New Stator - Votage lower at higher RPM! - Kawasaki Vulcan 750 Forum : Kawasaki VN750 Forums
Electrical
Where does this wire go?
Includes Electrical mods, Lights, Stator,
Rectifier, Diagrams, etc

Reply
 
LinkBack Thread Tools Display Modes
post #1 of 35 (permalink) Old 10-01-2009, 11:23 PM Thread Starter
Skierbob
 
Join Date: May 2007
Location: Northern Vermont
Posts: 20
iTrader: (0)
 
Exclamation New Stator - Votage lower at higher RPM!

I just replaced my old shorted out stator and got wierd results when checking the bike with the new one. At just above idle (about 1500RPM), I get 14.2 volts but as I rev the bike higher the voltage drops til it is only about 13.6 v at 5,000 RPM! With the top two fuses out (i.e. no lights), I get .2 to .3v more but the same strange drop as RPM climbs. The R/R passed the Clymers resistor check before replacing the shorted stator. Any suggestions about where to look next for the problem? I'm worried that whatever is drawing enough current to cause the voltage to drop at higher RPM is what blew the stator in the first place.

Thanks in advance for any suggestions.
Skierbob is offline  
Sponsored Links
Advertisement
 
post #2 of 35 (permalink) Old 10-01-2009, 11:53 PM
Linkmeister Supreme
 
OlHossCanada's Avatar
 
Join Date: Aug 2008
Location: Lethbridge, Alberta, Canada
Posts: 7,960
iTrader: (8)
   
Welcome back Skierbob, I see the only other post you ever made here was 2 years ago last June. Where ya been? I can't help with any explanation for the wierd voltage readings dropping as the rpms climb higher. lance328 will be around sooner or later, and have some advice for where to start looking. Now ya'll come back, ya hear.

Gordon

1991 VN 750 -"Cosmic Lady" or "Bad Girl"?
Purchased May 16, 2008
Approx.19,300km (12,000 miles)

H-D windshield
Relocated R/R
MF-AGM battery
Fiamm Freeway Blaster horns
F&S luggage rack and engine guard
Kury Offset Hiway pegs
July 13, 2016, Riding on the DARKSIDE now, Classic Radial 165/80-15


TOP TEN THINGS A NEW RIDER/OWNER SHOULD DO. Click on link.
https://www.vn750.com/forum/11-vn750-general-discussion/9127-top-ten-items-you-would-suggest-new-owner-do-his-new-ride.html
OlHossCanada is offline  
post #3 of 35 (permalink) Old 10-02-2009, 12:04 AM
Now what
 
Ironman's Avatar
 
Join Date: Jun 2004
Location: Renton, Wa. USA
Posts: 400
iTrader: (0)
 
That's weird for sure. But as long as you get over 13.5 volts at over 2500 rpm, and less that 15 or so at 5000, the system's doing what it's suppose to.

'04 750A- and loving it!
VROC 13864
Using a Purlator One PL14610
"Sixth gear? I don't need no stinkin sixth gear!"
If someone throws you under the bus-remember to tuck and roll
Ironman is offline  
 
post #4 of 35 (permalink) Old 10-02-2009, 01:08 AM Thread Starter
Skierbob
 
Join Date: May 2007
Location: Northern Vermont
Posts: 20
iTrader: (0)
 
Thanks for the responses. I guess I'lll just nose around a little more and put some 20 Amp fuses in the stator outputs and ride it with my fingers crossed if I can't find anything else wrong. I sure don't want to replace the stator again. What a pain! Thank goodness for all those on this forum that have gone before me on this.

As for where I've been,... riding of course! About 6,000 miles a year, all pleasure. Ride on everyone!
Skierbob is offline  
post #5 of 35 (permalink) Old 10-02-2009, 01:18 AM
Simple Solutions
 
seebeeare's Avatar
 
Join Date: Jun 2008
Location: SEQUIM, WA
Posts: 965
iTrader: (3)
 
Send a message via MSN to seebeeare Send a message via Yahoo to seebeeare
Quote:
Originally Posted by Skierbob View Post
Thanks for the responses. I guess I'lll just nose around a little more and put some 20 Amp fuses in the stator outputs and ride it with my fingers crossed if I can't find anything else wrong. I sure don't want to replace the stator again. What a pain! Thank goodness for all those on this forum that have gone before me on this.

As for where I've been,... riding of course! About 6,000 miles a year, all pleasure. Ride on everyone!
you would be better off with a olt meter to monitor it... if u fuse the stator and one of the 3 legs go your bike is gonna try and send excess power though the other two leads causing the stator to operated at a higher temperature and the wire's wont be capable of allowing that much current through... fuses will do more harm then good...



