Rectifier, anybody take one apart? - Triumph Forum: Triumph Rat Motorcycle Forums
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post #1 of 18 (permalink) Old 05-17-2019, 03:34 AM Thread Starter
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Rectifier, anybody take one apart?

Hi All, Quick question. Has anybody ever taken a rectifier apart to see what holds it together & see what's between the discs in the center bolt?

Bike in question is '73 T140, but I think they're the similar for many years.

On this bike changing batter I noticed the 2nd disc from the front (end that's not the mounting end) can slightly rotate on the shaft light the end nut may be not pinching stack tight.

The diode wires to next disc are intact. The charging system is working ok at the moment. All original alternator, rectifier & Zener etc.

Photos if possible would be very helpful.

Thanks, Don
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post #2 of 18 (permalink) Old 05-17-2019, 06:29 AM
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Don

Never took one apart and yes I have also seen them with a loose plate. The rectifer you are looking at (1973 T140) would be a part number 49072. This item was used from about 1966-1978 on Triumphs. It changed when the bikes went to Negative ground in 1979

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post #3 of 18 (permalink) Old 05-17-2019, 09:35 AM
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Originally Posted by TR7RVMan View Post
Hi All, Quick question. Has anybody ever taken a rectifier apart to see what holds it together & see what's between the discs in the center bolt?

Bike in question is '73 T140, but I think they're the similar for many years.

On this bike changing batter I noticed the 2nd disc from the front (end that's not the mounting end) can slightly rotate on the shaft light the end nut may be not pinching stack tight.

The diode wires to next disc are intact. The charging system is working ok at the moment. All original alternator, rectifier & Zener etc.

Photos if possible would be very helpful.

Thanks, Don
Hi, the plates do come loose, frequently, they are insulated electrically, and it's not a problem, until the connection wires between the plates fail, at which point it can damage the zenor diode and incrementally reduce the output. There are much more advanced power rectification units available with built in heat sinks as a single integrated unit no bigger than a packet of ciggies.

The cost is usually lower than the original setup, unless you are a 'original' officiardo. Any of the later machines (any Make) with a 12v & similar or higher alternator output in current delivery will suffice, Most have three phase cable facility, if yours alternator is two wire output, you will have a redundant connection, though you may have to source a wiring diagram to ID the colors. But the cost is quite low for a new unit, and well worth the money for reliability. Normally 4 or 5 cables total, 3 for alternator input, any way round, one earth connection, and the cable for rectified/controlled voltage output wire. If it has only 4 wires, then the units fastening holes are the earth.
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post #4 of 18 (permalink) Old 05-19-2019, 03:25 PM Thread Starter
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Hi All, I was hoping someone could take it apart to show exactly what the insulator bushings etc. is like. What are they made of? How hard are they?

There is a sleeve nut at front disc that seems?? to hold stack together. Then I have what appears to be a spacer sleeve?? with thick black paint. Then thick flat washer, tool tray, finally lock washer & non locking nut.

So it looks like I'd need to back off mounting nut, counter hold the through bolt head & first plate next to sleeve nut, then tighten sleeve nut.

I have no idea of how tight the discs should be. Interesting only 1 disc can be moved with fingers. It certainly still has some tension on it, but too easy in my mind.

Another question.... Are the discs & insulators bonded to the through bolt in any way with some sort of sealant? Or is there a plastic insulating sleeve around bolt. Obviously some discs must be insulated from ground. Or are the bushings stepped? That's the kind of stuff I'd like to know.

My rectifier has a tab connector under through bolt head with a red wire hooked to it. This wire is not shown on wire diagram. So it looks like the tool tray becomes a redundant ground?? Shop manual calls this connector capacitor ignition terminal. If my bike has a capacitor, I've never been able to find it. Ohm meter shows red wire is hooked to ground.

