Remote Rectifier For The Largest Alternators

[MEXICOWANDERER]

Bolt One Of These


http://www.ebay.com/itm/Bridge-Rectifier-3ph-300A-1600V-MDS300A-diode-3-phase-300-amp-1600-volt-1-PC...

Onto one of these...


http://www.ebay.com/itm/Large-Extruded-Aluminum-Heatsink-8-3-16-x-5-1-8-x-1-7-8-inches-/131325481652?pt=LH_DefaultDomain_0&hash=item1e939bd2b4

And mount it a few feet away from your house batteries. Have an alternator rebuilding shop join three six gauge wires to an alternator's 3 stator wires, and presto. 40% of the heat in the alternator goes away. Presto. 80% of the voltage drop between alternator and house batteries vanishes. This is an automatic battery isolator device. And this unit is oversize even when coupled to a 270 amp alternator.

[Naio]

Well this looks VERY interesting!

[MEXICOWANDERER]

Three phase battery chargers are insanely expensive

GOOGLE search SCOTT CONNECTION TRANSFORMERS

This will suck on all three phases equally and render single phase 120 or 240.

Then use a charger or multiples like a Vector, Megawatt, et. al.






three

[Orcadrvr]

Okay, now I get it.

I sure learn a lot on these forums. Thanks for the explanation.

Not certain how to gift wrap this thing for my wife, though!

By the way, would it be possible to use these rectifiers to change the output from one of those big diesel three phase generators to DC, then run it through an inverter, and make your own inverter generator? California is apparently forbidding the use of the older ones for commercial purposes, and you see a lot of them on Craigslist and so forth.

Thanks again for the info.

[Bend]

Orcadrvr wrote:
...
Why do we want to rectify an alternator?

So I no longer need to haul, care for, feed and babysit a 35+ pound genset and yet decrease the impact on my TV's charging system when charging house batts while boondocking.

Yes, I have solar. However, there could be/are times when it just can not keep up with demand.

[MEXICOWANDERER]

Bend, yes, exactly. The capacitance is within the amplitude (voltage) and time (frequency) requirements. The recommended threaded hole for mounting is 6-32

Mister Wizard's answer is smack dab dead-center.

In addition...

The rectifiers in today's alternators are horribly stressed right to the bitter limit of amperage - except the alternators to not operate at the balmy temperatures that the rectifiers are rated for. No. They have to operate in conditions a hundred and fifty to two hundred F higher. Sort of like asking a Load Range E tire to operate at maximum load on two hundred fifty degree concrete.

When Big Al sold Renard Rectifier and Frank Oropeza sold Transpo Electronics to WAI, the era of buying optional heavy-duty alternator rectifier bridges faded. The golden era is gone.

Some idiot School Bus maintenance shop decided to spend four thousand dollars on an 8-9/16" frame 400-amp Niehoff alternator for a Crown bus then sold the bus because the district was offered Blue Birds.I lucked out. But I manufactired an absurd remote rectifier using 1,200 ampere 1,675 PIV rectifiers. Stud rectifiers with eight-inch long 2/0 leads with 1/2" holes and 7/8" studs. The stator studs on the alternator are 5/16". Copper 1/2" pos & neg studs. The Niehoff has two fans: an exterior rear fan and an exterior front fan. Brushless.

When a rectifier fails open or shorted the stator will overheat and fail.

It's nice to have voltage at the house batteries within a few hundredths that at the alternator output studs.

A Power Post Princess does not need an external rectifier. A boondocker would surely benefit by one. Bokndockers make frequent gasoline and grocery runs.

[MrWizard]

old DC car generators had heavy brushes, and worn out frequently

car alternators have 3 phase windings, 3 outputs of AC electricity that is rectified internally by 6 diodes to make a smoother DC.

those diodes create a lot of heat, the internal voltage regulator compensates by reducing the power output, to keep the alternator working

connecting directly to windings feeding those diodes, bring that high frequency AC power to a set of external diodes, use the external diodes to rectify the power to charge the RV house batteries
reduces the heat load on the internal alternator diodes and windings

you get a longer life for the alternator, and more power higher charging voltage into the house batteries

[Orcadrvr]

So, I'm not (by a large margin) the smartest electrical guy on these forums.

But, I've been reading these posts and don't have a clue what this device will do for me. I am consumed with curiosity, and before I buy one for my wife for mother's day, I need to know what it does and why I, I mean she, needs it.

Why do we want to rectify an alternator?

thanks

[Bend]

Seems going old school with a car/truck point ignition condenser might be the ticket. Although uF & voltage ratings are hard to find:

http://www.amazon.com/ACDelco-D204-Professional-Ignition-Capacitor/dp/B000C9Q1TS/ref=pd_sim_auto_4?i...

Mount the body on the DC neg output and the wire on the pos output of the remote rectifier to parallel the charging wires?

[MEXICOWANDERER]

Nooooooooooooooooooo
Those are alternating current caps. Look for a

ELECTROLYTIC RADIAL CAPACITOR.

When you are winding or twisting the three stator feed wires I would incorporate a single 18-gauge wire twisted in with the three wires. Ground ONLY one end of the 18-gauge wire. To the battery negative of the house bank.

If the alternator generates electronic noise, connect
01 uf mica caps across the stator wire input at the remote rectifier.
1-2, 1-3, & 2-3

[Bend]

Will either of these work?

http://www.amazon.com/Ceiling-Capacitor-CBB61-2-5uf-500VAC/dp/B0087YS440/ref=sr_1_fkmr3_1?ie=UTF8&qi...

http://www.amazon.com/Ceiling-Capacitor-CBB61-450VAC-Wire/dp/B008DEZHT4/ref=pd_sim_sbs_indust_3?ie=U...

[MEXICOWANDERER]

That's a great pair to draw to. I would tend to recommend Arctic Silver as a thermal interface. A two microfarad 400+ volt capacitor must be attached to the DC connections of this rectifier.

[jrnymn7]

Yesterday, I saw a 120w folding solar kit on eBay for nearly $1,200.00!!! lol.

[Bend]

USA sourcing:

http://www.amazon.com/Bridge-Rectifier-1600V-MDS400A-diode/dp/B00JES7ZQ6

http://www.amazon.com/10-000-Extruded-Aluminum-Heatsink/dp/B00OYF9XU0/ref=pd_sim_sbs_indust_5?ie=UTF...

http://heatsinkusa.com/

[MEXICOWANDERER]

Wotta hoot. In 4-months since I posted the link the vendor jacked the price around 900% !!!

I gotta stop laughing.

Don't forget these critters have got to be clamped to a LARGE aluminum fin heat sink. I use ball bearing fans. Full wave bridge two stator terminals and the fan only spins when the alternator is charging. A proper heat sink for 300-amps would measure 6"x 12" and have six horizontal fins. With a fan, 4"x8".