Stator #3
MF AGM
DeGoated
Ears Shaved
R/R relocated
Rebuilt



She's worth her weight in GOLD
If u dont have it already Here is the Service Manual
How To Test the Stator
seebeeare is offline  
post #6 of 35 (permalink) Old 10-02-2009, 09:29 AM
Members who have donated towards server costs
 
fergy's Avatar
 
Join Date: Mar 2006
Location: Kyle, Texas
Posts: 4,054
iTrader: (3)
   
This sounds to me like your r/r is acting up. I know you said it tested good, but it is, after all, a voltage regulator and it sounds like it isn't regulating correctly!

Fergy
Kyle, TX VN750.com member #707 VROC#19556
2002 VN1500 Classic
Spline Lube Procedure, with photos, R/R Relocation and Coil Mod
Rusty Tank Cleaning!
Electrical Fault Finding Flowchart
SEAFOAM JUNKIE!


fergy is offline  
post #7 of 35 (permalink) Old 10-02-2009, 10:50 AM
Old Truck Junkie
 
niterider's Avatar
 
Join Date: Jul 2007
Location: Roby Texas
Posts: 4,130
iTrader: (15)
 
I replaced my r/r. Now I get 12.5 volts most of the time at any rpm. When I add a load to the system it goes up to 13.4 or so. The volts do drop down at idle rpms.
I replaced the r/r because erratic readings. At times it would go over 15 or 16 volts.

02 honda sabre 1100
niterider is offline  
post #8 of 35 (permalink) Old 10-02-2009, 11:52 AM
Member
 
Join Date: Mar 2009
Location: Fort Worth, Texas
Posts: 75
iTrader: (0)
 
I had a conversation with Tim at TPE about fusing the stator. He had never heard of it and felt that doing so could acutally hurt the stator. The stator puts out full voltage all the time, it is strictly mechanical, has no regulating capability, and the 3 legs work together. If you take out one leg, the other two are are less capable of putting out the required voltage but the demand is still there. Since they are less capable of putting out the required voltage or amps, the other two fuses will never blow. A volt meter is a much better way of monitoring the charging system. Kuryakyn makes a nice little unit for a reasonable price, I put one on my bike, mounted it right between the gauges and it looks nice. It's got a dimmer for night riding.

http://www.amazon.com/KURYAKYN-GAUGE...498556&sr=8-19
AceMcgyver is offline  
post #9 of 35 (permalink) Old 10-02-2009, 12:38 PM
Members who have donated towards server costs
 
Join Date: Nov 2008
Location: Finland
Posts: 369
iTrader: (0)
 
I do have a theory..

Look at the pictures below:
- Blue line is stator output voltage at low rpm.
- Red line is stator output voltage at a higher rpm.
- Black line is the battery nominal voltage.
- Green line is the charging voltage R/R is trying to achieve.

The first picture shows one positive half wave of the stator output voltage.
The second picture is a detail of the first one, where the voltage rises beween the battery voltage and the charge voltage.





While the voltage is below the battery voltage, there is no output from the R/R and a voltmeter will show the battery voltage. As soon as the voltage rises above the battery nominal voltage, the battery starts to receive charge current. But when the voltage goes above the R/R set voltage, it cuts off the R/R output. I have colored the triangles where charging occurs. As you can see, at low rpm the triangle area is larger than at higher rpm. Since a voltmeter shows the root-mean-square (effective) value of the voltage, it will actually show a higher reading at lower rpm. I used the same timescale for both cases (lazy me), but actually the dirrefence is even more when the blue curve is stretched. On the other hand, at higher rpm those red charge pulses occur more often, which compensates.

In practise the stator output voltage is not as clean as in the pictures. As soon as it gets above the battery voltage, it is the stator which supplies all the power + the charging current. This tends to restrict the rise of the output voltage. But with a battery which has seen it's best days, less than perfect connections to the battery and a light load, you could see a lower voltage at higher rpm.

Did it make any sense to you? Could explain what niterider is seeing.
pappa is offline  
post #10 of 35 (permalink) Old 10-02-2009, 09:38 PM Thread Starter
Skierbob
 
Join Date: May 2007
Location: Northern Vermont
Posts: 20
iTrader: (0)
 
Thanks Pappa for a great explanation of my readings and AceMcGyver and Seebeeare for the comments on putting fuses in the stator outputs. Pappa, your graphs make perfect sense and make me much more comfortable that all is probably well with the bike.

I am very concerned now with the fuses I put in my stator outputs. I thought I read that a few other people on this forum did this so I thought it was a tried and proven insurance policy. Anyone else want to weigh in on this before I pull the fuse holders back out of the circuit?

By the way, the bike is running great! Nothing like a hot spark to notch up an already hot ride! In fact I'm not sure the bike ever ran this good. Makes me think the stator may have been bad since I bought the bike for my wife with 2700 miles on it three years ago. I thought I got it for a great price but I guess not if it was already needing a $800 - $900 repair. Oh well, chalk it up to experience. All's well that ends well!
Skierbob is offline  
Sponsored Links
Advertisement
 
Reply

Bookmarks

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Kawasaki Vulcan 750 Forum : Kawasaki VN750 Forums forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

Once registered, your User Name"cannot be changed". We can make exceptions within 7 days, but after that, it is set in stone.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome