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How large of an engine or motor do I need to drive a ZENA alternator/charging system?

An engine (or other motor) capable of producing a minimum of 6.5 hp @ 7,000 rpm is required to directly drive the 150A ZENA power generator.If using pulleys and a V-belt to drive the power generator, as is usually the case when the power generator is attached to a drive engine, the ratio of the pulley diameters used will effect the minimum engine hp and speed specifications.

Example 1 -- Diesel Engine -- Our 150 amp alternators can be driven to maximum output power by a 7 hp conventional liquid or air cooled electric start diesel engine. Note that there are small air cooled fast turning diesels on the market (most of which are made in China) which do not produce much more torque than a conventional gas engine. If using this type diesel a minimum of 11 hp will likely be required.

Example 2 -- Internal Combustion Engine -- A typical 11 HP, electric start, gasoline fueled, 4-cycle engine (horizontal or vertical shaft) which produces its rated maximum horsepower at approximately 3,500 rpm, can be used to drive our 150A power generator. Slightly smaller engines have also been successfully used to drive our 150 amp alterantor -- IF the engine was equipped with a heavy enough flywheel to insure the engine's ability to operate smoothly without loss of rpm under maximum load.

Generally, our customers report that 13-20 HP gasoline engines (which are usually factory equipped with electric start and with built-in alternators) of the type often found on riding mowers generally make good drive engines. Kohler, Robin, and Onan engines reportedly do particularly well, since they are frequently factory equipped with heavier flywheels. And, we have had many customers report that Honda's electric start 11 HP (and larger) engines make exceptionally good power sources.

Our 200A power generators require approximately more power than the 150A power generator (about 9 HP @ 7,000 rpm for direct drive). Otherwise, all of the comments relating to our 150 amp model also apply to our 200 amp models.

For example:

If driving one of our 200 amp alterantors from a gas motor, expect to use a 16 hp (or larger), 2 cylinder engine.

If using a small diesel, 10 HP (or larger) should work quite well to drive a 200 amp unit.

If driving one of our 240 or 250 amp alterantors from a gas motor, expect to use a 22 HP (or larger), 2 cylinder engine.

If using a small diesel, 13 HP (or larger) should work quite well to drive a 240 or 250 amp unit.

Feel free to call us for specific information and recommendations -- or, if you have questions about a specific application that you have in mind.

Remember, when working with lower hp engines, flywheel mass must always be great enough to insure smooth operation under maximum load.

Customers report that there are many very inexpensive used riding mowers on the market which have worn out mowing equipment, but which have perfectly good engines.


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