Rectifier / Condensor

[WINGS]

Hi have noticed a few people are using 2 rectifiers on their machines, is there any particular reason for this. The reason for asking is I have been running a 36MT60 3 phase rectifier for a number of years without any problems. The photo shows the setup I use. There are two of the 36MT60's on the heatsink giving a spare should the need arise.

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The condensors / capacitor I use are PME271M622K 0.22uf 275v in the setup below. The other setup (new in red) is using WIMA 0.22uf 630v the only reason on the change is I had to purchase 10 of the WIMA to use 1 to upgrade a chainsaw ( Stihl 031 av).
Steve

 

[retiredgentleman]

If you are using a 3 phase rectifier, then you only need 1 of those.

The alternator on the XS650 is a 3 phase alternator, so a 3 phase rectifier is needed. A 3 phase rectifier has 6 diodes inside it.

When lads say they are using 2 rectifiers, it means they are using 2 bridge rectifiers. Each bridge rectifier has only 4 diodes inside. Because there are only 4 diodes, you must use 2 bridge rectifiers....................6 diodes are wired up and 2 are not wired.

The use of 2 bridge rectifiers has become common because its an inexpensive way to make up a 3 phase rectifier.

Here' a pic of my rectifier, which uses 2 bridge rectifiers.

 

[WINGS]

Hi retiredgentleman I am aware the xs650 uses a 3 phase output, my curiosity was as to why 2 bridge rectifiers are used when a single 3 phase rectifier would suffice. I can appreciate cost becomes a significant factor, over here in the UK even used parts come at a premium sometimes rediculously so.
I chose to mount 2 3 phase rectifiers on the heatsink this gives a spare in place and simlpe switch of the wiring gets me on my way again with the minimum inconvenience.I adopted this after being stranded late at night in typical UK weather ( rain lots of it ) Ever since I have doubled up on most of the electrical components. I just need to source a cheap regulator.
Cheers
Steve

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[retiredgentleman]

Hi retiredgentleman I am aware the xs650 uses a 3 phase output, my curiosity was as to why 2 bridge rectifiers are used when a single 3 phase rectifier would suffice. I can appreciate cost becomes a significant factor, over here in the UK even used parts come at a premium sometimes rediculously so.
I chose to mount 2 3 phase rectifiers on the heatsink this gives a spare in place and simlpe switch of the wiring gets me on my way again with the minimum inconvenience.I adopted this after being stranded late at night in typical UK weather ( rain lots of it ) Ever since I have doubled up on most of the electrical components. I just need to source a cheap regulator.
Cheers
Steve

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Yes, its simply a matter of saving money. My 2 bridge rectifiers cost me about $12.00, and I just used an old heat sink that I had laying in my junk box. Compare that to the cost of a 3 phase rectifier, which seem to be around $50.00.
http://www.ronniesmailorder.com/dlr...dernumber_1264561-RICKS+3-PHASE+RECTIFIER.htm

Its certainly a good idea to carry extra parts in case of a break down on the road. I carry a spare set of points for the ignition, and actually had to use it when my electronic ignition had a screw vibrate loose. I changed out the ignition on the side of the road, and carried on riding. I now carry spare points and a spare electronic ignition when on long trips.

Looking for a cheap regulator......................have you tried to find NOS regulators from automobiles? I use the VR-115 regulator, which was used on 1970 era American Motors products and Jeeps. Cost me less than $20.00 including shipping. Search on E-bay.

 

[WINGS]

Hi I have looked around ebay for the VR-115 however the delivery charge tends to be twice as costly than the item itself ( average post comes in around 25 GB pounds ) so on average item plus post 50 GB pounds then a further 20 GB pound approximately for customs and admin fee from the postal service here in the UK. Thats around $150 total.
Will be looking on the internet for schematics with a view to building my own.
Cheers
Steve

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[XSLeo]

RG, have you searched Ebay for 3 phase rectifiers. I did and bought a couple to try. 25 amp, 1000 volts. I don't recall just how much I paid, I think it was around $5. They are on there now starting around $7. They have an aluminum case that I think will be enough heat sink, but bolting them to a larger heat sink won't hurt. Haven't gotten around to it though. I'll post pics. I was just browsing the Ebay listings and they do sell some that look like our bridge rec's but are 3 phase. Start around $8 and 35 amp, 1000 volt. I got the ones like the bottom pic.
WINGS another reason we chose the bride rectifiers is that Radio Shacks are very common here stateside. Easy to find and they often stock the rectifiers, so even on a roadside breakdown the parts are easy to find.
Also I think if you found a shop that rebuilds alternators, they may have a source for regs that will work. Just tell them you have a field excited alternator, they should know what that means. They might be able to tell you what cars used one. Not many new cars but plenty from the mid 60's to mid 80's. Before that mechanical, after controlled by the on board computer.
Leo

 

[pamcopete]

Being able to just go to your local Radio Shack is an incentive to use the dual full wave bridge rectifiers, plus only three of the four sets of diodes are used in our application, so you have a built in spare set of diodes, but even if you had to replace both of them, Radio Shack usually stocks them so that can make the difference between riding or not on a weekend, unless you carry a spare 3 phase rectifier.

The same for the two choices of automobile regulators. Both are available at most auto supply stores, and they carry a one year warranty, so that can also mean riding on Saturday or not.

 

[CDNTX650]

I also built my last one, and i went way over board on Rectifier size and bolted it to an aluminum switch plate without any paste, still cheap and as far as i know shes still goin strong 5 years later.

 

[retiredgentleman]

RG, have you searched Ebay for 3 phase rectifiers. I did and bought a couple to try. 25 amp, 1000 volts. I don't recall just how much I paid, I think it was around $5. They are on there now starting around $7. They have an aluminum case that I think will be enough heat sink, but bolting them to a larger heat sink won't hurt. Haven't gotten around to it though. I'll post pics. I was just browsing the Ebay listings and they do sell some that look like our bridge rec's but are 3 phase. Start around $8 and 35 amp, 1000 volt. I got the ones like the bottom pic.
WINGS another reason we chose the bride rectifiers is that Radio Shacks are very common here stateside. Easy to find and they often stock the rectifiers, so even on a roadside breakdown the parts are easy to find.
Also I think if you found a shop that rebuilds alternators, they may have a source for regs that will work. Just tell them you have a field excited alternator, they should know what that means. They might be able to tell you what cars used one. Not many new cars but plenty from the mid 60's to mid 80's. Before that mechanical, after controlled by the on board computer.
Leo

Leo, I just had a look on Ebay, and found some suitable 3 phase rectifiers for the ridiculous low price of $4.65. To make it even better, the shipping from China to Canada is free. If the quality is good that is a real bargain. The Chinese may have had to reduce the quality to sell them for $4.65.

The bridge rectifiers (NTE 5326) I use now, seem to be of high quality, with silver plated terminals.