Hello John Talley here with Partzilla.com. Today we're going to be
taking a look at the stator that is used on most of your ATVs, side-by-sides, and
motorcycles. There's a couple of different types and there's very
specific ways we can look at them and test them so let's head over to the
table and start talking about how to test them to make sure they're working
properly. So let's go.
So what is a stator? Well actually is a fixed set of coils that's mounted inside
your engine. And how it develops power is there is a set of magnets that rotate
around the axis of it and by doing that it produces an AC signal. The examples I
have out, each one is what I call a three-phase type stator. Now they make
single-phase stators, but most of the time you're going to find that on a low
power demand machine but for most of your utility ATVs, UTVs, motorcycles?
Sometimes it can get a little power-hungry so they need the
three-phase system. So basically what you have are three different windings that
are wrapped around these different points and then they end up coming out
into a plug. Sometimes it may have the the pickup in there as well as this one
does from Honda. Then again, it may be a standalone like with the Polaris unit
where you only have the windings coming out. The pickup coil is actually separate.
Another example, Yamaha. They had the pickup coil and then
you have the windings coming out into this plug. All right these are just three
different examples of the same type principle that we're talking about. Now
how do you test this? Well there's two different tests that you can do. One is a
static test, and the other is dynamic test. Now dynamic test you actually take
measurements on the machine with the machine running sometimes that's not
always possible if your machine is not working at all and that's when you have
to do just a static test. Most of your static tests involve measuring going
from coil to coil or from coil to ground. So we're gonna pick one we're going to
show you how to do it, and I'm going to show you the variances as far as the
range that you can run into depending on which manufacturer you're dealing with.
Another huge dependent is which type of volt meter you probably have sitting in
your tool box. I've got three different ones laid out here. One, just one I picked
up at a local hardware store. The second, one one, from Fluke which is actually
geared toward the automotive industry. And then another one from Fluke which is
more advanced, much more sophisticated. So let's look at the Honda one first. If you
were doing a static test on it what you would do is set it to ohms. Then notice
something here. Right now it says OL. That means this
open circuit and if you put these two points together it should try to read as
close to zero as possible. Which it does. So to measure it going from phase to
phase, you just go from one to two. And it reads 0.5, 0.5 ohms. Now this one is
supposed to be somewhere in between 0.1 and one ohms and it's pretty much right
in the middle where it should be. Next you would go to phase two to three. Point
three, point four, point five. So once again right in the middle. Now you go
from one to three. Point six, point seven. So it's right there in the middle. When
I'm talking about phase to phase, I'm talking about the windings of each one
of these coils. And what you can't see and what is actually inside of here is a
Y so you've got that center point where all three of these coils are connected
in the middle. And then the end of each one of those coils is represented by the
wire coming out to this connector. So it looks like a Y and this is what they
call the Y configuration. Now, let's take a look at the Polaris unit. Here's where
it starts to get tricky: it's range is 0.07 to 0.13. A much tighter tolerance.
Now when you get to take a measurement on it, point 1. Now what is it? Is it 0.1
is that 0.09 is that point 11? It can't tell you because it is only accurate to
a tenth of an ohm. Let's go to the Yamaha now. It's even more stringent. Its range
is from point 1 to point 132 ohms. Now how in the world are you going to
measure that with just a standard one? Well you can't. So what would you do if
you've got a Yamaha unit and you're trying to diagnose a non-charging system?
Well, unless you're willing to go buy this particular meter, I don't really suggest
the static test is for you. But just for fun,
let's show you what this one can do. We've got it flipped over to ohms. And I want you to pay
attention to this. Let's see if it can actually hit absolute zero. That's
connected together, it should read zero. Look at that.
It's reading 0.09 ohms. You know what that actually is? That is the resistance
in these wires. But, this one has a feature called relative to where we can
in essence zero it out. Alright, now it reads zero. So, let's go to the Yamaha.
Point 13 ohms. It's in there. There's no possible way for you to measure that
with either this Fluke or just one that you're going to pick up at your local
hardware store. You would have to go up to this meter to do it. So in my opinion.
for most people out there, the best tests you can do if your machine is running is
to go to the dynamic test. That'll give you a much clearer picture as to what's
going on in your machine. There is one thing that you can check on all three of
these that's in common though. What we want to do is measure each phase one two
and three back to the ground or the body of the stator itself. And what we're
looking for is just an open or OL. Now we are just measuring resistance, so it
doesn't matter about the polarity. Alright, going from one to the body OL.
That's what we want. And we're gonna see that on all three of these wires or
phases. You're going to see the same thing with the Polaris as well as the
Yamaha. So let's recap. What can you really test would just your average
meter on a stator? Well, if you're looking for either an open from each phase going
back to the case. Or you want to see something close to
zero ohms going from phase to phase. If you've got those two readings? Well that
at least is getting you in the ballpark. If you do this measurement and there's
nothing there going from coil to coil? Well that means there's a break in the
line somewhere in your stator is damaged. So the best option if your machine is
running is to actually do a dynamic test. At that point you're not measuring
resistance anymore. You're actually measuring AC voltage. So you would flip
it over to AC, put your leads in the same place, start it up, and you will be
looking for range somewhere in between twenty and thirty volts AC and it's
going to rise and fall as you accelerate the engine and then let it slow down. Now
if you want to learn how to do that in depth, we actually did the procedure on
this machine. If you would reference that video and
I'll walk you all the way through doing a dynamic test on it.
Listen, if you need any parts for your machine why don't you come see us at
Partzilla.com and we can get you taken care of. Have any questions or comments?
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