Get information on Eagle, GMC, Prevost, MCI and other bus conversionsRV and bus conversion info since 1996.
Share Your Feedback    
       
 
  PRINT PAGE 
 
 
RV Classifieds
  1999 Damon UltraSport DIESEL - $49,500
  1999 Airstream cutter 35' diesel pusher - $85,000
  Demco Kar Kaddy KK360SB - $1,000
  1972 MCI MCI-7 - $50,000
  2006 Keystone Hornet 27B - $18,000
  VIEW ALL
  Search RV Classifieds  
  Classifieds Policies
  Benefits for Dealers  
  Sell Your RV  
  Dealer Signup  
 

Useful Links
 
RV Community
  Discussion Groups  
  RV Articles  
  RV FAQs  
  RV Classified Ads  
  Virtual RV Park  
  Shop at our Store  
  RV Lifestyle Books  
  Rate Your RV  
AllThingsRV.com
  MyRVGuide.com  
  RVMechanic.com  
Advertise With Us
BECOME A MEMBER
RV Resources
Best Rate RV Loans
e RV Loans
Visit Rio Rancho, NM for Winter
  RV Dealers  
  RV Manufacturers  
  RV Rentals  
  RV Glossary  
  RV Types  
  RV Ratings  
 

Lestek alternator output

Home > Discussion Forum > Mechanic's Corner - Electrical

Email Author email John Ogletree  Reply to Message reply to message  Post New Message post new message      search forums
hidden layer
ATTENTION: All Postings that advertise items for sale will be deleted from the Discussion Forum. You may post sale items for free in the Classifieds section. Sign up now.
All Messages in ThreadAuthorDate
Lestek alternator output John Ogletree 8-5-03  
My Lestek alternator is a dual output version, elininating the need for an isolator. The problem is that one of the outputs is putting out 16.5v. The other one is at 14.25. The measurement was made at the alternator terminals at a fast idle.

All helpful tips appreciated.
Re: Lestek alternator output Gary CC NV 8-6-03  
What do they both say after running for about 20 minutes, with everything off? About the Same possibly.
Re: Lestek alternator output Joe 8-6-03  
Which side tested high? Was it the vehicle side or the coach side?
Re: Lestek alternator output FRED 8-28-07  
HI FRED WITH THE WATERFORD FIRE DEPT. I HAVE A 1986 CHVEY 1 TON WITH A 460 IN IT. USE TO BE A MILITARY AMBULANCE WE GOT IT IN 1994 CHASSES ONLY WE PUT A FRIE BODY ON IT. IT HAS BEEN WORKING FINE UP TO LAST MONTH AT A SCENE AT NIGTH HAD ALL THE LIGTH GOING ABOUT 45 TO 1 HOUR IN THE LIGHT DIMED WAY DOWN SO SHUT OFF ALL RED LIGHT AND HEAD LIGHT LEFT ON THE TWO SPOT LIGHT AND THE LIGHT CAME ON BRIGHT LIKE THAY SHOULD THE TRUCK WAS ON HIGH IDEAL AND IT IS A TWO ALTERNATOR SYTEM HAD BOTH TESTED AN WORKED FINE. I PUT TWO NEW BATTER IN IN JUNE. WHAT COULD IT BE?
Re: Lestek alternator output John Ogletree 8-7-03  
Joe, sorry I wasn't explicit. The high voltage is going to the coach batteries (2 12v in parallel).

Gary, what do you mean "with everything off"?
Re: Lestek alternator output David Hericks 11-17-05  
I recently (Nov 2005) called the number for LESTEK in Ft. Worth Texas. That number is now answered by Penntex alternators. I was told that Lestek went out of business in August 2004, and Penntex now owns the old Lestek Mfgr facility. However, they are not building the same alternators a Lestek and they don't have any info for the old Lestek alternators/parts.

