This is done by use of a commutator and brushes.

It is difficult to describe this properly without pictures.

Electronic rectifiers have been around for over a hundred years, but didn't enter automotive use until solid-state technology and miniaturization combined in the mid-sixties. It was strictly a marketing term to call an AC generator with electronic (instead of electro-mechanical) rectification an Alternator. WOW! New Word. There was even an advertising stunt which involved driving a car across the country without a battery, once it was started. This could have been done with the old brush-type generator, as well, but it wouldn't have proven much. I just had to try it, and it worked if the generator had enough output at idle.

The newly-named Alternator was a better product, and could have stood on its own merits, but you know how marketers like a gimmick. In addition, the newly-designated Alternator included solid-state regulation that was an improvement over the 1920's magnetic regulator technology. A further advantage was that the carbon brushes didn't carry as much load, and there wasn't a commutator to eat up the brushes or itself. An alternator does have brushes and slip rings to carry exciter current, but they are pretty long-lived.

It wasn't too long before the regulator was mounted inside the alternator, which could run into heat problems, but was a cleaner installation.

Having said all that, in common usage, a generator is a rotary thing that makes electricity.

In automotive use, a generator is the early iron thing that makes DC electricity with a commutator, while an alternator is an aluminum (usually) thing that does the same thing with solid-state electronics.

In RV use, a generator is a thing that is turned by a motor to make AC electricity. Technically, the whole assembly is properly called a genset, but often a portable genset is called a generator.

It gets worse....... a portable genset which produces AC, then rectifies it to DC, and then inverts it back to AC is still called a generator.

None of this makes sense. Like Topsy, it just growed. Or, perhaps, evolved would be a better word, although linguistically, there has not been any improvement. But the technology has certainly improved.

Trivia:.....On airliners, the thing attached to the engine that goes round and round to make electricity is called a generator. They are driven at a constant speed hydraulically to keep frequency stable, regardless of throttle setting. Inside them, they have what we would call an alternator to excite the field to get it started with DC. But, perversely, they call it a generator, specifically a PMG, or permanent magnet generator.

To make matters worse, at the airport, a big genset mounted on the back of a truck is called a KVA, standing for Kilo Volt Amps. This probably came from how they were rated.

On light aircraft, automotive terminology is used, to match the automotive parts used.

So, it is hard to really know what is what.

quote:

Originally posted by lenny and judy:
on the kobota I have a alternator that is run with a fan belt it is small .built many alt housings .I am a diemaker by trade.if not a alt what is it?

What it is is unusual. PowerTech's 7KW generator has the normal dual 120 VAC capability and also has a 12V charge function. No need for any sort of alternator. Usually, the 7KW is set up with its own 12V battery for starting and is in turn, charged by that 12V charge function. That generator battery is also usually charged along with the house batteries by whatever methods they get their charge, but is diode-protected from draining back to them. Of course, whether or not to use a separate starting battery for the gen is up to the coach maker.

Not sure what year vintage gen you have, but it seems different from the normal setup from PowerTech.

quote:

Originally posted by Relative:

What it is is unusual. PowerTech's 7KW generator has the normal dual 120 VAC capability and also has a 12V charge function. No need for any sort of alternator. Usually, the 7KW is set up with its own 12V battery for starting and is in turn, charged by that 12V charge function.

FWIW, my Kohler 7C21 has 12 volt charging capability.