AC 620 Onan-Voltage to stator?
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Category: Allis Chalmers
Forum Name: Garden Tractors
Forum Description: A great place to discuss the Simplicity and Allis Chalmers Garden Models
URL: https://www.allischalmers.com/forum/forum_posts.asp?TID=80154
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Topic: AC 620 Onan-Voltage to stator?
Posted By: macvette
Subject: AC 620 Onan-Voltage to stator?
Date Posted: 12 Nov 2013 at 5:51pm
 Still grief with my Onan CCKB failure to charge. Now has a used flywheel and stator that came from Sandy Lake, new Onan regulator, new Onan rectifier. Still no charging. Connections have been checked. Mechanic has used Al Edens checklist from Onan. Something has fallen thru the cracks on this situation.Wonders what the voltage to the stator should be to start cycle of charging? Anyone know? Thanks.
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Replies:
Posted By: Dr.Fiero
Date Posted: 13 Nov 2013 at 10:17am
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I haven't worked on that particular model, but... most would use 12V to flash the field, then it could ramp all the way up to as high as 90+V in operation. I would highly recommend checking out smokstak.com 's forum ------------- Current slow rides: '65 Big Ten, '79 JD 317 |
Posted By: macvette
Date Posted: 13 Nov 2013 at 12:39pm
| Thanks. Will check out smokstak. |
Posted By: ACook
Date Posted: 13 Nov 2013 at 1:13pm
| I went through this about a month ago. All of the components looked good when I ohmed them out with my DMM. When I checked the AC voltage coming from the stator it was a little low on one side at idle and hit 117 vac at full throttle. I decided to replace the stator and rectifier but keep the old regulator. After changing the components and making sure the regulator and rectifier were well grounded it still was not charging. I added a jumper wire from the battery straight to the charging system and found I had 13.6 volts DC. Make sure to check the rest of the wiring. The ignition switch has 1 terminal that goes to the charging system and was too rusty to pass any current. Sorry for the long reply. |
Posted By: macvette
Date Posted: 13 Nov 2013 at 3:02pm
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Welcome to the forum! Have gotten a lot of help from here, like you just gave me.Thanks for the reply. Connections have all been checked, wiring supposedly doesn't have any opens. Where did you join the jumper wire to the charging system? This will be my next job. |
Posted By: ACook
Date Posted: 13 Nov 2013 at 4:10pm
| Thanks for the warm welcome. I used a 12 ga. wire with alligator clips on each end. I went straight from the pos battery terminal to the white wire that hooks the regulator and rectifier to the charging system. This wire is the output from the rectifier and the regulator uses it to decide how much to charge the battery. |
Posted By: macvette
Date Posted: 13 Nov 2013 at 5:21pm
| Yep, just came in from doing that. Put an actual connector on tne white and connected to battery. No joy. Looked back at things I had tried previously, put a 12 volt headlight from white wire. Light was bright as reg headlight . Bummer. Still missing something. |
Posted By: Ages Cat
Date Posted: 16 Nov 2013 at 6:06pm
| This may be huge overkill, but we have a Case 646 with a CCKA that is not charging. Stator is open. Everyone that I have talked to says the Onan charging system was a weakness. With no more stators available from Onan, the solution is mount a compact alternator to the frame and drive it with a pulley from the flywheel. |
Posted By: macvette
Date Posted: 16 Nov 2013 at 9:54pm
| Curtis: Thanks for the info. Am on simpletractors.com as well, and a member over there suggested the same thing. I think that is the direction I may be heading next spring. Have asked that member to send pix of his install and briefly describe for me. If he does send that I will ask him if it is O.K. to share on our AC website. Waiting for some info from smokstak.com as well. |
Posted By: Ages Cat
Date Posted: 16 Nov 2013 at 11:15pm