I was hoping someone had a bad one they could take apart. Pretty much no British swap meets in my area anymore.
Don
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post #5 of 18 (permalink) Old 05-20-2019, 09:42 AM
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Originally Posted by TR7RVMan View Post
Hi All, I was hoping someone could take it apart to show exactly what the insulator bushings etc. is like. What are they made of? How hard are they?

There is a sleeve nut at front disc that seems?? to hold stack together. Then I have what appears to be a spacer sleeve?? with thick black paint. Then thick flat washer, tool tray, finally lock washer & non locking nut.

So it looks like I'd need to back off mounting nut, counter hold the through bolt head & first plate next to sleeve nut, then tighten sleeve nut.

I have no idea of how tight the discs should be. Interesting only 1 disc can be moved with fingers. It certainly still has some tension on it, but too easy in my mind.

Another question.... Are the discs & insulators bonded to the through bolt in any way with some sort of sealant? Or is there a plastic insulating sleeve around bolt. Obviously some discs must be insulated from ground. Or are the bushings stepped? That's the kind of stuff I'd like to know.

My rectifier has a tab connector under through bolt head with a red wire hooked to it. This wire is not shown on wire diagram. So it looks like the tool tray becomes a redundant ground?? Shop manual calls this connector capacitor ignition terminal. If my bike has a capacitor, I've never been able to find it. Ohm meter shows red wire is hooked to ground.

I was hoping someone had a bad one they could take apart. Pretty much no British swap meets in my area anymore.
Don
Hi TRV, not got one to sacrifice, and not sure what you mean by 'tool tray', (Heat sink?) but in the days of Lucas, you can bet the spacers on the DC side of the diodes (placed between individual diodes plates) would be Bakelite, finished with a good coat of shellac (Beetle ****) I assume the center bolt is connected to two of the four DC output side of the diodes by virtue of a good fit in the plates, and secured by the nut, as this bolts to earth, The other two diodes insulated with sleeves/spacers and then running to the center output terminal with a 'spare' connector, which can be used to charge a capacitor (DC via the diodes) for battryless running on coil ign models, which would only be required for competition etc. If I remember correctly, the plates are aluminium, with a steel bolt, and this alone would account for some electrolytic erosion between the two, and no amount of tightening will overcome the corrosion. Lucas also had a habit of using materials that have a determinable finite life, maybe cos thats all that was available. No guarantee the diodes are good, but you can check these easily. If you want to 'refurbish it' I would suggest removing the bolt without disturbing / or renewing the soldered diode connections, clean any corrosion dirt off and reassemble using a good fitting bolt and modern plastic/silicon spacers. if you renew the finish, remember the heat sinks are just that and finish in matt black which has a better heat emissivity than gloss. Incidentally you can get anti corrosion paste/lubricant as used on computer heat sinks to prevent later damage between the plates and bolt. A good earth connection is all important from the bolt.Just trying to put a Lucas diagram on. No can't do. some reason more than the 20K allowed date limit. sorry. Still trying to get my head round this, but I'm sure you will correct me if i'm wrong.

Last edited by Freakmaster; 05-20-2019 at 10:49 AM. Reason: more info
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post #6 of 18 (permalink) Old 05-21-2019, 04:00 AM Thread Starter
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Hi All, Thanks for the info. I ordered a "good used" one that matches mine on Ebay. $15 free shipping. So I'll take it apart & see what I learn. I expect it's probably no good, but I'll test it first per workshop manual to see. Who knows, I might be able to clean it up & end up with a good spare?? I'd really like to know how the diodes are attached to the discs. Almost looks like the wire is soldered??, but the discs are aluminum. Should arrive in a week or so.
Don
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post #7 of 18 (permalink) Old 05-24-2019, 02:47 AM Thread Starter
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Hi All, The plot thickens.... Bike is charging to a degree, but not properly.

Remember the bike never did this until a few weeks ago. The battery would always be very close to 12.63 key off after sitting overnight. Would hold this for even 4 weeks or longer. Extended city riding would slow blinkers, but they would recover very quickly once sustained speed could be used.

