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High Amp Marine Alternator Specifications


ZENA¨ DC Power Generators

SR150, SR200, and SR250 Series Modular Power Generators
(used as replacements for conventional marine alternators)

Charging Power Output in 12V Electrical System (13.8V - 14.5VDC nominal) Series 150 --> 150 amps. (View Output Curve)

Series 200 --> 200 amps. (View Output Curve)

Series 250*--> 250 amps. (View Output Curve)

(mounted per recommendations with no obstruction to flow of cooling air)

Series 250 requires ZENA model ER350 external full-wave rectifier assembly

Charging Power Output in 24V Electrical System (27.6V - 29VDC nominal) Series 150 --> 80 amps. (View Output Curve)

Series 200 --> 125 amps. (View Output Curve

Series 250 --> 140 amps. (View Output Curve)

(mounted per recommendations with no obstruction to flow of cooling air)

Series 250 requires ZENA model ER350 external full-wave rectifier assembly

Minimum Drive Engine Power / Torque Requirements Series 150 --> 11 hp (Gas), 8 hp (Diesel)

Series 200 --> 16 hp (Gas), 11 hp (Diesel)

Series 250 --> 22 hp (Gas), 14 hp (Diesel

Series 150 --> (View Torque Curve)

Series 200 --> (View Torque Curve)

Series 250 --> (View Torque Curve)

Case Dimensions Series 150 -- 6.5" W x 8.5" H x 7" D
(See Series 150 Illustration)

Series 150B -- 6.5" W x 8.5" H x 9" D
(See Series 150B Illustration)

Series 200 -- 6.5" W x 9.5" H x 10" D
(See Series 200 Illustration)

Series 250 -- 7.5" W x 9.5" H x 9" D
(See Series 250 Illustration)

Series ER350 External Rectifier -- 6" W x 4.5" H x 9" D

(Clear space clearance requirement -- including pulley, terminals, and mounting lugs)
Minimum Shaft Speed for Maximum Output Power Approximately 6,500 RPM (higher shaft speeds up to approximately 16,000 rpm - have no detrimental effect on performance)
Minimum Shaft Speed for Minimum Output Power Approximately 1,500 RPM  
Direction of Rotation Series 150 -- Clockwise Rotation

Series 150B -- Bidirectional Rotation
(Clockwise Typical -- Hi-Efficiency Clockwise Option Available)

Series 200 -- Bidirectional Rotation
(Clockwise Typical)

Series 250 -- Bidirectional Rotation
(Clockwise Typical)

Series 150B, 200 & 250 NOTE:
When operating a 150B, 200 or 250 series Generator in CCW rotation mode, a thread-locking chemical adhesive should be used to insure Power Generator Drive Shaft Nut to Drive Shaft fastener connection integrity.
Optionally, for high vibration applications, an anaerobic stud/bearing fixing adhesive can also be used to insure secure and continuous, Drive Pulley to Cooling Fan and Drive Pulley to Power Generator Drive Shaft Nut contact.

Generator Cooling High Efficiency Forced Air, External Fan (rear to front air flow)

An auxiliary electric forced air cooling system is available that will allow ducting of cool air from outside a hot engine compensating to the rear of the generating unit. Highly recommended for applications where overheating is a potential problem

Expected Minimum Time Before Moving Component Failure 40,000 hours
Periodic Maintenance Requirement None -- other than cleaning, as necessary to remove oils, chemicals, and/or corrosive materials in cases where maintaining a clean operating environment is not possible. NOTE:
Cleaning (mild dish washing soap with fresh water and/or compressed air) may be required if operating in very dirty conditions, or if chemical contamination occurs.
Rotor Current Required
(for Full Power Charging)
12 volts -- 7 amps. maximum
24 volts -- 4 amps. maximum
Voltage Regulator Type Required

ANY A Circuit, or B Circuit (or type N, or type P) high current solid state external voltage regulator


a ZENA model WC.VR Universal Voltage/Current Regulator used in combination with one, or more, ZENA WC.12 Power Control Modules


a ZENA model WC.VR2 Universal Voltage/Current Regulator (w/ Over Temperature Sensing) used in combination with one, or more, ZENA WC.12 Power Control Modules


a custom designed OEM control system conforming to guidelines provided by ZENA, Inc.

In applications where long term high current demands exist, and/or where very large battery banks are in place, and/or where batteries with very low battery impedance loads are employed, active protection methods should be employed. Such devices include regulators which limit maximum charging current and/or sophisticated voltage regulators which monitor and regulate alternator temperature (such as our ZENA model WC.VR2), output/charging lead temperature, and battery temperature should be employed.
Tachometer Signal Output

(Available as an Extra Cost Factory Option)
150 Series --> Available (+US$50)

200 Series --> Available (+US$60)

250 Series --> Available (+US$65)

Tachometer Output can be in the form of EITHER an AC Stator Tap, a rectified + Stator Tap, or a rectified - Stator Tap.
Signal output is an insulated #10 terminal post installed on the rear of the generator case (un-fused).
Check with your tachometer manufacturer to determine the sort of signal expected for proper operation.
Suggested Retail Prices

(Shipping cost NOT included)
SR150.12 --> US$350

SR150.24 --> US$400

SR150B.12 --> US$450

SR150B.24 --> US$505

SR200.12 --> US$675

SR200.24 --> US$740

SR250.12 & ER350 --> US$1,105

SR250.24 & ER350 --> US$1,225

Both 12VDC and 24VDC output models are available with either 12V OR 24V rotor assemblies (an extra cost option).

This allows, for example, the use of ZENA welders in vehicles with 24V electrical systems OR the mounting of 24V charging systems on engines with 12V electrical systems.

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ZENA power generators are manufactured in the USA by ZENA, Incorporated and are sold with a three year limited warranty. We also have a unique guaranteed overhaul/rebuilding cost policy.

You have no risk if you order on-line, all units are sold with a 60-day money back guarantee of satisfaction.

ZENA® is a trademark owned by ZENA, Inc. for its welding systems and related products.
US & Foreign Patents Pending
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