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

An engine (or other motor) capable of producing a minimum of 5.5 hp @ 6,500 rpm is required 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 -- electric drive motor -- Our 150A welders can be driven to maximum (or near maximum) output power by an 3,450 rpm continuous duty 5 hp electric motor for a short period of time. BUT, as welding power is produced for an extended period, a 5 hp electric motor heats up and looses power. Therefore, a continuous duty 7-1/2 hp electric motor is the practical minimum needed for 100% duty use. (In this case, we are assuming that the engine is equipped with a 6" drive pulley and that the power generator is equipped with a 3" shaft pulley -- a 2:1 pulley ratio.) CLICK HERE for more on electric drive welding systems for in shop use.
• 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 -- IF the engine is equipped with a heavy enough flywheel to insure the engine's ability to operate smoothly without loss of rpm under maximum load. (In this case, we are assuming that the engine is equipped with a 6" drive pulley and that the power generator is equipped with a 3" shaft pulley -- a 2:1 pulley ratio.)

NOTE: In some cases, when using single cylinder internal combustion engines, we find that extra horsepower is required to insure proper operation due to inadequate engine flywheel mass. Twin cylinder engines ranging from 16 to 20 HP have been used successfully drive 150A power generators without needing modification to the stock flywheel configuration.

Generally, our customers report that 14-20 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 welder drive engines. Kohler 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 very good power sources for 150A welders.

Small, 6+ HP diesel engines also make excellent power sources for 150A welders.

Our 200A power generators require approximately 50% more power than the 150A power generator (about 7.5 HP @ 6,500 rpm for direct drive). Otherwise, all of the comments above also apply to 200A power generators.

For example:

• If driving your 200A welder from a gas motor, expect to use an 18-22 HP, 2 cylinder gas engine.
• If using a small diesel, 8-12 HP should work quite well.
• If using an electric motor, you will need at least 10 HP @ 3,450 rpm.

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

NOTE 1:
Remember, when working with lower hp engines, flywheel mass must always be great enough to insure smooth operation under maximum load.

NOTE 2:
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 -- and often good transmissions as well.
They also tell us that a "riding welder" is an extraordinarily useful configuration. We agree, and often use this type of welder for marketing presentations and trade show expositions -- as well as for general maintenance work.
We do not have formal plans for this type of installation. However, we do have pictures and descriptions of such installations on our web site:

CLICK HERE for
pictures of a 150A riding welder

CLICK HERE for
pictures of a free standing 150A engine driven welder made using parts from an old 11 HP riding mower

CLICK HERE for
pictures of a worn out engine driven welder retrofitted/repaired with a 200A ZENA welder

ZENA™ is a trademark owned by ZENA, Inc. for its welding systems and related products.

US & Foreign Patents Pending

© Copyright 1998-2004 by ZENA, Incorporated. All rights reserved.