Prestolite Alternator 24V 55A 66021507S

The Prestolite Alternator 24V 55A, part number 66021507S, is a new alternator supplied as each unit and built for 24 volt electrical systems. It is rated at 55 amps, uses an internal regulator, and is listed with an insulated return and field isolation. That combination makes the unit suitable for applications that require the stated Prestolite configuration rather than a universal replacement.

Key physical details matter on an alternator like this. The mount is a single leg style, with a 76mm mount leg thickness, 180mm mount centre-to-centre, a 9mm adjusting hole, and a 10mm pivot hole. The shaft diameter is 19mm, and the unit weighs 6kg, so confirming the mounting arrangement and drive connection before ordering is important.

This alternator is described as replacing AC5 and is marked for Prestolite unit applications. The listed features include above-ground construction, high temperature grease and seals for longer bearing life, and a fan design intended to improve air flow and support cooler operation under high output load conditions. It also carries a one year warranty.

Key Features

• 24V alternator rated at 55A
• New unit, supplied each
• Internal regulator
• Single leg mount
• Insulated return and field isolation
• Replaces AC5

Specifications

• Part No.: 66021507S
• Brand: Prestolite
• Type: Alternator
• Voltage: 24V
• Power Rating: 55 amp
• New / Reman.: New
• Unit of Measure: Each
• Warranty: One Year

Application and Buying Notes

Before ordering, check the part number 66021507S against the existing unit and compare the mounting details carefully. The key identifiers here are the 24V system, 55A output, single leg mount, 76mm mount leg thickness, 180mm mount centre-to-centre, and the 19mm shaft diameter. If any of those dimensions differ from the unit being replaced, the alternator may not suit the application.

The note ‘Insulated Return’ and ‘Field Isolation’ is important for compatibility. This alternator is not just a generic 24 volt unit; it is listed with those electrical characteristics and with an internal regulator, so the vehicle or machine needs to match that arrangement. The listing also states it replaces AC5, which can help when cross-checking the old part number.

Because alternators can vary by bracket layout, pulley arrangement, and charging system design, it is worth verifying the adjusting hole diameter of 9mm and pivot hole diameter of 10mm before purchase. The supplied weight of 6kg can also help when comparing against the removed component, especially when the original identification is unclear.

The listed features are practical rather than decorative: high temperature grease and seals are intended to support bearing life, and the fan design is aimed at air flow under high output load conditions. Those are useful construction details, but they do not replace a proper fitment check against the existing Prestolite application and the vehicle or machine’s charging setup.

Before supply, the safest approach is to confirm the original unit details against the listed part number, voltage, output rating, mounting arrangement, and pulley configuration. That checking process is standard practice in the parts trade because visually similar units can still differ in service-critical ways.

For workshop, fleet, and equipment applications, accurate identification of part number 66021507S helps avoid unnecessary freight, additional labour, and vehicle or machine downtime. Where the application is not straightforward, the original unit, OEM reference, or workshop records should be used as the primary confirmation point.

Relevant published details for this unit include Type ALTERNATOR, Unit of Measure EACH, Warranty One Year, Mount Leg Thickness 76mm, Power Rating (Amp) 55, Shaft Diameter 19mm, Voltage 24, Alternator Mount Single Leg, New / Reman. New, Weight 6kg.

Additional published details for cross-checking include Product Group 1 ROTATING ELECTRICAL, Part No. 66021507S, Brand PRESTOLITE, Description Prestolite Alternator 24V 55A, Adjusting Hole Diameter 9, Pivot Hole Diameter 10, Regulator Type Internal, Suits Unit Make Prestolite, Note Insulated Return. Field Isolation. Replaces AC5, Mount Cnt to Cnt 180mm.

Prestolite Alternator 24V 55A. Part number 66021507S should be checked first. Listed voltage is 24. Listed output rating is 55. These details form the core reference points used by parts interpreters when confirming the correct replacement.

Mount style is Single Leg. Regulator type is Internal. Those physical and electrical details should line up with the original unit before the replacement is approved for fitment.

For part number 66021507S, the normal identification sequence is part number, electrical rating, mounting arrangement, connector or terminal style, and pulley or drive details. Using those checkpoints helps confirm that the listed unit matches the service requirement rather than only looking similar.

For a alternator in workshop, fleet, trade, agricultural, or construction service, the listed voltage 24 and output 55 should be checked carefully. Incorrect selection can affect installation time, return freight, and equipment availability.

Where no verified application list is available, the part number, mounting details, connector style, and published specifications should be used as the primary selection criteria.

In the absence of a verified fitment list, the safest approach is to compare the removed unit directly with the listed product details. That includes checking the housing style, pulley layout, regulator arrangement, and any visible identification numbers before supply is approved.

The listed warranty is One Year. Warranty terms should be considered alongside correct application and part identification, as warranty does not replace fitment confirmation.

Compatibility note: Confirm compatibility by matching part number 66021507S, the 24V 55A rating, single leg mount details, shaft diameter, and the insulated return / field isolation configuration against the existing alternator and application.

FAQ

What is the part number for this alternator?

The part number is 66021507S.

Is this alternator new or remanufactured?

It is listed as new.

What voltage and output does it have?

It is a 24V alternator with a 55 amp power rating.

Does it use an internal regulator?

Yes, the regulator type is listed as internal.

What mounting details are provided?

The alternator has a single leg mount, 76mm mount leg thickness, 180mm mount centre-to-centre, a 9mm adjusting hole, and a 10mm pivot hole.

What should I check before buying?

Check the part number 66021507S, the 24V 55A rating, the single leg mounting setup, the 19mm shaft diameter, and the insulated return / field isolation configuration against the unit being replaced.