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Alternator Information


Alternator Specs.
Do you have a high current alternator to replace the stock alternator in my_____?

The general answer to this question, a frequent one that we receive, is shown below:

Dear ________,

We make 150 amp, 200 amp, 250 amp, and 240 amp MODULAR welding power generator units which can be used as ultra heavy duty replacements for automotive or marine alternators.

All models reach their maximum output current at about 6,000 rpm, and their most efficient operating speed range is between 5,000 to 7,000 rpm.

Depending on your engine crank pulley diameter, and the diameter of the drive pulley on the power generator, this typically equates to between 1,800 to 2,500 rpm in motor vehicle installations.
CLICK HERE for specifications.

In most automotive applications, particularly in emergency vehicles, or other vehicles which require a large amount of continuous power for on board electronic equipment, some sort of idle up system is usually installed and used to insure efficient generator operation. Marine applications may or may not require this sort of system.

High idle systems are available from ZENA for most work vehicles -- call for details.

Thanks to a unique design, multiple ZENA generator units (of like type) may be electrically and mechanically synchronized to produce very high welding (or charging) currents (300A, 400A, 450A, 600A, 800A, etc.).

All ZENA power generator models require heavy duty external voltage regulators when used as alternators ($55-$450 depending on features and application).

NOTE: When using multiple generator systems, in synchronized combinations, to produce higher amperages, extra control electronics will be required. Figure on about $450 for the first unit, and $200 for each other unit in the group.

The uni-directional (CW rotation) 12 volt 150 amp power generator unit sells for $350, a bidirectional model is $450, our 200 amp 12 volt unit is $695, and our externally rectified 240 amp and 250 amp models are $1155 (including external rectifier). An externaly regulated 200 amp model is also avilable as a special order item.

No ZENA power generator units are equipped with avalanche diodes.
If your vehicle requires an alternator which is equipped with this type of component, do not use one of our power generators as a replacement for this alternator without using one of our WC.OVP12 over voltage protection modules ($55).
However, you can safely use our alternators for supplying current to a secondary vehicle electrical systems as noted below without this accessory.

None of our basic generator units will likely be a direct replacement for a stock alternator -- in either size or bracketing/mounting.

As one would expect, most high current alternators ARE NOT direct physical replacements for low output stock units. However, if you have good fabricating skills, or if you have a mechanic with such skills, it is usually fairly easy to adapt these units to a particular engine. In most larger vehicles, and in most marine applications, it is also possible to install two generating units on your engine (doubling charging power).

When more than two units are to be installed in an automotive system, a hydraulic drive motor is usually the method used for driving the multiple power generators.

Marine and/or freestanding engine applications can often accommodate additional generating units without requiring a hydraulic drive system.

Our 150 amp generating units use a 2" mount/pivot point, our 200 amp model uses a larger 3" mount/pivot, our 250 amp model uses a J180 mount, and our 240 amp unit uses a version of an AD244/Vortec mount.

The ZENA 150 amp unit requires a mounting location with enough space to accommodate an object approximately 6-1/2" in length and 6" in diameter.

The ZENA 200A unit, which is about the size of a 2-1/2 lb. coffee can, is about 9" long and 6-1/2" in diameter. While it is almost always possible to fit the 150 amp unit in a given automotive application, the 200 amp unit which it is larger than the 150 amp unit, may require a bit more bracketing work to make it fit. 200 amp marine installations, typically present no such problem. If using our externally rectified version length is reducded by about 2-1/2".

The ZENA 240 and 250 amp units are about 7.5" in diameter and about 7.5" in length. Both models use an external rectifier assembly -- which improves performance and reduces the size of the component which must fit to the engine.

To check for size in your vehicle, we recommend that you make up a cardboard model using the size (noted above) of the model which you are interested in.

We sell all of our products with a money back guarantee, so if you find that they cannot be fitted, or if you don't like a unit for any reason, you can get a refund -- or upgrade/downgrade to the model that you need.


In most applications, IF space is available, using a secondary electrical system to supply ALL high amp components is, in our opinion, by far, the BEST solution to the problem.

This involves installing a SECONDARY high-amp alternator which charges a SECONDARY high capacity, deep cycle battery (or batteries). Thus creating an electrical supply circuit separate from the primary battery's electrical system, which is used to supply the electrical needs of all high amp nonstandard/special equipment installed on the vehicle (i.e., winches, high power audio systems, etc.).

Since this is also the best way to install welding equipment on a vehicle, our power generating units are designed to perform perfectly in this type of secondary electrical system. Best of all, we have developed bracketing accessories which will help you in fabricating a second alternator installation. We call this type of installation a piggyback installation, and it is the most popular method of installing our alternators when they are used for generating welding power.

CLICK HERE for a diagram of this type of installation.

We also have a number of pictures available which illustrate secondary alternator installations in welding applications. However, the same installation methods are used for secondary alternator installations.

CLICK HERE to go to our web site map for descriptions/links to the pictures available

If you are planning your piggyback installation into a vehicle with sufficient under hood room, and if you have a serpentine belt drive system for under hood accessories (alternator, PS, AC, etc.) consider the use of an easy to construct Add-A-Pulley accessory which provides a means to securely attach a second V-pulley in front of any existing alternator's serpentine pulley - providing an easy mechanism to drive the secondary alternator which is being installed. (Call us for instructions on how to build your own Add-A-Pulley.)

Our A300 and TBUCK bracketing accessories are also popular installation accessories, for 150 amp unit installations, and can further simplify the installation process.

NOTE: For 200 amp and larger units, we don't usually recommend generic bracketing accessories, as it takes less under hood space to custom fabricate all bracketing components for a given vehicle.

Finally, for a vehicle installation, you may want to consider adding our ASC1 automatic speed control (or one of our other automatic engine speed control accessories) to provide a means to increase engine speed when it is necessary to obtain full power from your alternator when the vehicle is stationary.

Hope this helps. Feel free to call if you would like more information, or if you want to discuss your particular application in more detail.

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