I have a Lestek Dual isolated output 160Amp alternator that I need documentation for. If anyone knows of a source for Lestek alternator specs and/or manuals I would appreciate knowing.
Re: Lestek alternator output Gary CC NV 8-7-03  
I would be willing to bet that the, "one of the outputs is putting out 16.5v." is the Coach side, because their is more power demand, for the TV and such. And the, "The other one is at 14.25." is for the starting the engine of the motor-home side. The usual Charging rate is 13.6 at 70 degrees. After the battery's have been brought back up to full charge,after about 20 minutes. If these charging Rates stay this high for more than a couple minutes, their is a definite over charging problem. Be very careful around the battery's,Especially if they smell like Rotten Eggs. Their Sulfated, and Very Explosive.Do Not Make, Any Sparks,like when taking off a battery cable, Remove the Negative battery cable from the other end of it's connection, Frame, Engine Block. On Flames any where near the battery's. If the Battery's are in bad shape, before touching them, rinse them with little water, and sprinkle them with Baking Soda, that will Neutralize the Battery Acid. And rinse them off again.
I hope this helps.
Any more question's,don't be shy, we're all here to try and help one another.
Re: Lestek alternator output Tom Clayton 9-16-03  
Does Lestek have a web site?
Re: Lestek alternator output Sam Watson 8-7-03  
According to the Lestek specifications, voltage should be 14 volts at both output terminals. One terminal is connected to a greater number of "turns" in the stator and therefore produces a higher amperage output( usually the rated output of the unit), the other output, being connected to a lesser number of "turns", produces a lower amperage output. Logic says the higher output should be going to the coach and it's batteries. Since I think there is only one voltage regulator involved, I'm trying to figure out how you're getting two different voltage outputs.
Re: Lestek alternator output Gary CC NV 8-7-03  
Hi John, what I'm trying to say is, check the voltage output after about 20 minutes, with the headlights off and A/C off, the TV off and coach lights off, give the batterys a chance to fully charge, without being needed for anything. Than I would think that the alternator would have the same output on both sides, because one side is not drawing more than the other, causing different charging rates.
Re: Lestek alternator output John Ogletree 8-8-03  
Excellent replies guys.

Sam, There is only one regulator. The alternator shop I took it to said it was putting out 130A at both posts. This was a bench test and I don't know at what speed but probably above idle. Does an alternator max out at a certain rpm? I do know that this one puts out a little more at a fast idle than at idle. Since this one puts out the same amperage at both posts I wonder if it has the correct stator in it. And yes, the higher voltage is going to the coach side, but 16.5v? BTW, a H.R. drawing of the 12v and 120v wiring refers to it as "Lestek 120 amp dual isolated output".

Gary, You're right, it is the coach side getting the higher voltage. Are you saying that the high output should drop within 2 minutes after the batteries are fully charged? Wouldn't the time it takes depend on the charge level when starting, or is 20 minutes just a normal time? BTW, all three batteries are new, with only a few hours use. Wally World Everstart. The biggest that would fit.

What would cause overcharging, bad regulator?

I'll try the test you mentioned.
Re: Lestek alternator output Sam Watson 8-8-03  
Yes, the Lestek uses a single external voltage reulator. The way an alt works is that a certain amperage current, determined by the voltage regulator is fed to one brush that rides on a insulated commutator or slip ring on the rotor. One end of a fine wire is attached to this slip ring and this wire is then wound around and around the rotor for a predetermined number of turns, then the end of that wire is connected to a second insulated slip ring which has a brush riding on it. According to the design, the voltage regulator may control the input current (amps), or the output current of the windings of the rotating field. The number of turns of the rotating field, which is nothing more than a rotating electromagnet, determines the strength of the rotating magnetic field, the more turns, the more powerful is the rotating magnetic field. As the lines of force( you've done the thing with a magnet, a sheet of paper, and iron filings haven't you?) of the rotating electromagnet field cut across the stator windings, an AC current is induced into the stator windings. This AC current undergoes full wave rectification by the diode array and is then available at the outlet tap(s). As you can see, the voltage output must be the same at both outlet taps on a dual, isolated alternator. Amperage can be different, depending on wheather or not the same number of stator loops are connected to the diodes and outlet tap. Since the Lestek has 12, 50 amp diodes as compared to say, a 65 amp alternator with only 6, 15 amp diodes, then I think a dual output, (just what it means), has two different stator taps, the current produced by each being rectified by its own 6 diode array. The amperage output of an alternator is speed related, voltage is not. For example, the Lestek 150 amp, dual outlet produces 115 amps at the high output tap, and 90 amps at the low one at an alternator speed of 3,000 RPM. From that point it climbs fairly slowly to a rated 155 amps at high tap and 123 at low tap at 6,000 alternator RPM. To see what that translates to in engine RPM, measure the alternator and crankshaft drive pulley and do the math to find the ratios---it is usually that the alternator rotor turns about 1 and a half revolutions for each crankshaft revolution.
Re: Lestek alternator output tim 8-9-07  
I need to find a replacement for my lestek dual output alternator. Where can I buy them?
Re: Lestek alternator output Burt McChesney 1-6-07  
I'm in La Paz Mexico installing a xantrex multi-stage alternator regulator to a Lestek 135 amp alternator.