| I have the alternator and am ready to work on bracketing it to the engine. When I get to the point that I have it installed, before I install the baffles, I will photograph it and post it. I have a single wire alternator and this mod will eliminate about 30% of the wiring. It will be simply a single wire to the ammeter. More to come. |
Posted By: rrhead(SD)
Date Posted: 17 Nov 2013 at 8:21am
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I would be interested in that as well. Thanks, rrhead(SD)
------------- 2 WDs,WD45,D-14,D-17,D-19D,180,7020,6080FWA,6080 2wd, 6080 2wd(cab),8050FWA,8550,4W-305,Massey 8250. Gleaner L3, R62 &R65 Agco-Allis 1616H & 1920H, AC 720, Terra-Tiger |
Posted By: Steve in NJ
Date Posted: 20 Nov 2013 at 4:48pm
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Before you wire a 1 wire directly to the Ammeter on that machine, I would re-think that idea! If you don't use that machine all the time, everytime you get on it to use it, the Battery will be low or dead. If you want to be smart (and safe) about it, wire a compact 3 wire Alternator through the key switch. This way when the switch is off, everything is off, and there will be no parasitic draw on board the Tractor from the Alternator or anything else. Let the Ignition switch be the master switch. Another thing, if that machine develops a short somewhere while you're on it, and you have wired direct, you'll set that machine a blaze, or burn everything else up. THAT is an expensive venture to replace or repair that mess. Leave 1 wire Alternators to Automobiles... Steve@B&B ------------- 39'RC, 43'WC, 48'B, 49'G, 50'WF, 65 Big 10, 67'B-110, 75'716H, 2-620's, & a Motorhead wife |
Posted By: macvette
Date Posted: 20 Nov 2013 at 7:04pm
| Steve = what is the approx cost of one of the compact 3 wire alt.? |
Posted By: Steve in NJ
Date Posted: 20 Nov 2013 at 9:12pm
There are quite a few different mfr's and types of compact Alts out there in the Automotive and industrial world. Denso, Mitsubishi, Bosch, and Motorola to name a few. Each have there own type of mounting, so careful research needs to be done when retrofitting one of these pint size units to one of these Tractors. Most of the small compact size Alts vary in the amp department also. They range from 33- 45 amps, and go as high as 72 amps on some diesel applications. The small amp units would work quite well on a 620 or 720 when upgrading from an antiquated stator system that is getting tougher and tougher (not excluding expensive) to find parts for. I just purchased a 620. It needs its engine repaired first before I can run it and see if the stator charging system is working. If it doesn't, you can bet I'll design a retrofit kit that will upgrade the old stator system for the 620 and 720 machines if possible and be a safe, reliable, and effective kit. I already have plans to upgrade the Ignition switch in mine. Sheesh! Cheap junky Indak switches they used! Yuk!  Forgot to add, some of these units are expensive. Some around $95.-$150 bucks. But you could have more than that in a stator system pretty quickly, and still not have the reliability...Steve@B&B ------------- 39'RC, 43'WC, 48'B, 49'G, 50'WF, 65 Big 10, 67'B-110, 75'716H, 2-620's, & a Motorhead wife |
Posted By: BrianC
Date Posted: 22 Nov 2013 at 10:39pm
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I was told the magnets in the flywheel can work loose, hit the stator and ruin it. And people are replacing the whole system with an alternator. I agree with Steve the ignition switch is cheesy. |
Posted By: Steve in NJ
Date Posted: 22 Nov 2013 at 11:03pm
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You heard right Brian. Had a few twin Kohler engine flywheel magnets come apart and take the stator right out along with some of the wiring. What a mess. Not cheap, not cheap! ------------- 39'RC, 43'WC, 48'B, 49'G, 50'WF, 65 Big 10, 67'B-110, 75'716H, 2-620's, & a Motorhead wife |
Posted By: Ages Cat
Date Posted: 22 Nov 2013 at 11:11pm
| The alternator is $150.00. I plan to remove the rotor magnets. |
Posted By: macvette
Date Posted: 23 Nov 2013 at 4:57pm
