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Like any other components in car audio- alternator component beefyness counts. Alternators, like the voicecoil of a Subwoofer, are subjected to MASSIVE amounts of heat, strain and vibration. The heavier duty your components are, and the larger the alternator is, the better it will be able to dissapate heat. Furthermore, the more amperage the alternator produces, the larger the conductors need to be in order to physically transfer current without measurable loss.
The following picture compares two rectifier assymblys. The one on the left came off of a well known brand of High output alternator. Notice the physically smaller anodized blue aluminum rectifier plate. The MechMan unit on the right has a noticably thicker solid lazer cut copper rectifier plate, capable of dissapating much more heat, and conducting more current with less resistance. We all know how much better of a conductor copper is than aluminum. you will also notice a difference in the plastic covering the diode connections. Ours is much higher temperature, and physically larger. It may be hard to see, but the diodes in out rectifiers are much heaver, over .080 larger in diameter; 70 amp rated instead of 30 amp rated.
In another picture, we can see the huge difference in output posts. While it might seem like a simple upgrade, the charge post is responsible for carrying the full output of the alternator, which can easily exceed 300 amps. Running multiple runs of 1/0 cable seem almost pointless when the ouput stud itself is so small. Many car audio competitors have even had their output studs break off simply from the weight of 1/0 cable!! Under dyno testing conditions at full output, I have seen smaller output studs from other companies reach in excess of 400 degrees because they are too small. -NOTE- Larger charge posts are not available on all MechMan alternators. Some units have a samller charge post that is integral to the recitfier plate, and subsequently does not have overheating issues.
Here's another shot of our GM offerings. Our Rectifier is almost twice the thickness of our competitors in this case. The black rectifier on the left is on a popular brand unit that is claimed to produce 380 amps, but only managed to put out a peak of 288 amps on our dyno.
Our pictured unit on the right is one of our 250 amp rated StreetBeat units, and it actually made 271 amps on the same dyno.
The stator, or fixed windings of the alternator are responsible for determining the output curve of the alternator, and also what created most of the heat in an alternator. If you have ever smoked an alternator, chances are that the smoke was coming from the varnish on the stator windings burning off. This typically occurs around 350 degrees. It is important to know that any alternator stator (including MechMan) will burn if the alternator is abused or run at maximum output for too long. Our stators are built with the highest temperature components and highest grade copper available, but are still suseptable to failure if abused by the customer. This is why it is so important to monitor voltage when playing your system. If batteries are ever run down, the MUST be charged up with a battery charger before the vehicle is started. Also, a vehicle's voltage should never be run down below 13V with the engine running for more than a couple minutes at a time. The system needs to be turned down for a few minutes in order for the alternator to catch up and cool down.
The Rotor is the spinning portion of the alternator. It creates a magnetic field when energized, the when spun inside of the stator windings, causes electrons to flow through the stator, this is how an alternator converts mechanical (spinning) energy into electrical current. The stator on the left is an example of a "re-wound" stator, and a poorly executed one at that. Notice how not all of the rotor is "filled" up with wire, and it is haphazardly wound like a fishing reel. This wastes space, decreases the magnetic field, and subsequently the performance of the rotor, especially at low RPM. Most high output alternator companies don't even bother trying to wind a rotor, and utilize a stock rotor. Improved rotors are very expensive, (especially if done properly) and require other components of the alternator to be upgraded as well. Notice the clean, new windings of the MechMan rotor on the right.
Internal components are just the beggining of what sets MechMan high output alternators apart. Most midsize, compact, and import vehicles come equipped with very small alternator housings from the factory. Auto manufacturers have designed the smallest, lightest alternators possible in an effort to conserve weight and fuel economy. Modern import alternators are very efficient for their size, and cannot be easily improved upon like the simplistic domestic alternators of 20 years ago. The only way to increase the output on most small case alternators results in decreased output at lower RPMS. All other alternator companies rely on this technique because it is cheap and easy. This is why so many people who have bought high output alternators from other companies expierience low voltage or poor performance at idle- Most times they have less low RPM output than a stock alternator!!