The Lestek has four wiring connections:
A Ground lug. An Output lug. A dual bayonet plug and a small lug.

What's the small lug connected to?
Re: Lestek alternator output John Ogletree 8-8-03  
Sam, thanks for the in-depth description of alternator operation. Quoting from your last message, "The amperage output of an alternator is speed related, voltage is not."

Why then am I seeing the voltage at one output more than 2 volts higher than at the other? Can anything in the system produce a higher voltage than the alternator? I don't think the converter can do that, and I'm not even plugged into shore power. Is there any way the 7KW generator could cause it? Very perplexing.
Re: Lestek alternator output Sam Watson 8-8-03  
The only possible thing I can think of is that you may have some AC voltage piggy-backed on the DC output. That could happened through partial diode failure, ( leaking doide). That is easily checked by disconnecting the output leads and then check on continuity from the output terminals to the body of the alternator. Check with the the leads in one orientation, then swap the orientation and read again. There should be no read in either orientation if the diodes are good. Since both alternator outputs are connected to batteries, what are your voltmeter reads with everything connected and the engine off?
Re: Lestek alternator output John Ogletree 8-12-03  
Sam, I haven't done the diode check yet but with everything connected and engine off I read battery voltage on both terminals of the alternator. The starting battery is 12.6 volts or close to it. Just right. The two house batteries in parallel are about 13.5 volts, collectively and individually. Do you see that as a problem? I popped one of the caps and see that a fair amount of water has disappeared, presumably from boiling. How fast should house batteries lose water? I haven't really used this rig yet. Been working on problems instead. It's been plugged into shore power very little. I'd guess at about 8 hours of generator and engine operation.
Re: Lestek alternator output jack 8-21-03  
Where can I get a Lestec dual output
Alternator rebuilt?
It has locked up!

Thanks,
Jack
Re: Lestek alternator output J Ali 10-12-05  
Does Lestec have a website. I need to obtain an owners manual for the Lestec 105 amp, dual output alternator.
Re: Lestek alternator output Pat 6-11-04  
Alterstart systems inc in dallas, tx 1-800-607-0016
Re: Lestek dual output alternator Les Gaul 7-6-06  
Do you carry a Lestek dual output 120 amp (130 amp rating) for a 1986 motorhome with a 454 Chev engine. Could you tell me if there is a place in Canada that sells such an alternator. Since it is an older motorhome I am having problems locating such an alternator and your assistance would be greatly appreciated.

Les Gaul
Re: Lestek alternator output Bill Chaplin 10-26-06  
I have Motorhome (1986 Vogue) with Lestek alternator. I now have two alternators. I cary a spare since getting caught in Ohio 1996 with one out. Was a stranger in dayton and could find nobody to work on it. I found Doug Arnold @ Lestek, Fort Worth. He Shipped me one @ great expence. I also purchased a spare regulator which I have not had to use. Both of alternator have had a Lestek Overhaul. I run each about 250000 mile and pull it for new bearings and brushes. Try this number in Bedford Texas. I understand Doug has struck out on his own.
Re: Lestek alternator output Bill Chaplin 10-27-06  
Opps, sorry number is

866.285.7686
817.285.7686
Lestek alternator Alaska Ron 8-16-07  
I have a '86 Winnebago, Class A 454CID with Lestek Model 9135M, 105amp HD alternator, which completely locked up and smoked the serpentine belt. I pulled the Alternator out, but couldn't find a replacement any place. Finally found a repair shop who had all of the replacement parts as the Lestek alternator is the same body style and parts as the Delco 10DN style. Replaced the bearings and brushes; diodes tested okay. Reinstalled with a new serpentine belt, everything is working again.
Ron
Required fields in red
For more info about a field, place your mouse over the More Info icon.
Subject:
Your Name:
Your Email:
Message:



Code is case-sensitive. Helps stop SPAM.
       



Visit Rio Rancho, NM
PRIVACY POLICY  |  TERMS & CONDITIONS  |  © 1996 - 2008 RV-Coach Network - All Rights Reserved  |  Web Site by ITtelligent