| One magnet came loose in mine, and ripped off the stator wires, tore everything up. This spring/early summer. Pulled engine, bought a used stator and flywheel - expensive -didn't help. Hired starter/alt. mechanic to use the Al Eden checklist to troubleshoot - varied results. Bought new regulator, didn't help. Bought new rectifier - didn't help. Had already checked ign. with a loose 12 volt headlight bulb to reg/rectifier assy to make sure was getting 12 v. all the way thru when switch was on. Bulb was bright. Total outcome= VERY EXPENSIVE, and still not charging. Spent money I really didn't have available to spend on this problem. Will be going the mini alternator route come spring, and selling the new Onan rectifier and new Onan regulator I purchased. (freezing my fingers in this cold will not happen for fixing this issue) Expensive lesson. |
Posted By: BrianC
Date Posted: 23 Nov 2013 at 8:56pm
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Would be nice if we had some good pictures of the stator and flywheel magnets. So the machines have some trouble spots... I hope mine stays together. |
Posted By: BrianC
Date Posted: 23 Nov 2013 at 9:45pm
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There are some pictures on ebay of flywheels. Some don't look too pretty. Seems like the flywheel on the Gravely version has some sort of alum retaining ring to perhaps prevent magnets from falling out. Anyone know what the stator pole to magnet gap is on the 620? So looking at a block wiring diagram of the charging system I say huh? |
Posted By: Jerry/IN
Date Posted: 24 Nov 2013 at 11:03am
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Steve What ignition switch do you recommend to replace the Indac switch?
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Posted By: Steve in NJ
Date Posted: 24 Nov 2013 at 4:08pm
To be honest with you Jerry, I didn't look at the OEM switch yet to see what would be a good replacement that will fit in the original's spot. One of my good customer's that's very familiar with these machines mentioned today, the Indak switch is special to the 620 and 720's to energize the electric clutches. Looking at the wiring diagram that was posted in another thread, doesn't look anything special to me. I have a service manual coming to get familiar with the machine and its circuitry. But as I mentioned, looking at the wiring diagram, doesn't look anything special to me. I'm sure I can come up with a nice heavier Ignition switch to do the deed, but at the present time with 620 outside under a tarp, and it being 27 degree's out, I'll stay here in the shop and keep working! I'm a real "wee-wee" when it comes to the cold. The older I get, the worst I get!  Steve@B&B ------------- 39'RC, 43'WC, 48'B, 49'G, 50'WF, 65 Big 10, 67'B-110, 75'716H, 2-620's, & a Motorhead wife |
Posted By: Jerry/IN
Date Posted: 24 Nov 2013 at 7:23pm
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Steve thanks for the reply on the Indak ignition switch. I like the cold less and less every year myself.
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Posted By: Tracy Martin TN
Date Posted: 24 Nov 2013 at 9:01pm
| I would also be interested in the ignition switch fix and alternator fix. Both are trouble points on these tractors. Thanks Tracy |
Posted By: Steve in NJ
Date Posted: 26 Nov 2013 at 9:22am
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I got brave yesterday afternoon. The temp went up to 34, so I took a break from the shop and zoomed out and removed the Ignition switch from my 620. The curiosity was killin' me. After a quick fuel tank removal, I was able to assess what's goin' on behind the dash. Just as I suspected, a cheesy, junky Indak switch with a lot of green puss growing all over it. With close to 40 different Ignition switches in stock, it didn't take me to long to come up with a candidate, to do the job, with a matching plug. The thing I did notice when pulling the OEM switch out is the big dash support that runs right behind the switch! Might be a problem for the new switch. To get the new switch to fit nice, grinding a little half moon in that support might be in order. OR lowering the hole in the dash a little. The new switch has a 7/8" mounting barrel, so a little inginuity needs to be applied here. I'll have to do my homework on this one yet.... stay tuned... Steve@B&B ------------- 39'RC, 43'WC, 48'B, 49'G, 50'WF, 65 Big 10, 67'B-110, 75'716H, 2-620's, & a Motorhead wife |