Old battery was 5.5 year old Motobatt. Compared to new battery it did not have the capacity remaining it should have even after charging. Wasn't totally bad though. So I decided to get new battery as a matter of I can't truly test the old one & didn't want to take any chances on it. I was willing to blow $75 on battery just to have fresh one.

The new Motobatt came out of box at 12.91v. Bought direct from Motobatt so I feel it was fresh battery.

I went for short road test about 5 miles. Didn't have time to test charging volts with new battery.

Next day battery was 12.68v.

Testing charging volts in garage after cold start, no road test, but warmed motor at fast idle:
head lamp off: idle 12.37v, 4000rpm 14.25v.
Head lamp on idle 12.14v, 4000rpm 12.63. (original type 415 headlamp).

Went for 50 mile ride with a lot of stop/go city riding. Got home & checked volts key off. 12.42v. Not good... No time to test charging system.
Next day battery recovered slightly to 12.47v.
Stayed at 12.47v for 6 days. Until today.

Today I checked volts before start up key off. 12.47v.
I went for 92 mile ride today through canyons with rpm mostly 3500-4500 rpm. Minimal city riding. Headlight on all the time as I always ride with headlight on. I noticed about 1 hr out the blinkers were slowing down slightly.

Got home battery volts key off 12.09v. Yikes!

Tested charging immediately with bike still heat soaked:
Head light off idle 11.91v, 4000rpm 12.34v.
Head light on idle 11.69v, 4000rpm 12.01v.

After bike sat for 5 hours battery recovered to 12.14v

I'd have to test cold again to see if it's worse heat soaked or the fault is getting worse.

The rectifier I took a very close look at. One of the wires on the looser plate looks like the "solder" is peeling up, but wiggling connection with screw driver being careful not to contact other plates or frame the connection appears to still be intact.

On a side note it tested for quiescent draw with test light. Did not light bulb. I then tested with my digital inline ammeter. Shows zero. I then tested with my little 20ma meter, still zero. This was expected as battery volts didn't drop in 6 days.

Just for fun I did a little test of battery connection.... Just curious.
Placing digital volt meter between battery - terminal & power wire I get .9 volts lower than battery volts. I don't know if that's expected or not. Never did that test before.
Doing same test with old analog volt meter shows 6v.
I tested battery volts with both meters & they are within 1v so meters are reasonably close. Again I have no idea what to expect with this test, as I don't think it's even a real test. On cars this is normal but the clock & many computers have constant power demands.

My next step the way I see it is doing proper tests per shop manual step by step of alternator, rectifier, Zener. Volt drop wires with a load. I was thinking of using a car headlight for the load. About 55w.

MY next task is get a proper 1ohm resister. I have some resistor wire so might(???) be able to make one, but I'll have to see if it works as shop manual states. Never made one before.

Question to you guys versed in electronics/electrical testing. Shop manual states use good quality moving coil amp & volt meters. Is that really necessary? Or can I use my good quality modern digital amp & volt meters? I don't have moving coil amp meter.

For all I know I could have a bad wire or connector somewhere. Visual inspection shows ok though.

Thanks, Don

Last edited by TR7RVMan; 05-24-2019 at 02:54 AM. Reason: added sentence
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post #8 of 18 (permalink) Old 05-24-2019, 02:58 AM Thread Starter
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Hi Stuart, Question I feel you may have an answer to.

Suppose I need a stator.... Seems be perfect time to upgrade to 3 phase. But, will the 3 phase still allow my bike to start with flat battery? I am using points & don't plan on going to electronic ignition.

In this case what would you do for rectifier, regulator? Use the 3 phase rectifier & 3 zeners or what brand rectifier/regulator.

What is most durable & trouble free in you experience? Price is not a factor. I want the most reliable.

Or am I better off just replacing with what I have now?

Thanks, Don
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post #9 of 18 (permalink) Old 05-24-2019, 05:34 AM
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Hi Don,

Thanks for the confidence.