MechMan units are built completely differently. We have a full CNC machine shop in house, where we mass produce custom machined LARGE case units that have the same mounting specifications as the factory small case alternator. By going to a physically larger, late model efficient alternator design, we can achieve massive output (250+ amps) while still maintaing brutal idle RPM performacnce. (over 150 amps) In addition, larger internal components can be used which dramatically increases full temperature performance and durability through heat dissapation that can be in excess of a 400% improvement of small case units. The picture below illustrates the dramatic difference between out units, and a competitors "150 amp" offering on the left. With no surprise to us, the brand X unit on the left barely mustered 5 amps at idle, with only 123 amps peak. Our unit on the right made 161 amps at idle with 268 amps at cruising speed- BOTH OF THESE UNITS FIT THE SAME VEHICLE. Notice the 1/0 included copper terminals for Positive and Ground cable connections. The grounding point is pressed directly into the alternator case to give the best possible grounging point. What good is making amperage if you can't get it to the battery??
Again, it doesn't take any special alternator knowledge to know the our unit on the right is going to be able to make WAY more current with much better durability. The tiny components on the unit on the left will simply melt if subjected to daily abuse. (assuming that you rev it up to get any output whatsoever) This is just one example of our 1,200+ large case conversion kits, all of which replace the existing small case alternator with a physically larger unit. This requires a custom machined housing, a plasma cut adapter bracket (in some cases) and an adapter harness that allows the stock alternator wiring to plug right in. Obviouslly, the unit on the right is going to cost more to build, but in many cases will sell for the same price as the high ouptut unit from one of our competitors that is based on a small or medium sized (cheap) alternator housing.
Even on fullsize doestic vehicles, we ONLY use large case units for Street Beat and higher models, because it is the only way the customer will be happy with the way the unit performs. Other companies just sell the unit cheap, and hope that the customer never gets ahold of a DC amp clamp capable of measuring the alternators actual output. Below is an example from a full size ford Truc. In addition to being larger in size, the MechMan unit is actually a late model, more efficient design that will run cooler and last longer. We even include an adapter harness so that the old wiring can be retained.
As you can see, we do things very differently here at MechMan Power systems. Most of the time, our units are priced BELOW the competition, even though our units require much more labor and cost to build. The end result is a far superior product, that actualy goes above and beyond it's advertised benifits.
It is not an issue of our unit working better than our competitors unit, is an issue of the customer recieving a product that accomplishes what it is supposed to.
Here are some shots of our dyno room. This is where every alternator we sell undergoes a fully automated test session that meassures ouput under varying load from 0 to 12,000 rpm rotor speed. We then take the unit up to 16,000 rpm for a couple minutes to make sure that everything seats properly, and any component failures occur and are rectified BEFORE the customer gets the unit.
Our alternator dyno is highly sophisticated, and measures everything from thermal loss, to horsepower input, to individual component temperature. We even have a thermostatically controlled oven the we place over the alternator that simulates hot under-hood conditions for extended durability testing.
The two units pictured here are our signiture StreetBeat Large case GM units equipped with out adjustable voltage feature. This allow the customer to set charging voltage wherever desired. (13.5 to 18.5 volt range) This can be ordered on any of our units with the external adjustable regulator option for only $99 aditional, but is especially convinient on the GM units because it is adjustable on the alternator case itself with no external regulator or wiring required.
For systems utilizing 12 volt AGM batteries, we typicaly set the regulator to 15.2 volts cold, which settles in to about 14.9 volts at full operating temperature. This is the maximum reccomended charging voltage for AGM batteries. Flooded type conventional batteries can be safely charged around 15.3 volts wihtout damaging them. The increased voltage results in higher amplifier efficiency, and a better charge state for the batteries.
The screen demonstrates the full output curve from idle on up to 8,000 rpm rotor speed, and will be printed out and placed in the box with the unit for the customer to review. It is important to remember that the RPM on the dyno displays ROTOR rpm, not engine RPM. Most vehicles have a 3:1 alternator pulley ratio, which means the alternator spins three times faster than the engine. In other words, 800 engine RPM would have the alternator spinning roughly 2,400 rpm. You can easily calculate your exact pulley ratio by dividing the diameter of your crank pulley by the diameter of your alternator pulley. For example: a 6" diameter crankshaft pulley divided by a 2" alternator pulley = 3:1. Most MechMan units are shipped with a 1.75" pulley.
Pics Temporarily removed......Mechman contact me for info - thanks!
This post has been edited by meade916: 19 November 2008 - 07:35 PM
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