Paralleling two alts...Do I need a equilizing conection?

[Spencerk 4]

OK I have made the decision to go with a custom dual alt set up in the Taurus...yada yada ya mount it, longer, belt, etc.. done. BUT I got to thinking about a few things I learned in school and I was wondering if anybody else on here with a dual alt set up has run a equalization connection between the two to prevent the alt that has the stronger field excitation from taking all the load and turning the other weaker one into a motor? And how do you know that both are in phase as not to double voltage when they are 180 degrees out of phase, 28 volts will fry my car.

anybody with knowledge of electron physics that could help would be GREATLY appreciated

[andymcdo 3]

I think you are overthinking dual alts big time. I've never heard of needing an 'equalizing connection' or them running out of phase. its dc power not ac. dc power, as far as i know, cannot run out of phase.

[Spencerk 4]

Well actually an alternator produces an alternating current or AC hence the name for the machine and the name for the sign wave formation of the voltage...the DC the is produced by way of a tri rectifier and diodes that in the most simple terms (much more to it of course) chops off the bottom half of the sign wave and gives you BAM!! DC voltage

[andymcdo 3]

Well actually an alternator produces an alternating current or AC hence the name for the machine and the name for the sign wave formation of the voltage...the DC the is produced by way of a tri rectifier and diodes that in the most simple terms (much more to it of course) chops off the bottom half of the sign wave and gives you BAM!! DC voltage

Ok. Hopefully someone else will chime in.

[CrazyKenKid 64]

you are correct alts make a/c power internally and output DC power, but this dc power is a fake and has ripples in it which should be smoothed out with a cap! but all that aside running duel alts is truely awesome!!

now to my knowledge an alt is similar to an generator as it takes machanical energy and converts it to electrical energy so the potential to get them out of phase or having the fields screw you up is potentail BUT very unlikely b/c keep in mind a/c looks like this ~~~~ while d/c looks like ---------- the only thing you NEED to worry about is to have the regulators set (if applicable) remebemer you will be hooking the 2 power supply up to the battery in parellel right so in a parellel setup what happens to voltage? similar to hooking up tobatteries if you hook them in parellel what voltage does your amp see? and if you hook them in series what does your amp see?

like both alts postives are still going to the same spot right! (front battery) and remember they will both spin at the same rpm as they will be hooked up the same belt!

now i am pretty sure that is correct i will doulbe check with my electrical teacher and see what he says! so let me get a corection on tis before you or anyone else give me a -1!

[andymcdo 3]

If they're internally regulated, something like an MLA module would keep them in sync with each other.

[Spencerk 4]

No would not give you a -1 your imput is appreciated...I was reading up in my book for one of my old magnetic / electron theory classed and I came across an article in their about this, so I poked round the net and came accross this ( Generator synchronization (John De Armond) ) and it was exactly what the book said.

[CrazyKenKid 64]

that is a good read!! very informative!!

so for you they will both be turning the same speed so they will be in sync with each other and in phase then? or did i read that wrong?

[andymcdo 3]

that is a good read!! very informative!!

so for you they will both be turning the same speed so they will be in sync with each other and in phase then? or did i read that wrong?

That's what I gathered from it. Being a mechanical engineering student, it takes me a little longer to figure out electrical stuff but I get it eventually.

[Spencerk 4]

that is a good read!! very informative!!

so for you they will both be turning the same speed so they will be in sync with each other and in phase then? or did i read that wrong?

Well yes they will be turning the same speed but when i put them in. I would have to some how make sure both pullys are in the same position and if the belt were to slip then they would be off or out of phase. I think....

[CrazyKenKid 64]

that is a good read!! very informative!!

so for you they will both be turning the same speed so they will be in sync with each other and in phase then? or did i read that wrong?

That's what I gathered from it. Being a mechanical engineering student, it takes me a little longer to figure out electrical stuff but I get it eventually.

lol iam studing to be an electrical engineer and it is our job to put you guys out of work! lol ask your teacher about that! (or maybe that is an ele engineer thing)

[CrazyKenKid 64]

umm good point make sure the tension on both alts is equal!! and if the belt slip off 1 you still have the other one but if it slips off both you have issue lol and your engine temp will rise lol and all kinds of issue will happen!