Quote:
Originally Posted by TR7RVMan View Post
Suppose I need a stator...
Nothing in your previous post says the problem is only the stator ... could be the rotor ... could be both. You know whether the existing stator and rotor are original; if they are, they're both the thick end of half-a-century old? If so, and price is not a factor, new stator and old rotor could be false economy.

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Originally Posted by TR7RVMan View Post
Seems be perfect time to upgrade to 3 phase. But, will the 3 phase still allow my bike to start with flat battery? I am using points


However, if you get a flat battery with a high-output 3-phase alternator, Something Is With high-output 3-phase, even my T160's old 11Ah, 90 ccA lead-acid batteries always had enough power to electric-start ... mind, they do have Rita e.i. instead of shonky old points ...

Btw, you know to buy "Made IN UK/England" stator 'n' rotor, not Wassell "Genuine Lucas" ? If Mitch Klempf doesn't have the former, check with John Healy who in the US does?

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Originally Posted by TR7RVMan View Post
what would you do for rectifier, regulator? Use the 3 phase rectifier & 3 zeners or what brand rectifier/regulator.
I'd go for a 3-phase reg./rec., either Podtronics or one of the cheap Ebay Chinese Honda ones. While you can still get good 3-phase plate rectifiers, the old T140E "3 zeners" are 'negative ground' only and NLA afaik; the old 'positive ground' arrangement was two 'matched' Zeners on the DC and they've been NLA for ages.

Quote:
Originally Posted by TR7RVMan View Post
What is most durable & trouble free in you experience?
I want the most reliable.
Well, the oldest of my T160's rectifier-'n'-matched-Zeners is now something like 36 years old ... Podtronics has been around since since God was a boy, the guy who put me on to the cheap Ebay Chinese reg./rec. ("NickL" on BritBike) posted he's been running his oldest for about eight or nine years?

The only other possible factor between the aforementioned reg./rec. might be size? I can post the dimensions of a Chinese Honda reg./rec. this evening or tomorrow, you might want to check how it compares to the size of a Pod?

Quote:
Originally Posted by TR7RVMan View Post
Or am I better off just replacing with what I have now?
All new rotors and stators are similar prices so high-output 3-phase stator is the most 'bang for your buck'.

BUT (and it's a J-Lo), ...

Quote:
Originally Posted by TR7RVMan View Post
(original type 415 headlamp).
Headlight on all the time as I always ride with headlight on.
... I'm wondering why you haven't changed the pilot bulb for an Eagle Eye LED off the 'Bay and use that in daylight?

If your bike has the standard pilot bulb, it's on with the headlamp, so that's 0.5A-ish wasted for nothing. Bear in mind one of the standard Eagle Eyes recommended by @rambo is a straight replacement for the standard incandescent pilot bulb and holder, and it has two wires for connection to the bike's -ve and +ve wiring. Either the 10W or the 20W Eagle Eye will put out more actual light than the shonky 415 headlamp bulb, and (assuming the 415 dip is 35W?) even the 20W is drawing less Amps than the headlamp.

Even if that doesn't fix the charging problem and you still need to shell out for new rotor, stator and reg./rec., worst-case the bike has gained a better daylight riding lamp?

Quote:
Originally Posted by TR7RVMan View Post
Shop manual states use good quality moving coil amp & volt meters. Is that really necessary?
The manual was written before digital meters.

Quote:
Originally Posted by TR7RVMan View Post
MY next task is get a proper 1ohm resister.
Pm "Magnetoman" on BritBike; some time ago, he suggested something more-modern and better, I just can't find the post and I've been meaning to pm him.

Hth.

Regards,

Stuart
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post #10 of 18 (permalink) Old 05-24-2019, 07:44 AM
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I have had several Triumphs recently with low voltage as Don describes....A new rotor solved the issue in both situations...Both bikes have Podtronics.....
My 79 T140D with the original Lucas three phase system charges at near 14 volts at idle and 14.5 above 2000 rpm...I also use a Podtronics on this bike because the original rectifier was shabby looking....

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