[altoncustomtech 773]

That article is still talking about AC generators, NOT DC output alternators. Yes an alternator creates AC voltage internally but the final product IS DC and does not have a PHASE to it. If you want proof that it's okay to hook them directly up in parallel go look at some of the under-hood photos available at some of the competition organization and such websites. I remember specifically in a Car Audio & Electronics magazine article a '86 Ford Bronco that competed in the 170+ class with two dozen alternators under the hood on a specially built plate. All the wires went directly from the alts to the buss bars on the ump-teen-hundred batteries in the thing. It was hands down the craziest electrical I've ever seen and I'm sure it took all that 460BB (or 490, or whatever monster big block ford had back in the day can't remember what the article said was in it now) had just to turn the alts under load.

Here's an introduction link to the article on the website. Alma Gates - 20th Anniversary 1986 Ford Bronco

[andymcdo 3]

Contact a reputable alternator manufacturer that does dual alts kits like mechman or dc power. I bet they can get you all the info you'll ever need.

[altoncustomtech 773]

Here's some pics under the hood of that truck. Alma Gate's Bronco

[NB50 206]

No would not give you a -1 your imput is appreciated...I was reading up in my book for one of my old magnetic / electron theory classed and I came across an article in their about this, so I poked round the net and came accross this ( Generator synchronization (John De Armond) ) and it was exactly what the book said.

There's a problem that is talking about AC generators not DC. Yes your alternator creates an AC waveform, in fact three of them, then converts it to DC. If you were to measure the AC output before the rectifier it would have three waveforms about 45* out of phase of each other. It will look something like this.

After you convert AC to DC there is no phase.

[CrazyKenKid 64]

holy wires batman!!

[altoncustomtech 773]

If you notice, they have several alternators all wired to each other parallel before it goes to the big buss bar on the side.

[andymcdo 3]

No would not give you a -1 your imput is appreciated...I was reading up in my book for one of my old magnetic / electron theory classed and I came across an article in their about this, so I poked round the net and came accross this ( Generator synchronization (John De Armond) ) and it was exactly what the book said.

There's a problem that is talking about AC generators not DC. Yes your alternator creates an AC waveform, in fact three of them, then converts it to DC. If you were to measure the AC output before the rectifier it would have three waveforms about 45* out of phase of each other. It will look something like this.

After you convert AC to DC there is no phase.

That's exactly what I was thinking, couldn't put it into words though.

[CrazyKenKid 64]

that is it i am pulling my oscope out to verify there is no ripples and it is 100% straight lol! jk!!!

[Spencerk 4]

That article is still talking about AC generators, NOT DC output alternators. Yes an alternator creates AC voltage internally but the final product IS DC and does not have a PHASE to it. If you want proof that it's okay to hook them directly up in parallel go look at some of the under-hood photos available at some of the competition organization and such websites. I remember specifically in a Car Audio & Electronics magazine article a '86 Ford Bronco that competed in the 170+ class with two dozen alternators under the hood on a specially built plate. All the wires went directly from the alts to the buss bars on the ump-teen-hundred batteries in the thing. It was hands down the craziest electrical I've ever seen and I'm sure it took all that 460BB (or 490, or whatever monster big block ford had back in the day can't remember what the article said was in it now) had just to turn the alts under load.

Here's an introduction link to the article on the website. Alma Gates - 20th Anniversary 1986 Ford Bronco

HOLY $HIT I googled that truck wow thats like a few thousand amps of juice!!!! I know that TONZ of people have done this so I know its possible but I want to make sure I do everything by the book. I will be in contact with mech man to verify, I just was wondering if anyone here knew anything about this. thank you for all of the imput gentleman

[Spencerk 4]

WAIT BUT THERES MORE!!! so last night I was looking at dual alt kits and they all come with some sort off a relay. What is this for?? from what I have read about them you cant just hook them up in parallel but nothing states why you cant. Read the Middle picture second one from the bottom.

( http://www.caraudiomag.com/technical/0206cae_dual_alternator/index.html )

Edited February 3, 2010 by 144dbFiBl15

[andymcdo 3]

Well according to the article, its to isolate the two charging systems. But since you're not doing this I think you just have to tap into the factory plug from the primary alternator and wire it into the second alternator so it knows what to do.

[altoncustomtech 773]

Exactly, that's for running a second alternator to separate the car's electrical from the audio electrical. The relay is used to disconnect the trigger lead on the alternator so it doesn't run the battery down. Since you're just wanting to parallel the alts, it doesn't apply to your particular agenda. You'll be just fine hooking the alts up in parallel. I've seen quite a few service vehicles (ambulance's, fire trucks, etc.) that use dual alts paralleled with nothing special on them as well.

Edited February 3, 2010 by Alton