Prestolite Alternator 24V 155A AC172 Part No. 1277A740

The Prestolite Alternator 24V 155A is a new rotating electrical unit in the AC172 series, identified by part no. 1277A740. It is designed as an above ground alternator with an internal regulator, twin leg mount, and insulated return, making it a straightforward replacement option where those exact details are required.

This unit is rated at 24 volts and 155 amps, with a shaft diameter of 30mm, shaft dimension of 30, and a mount centre to centre measurement of 210mm. The inside mounting legs measure 111mm, while the adjusting hole diameter and pivot hole diameter are both 16mm, so matching the physical mounting points is essential before ordering.

A key point with this alternator is the bi-directional rotation and remote sense arrangement. It also uses high temperature grease and seals for longer bearing life, and a fan design intended to improve airflow and support cooler operation under high output load conditions. The alternator weighs 16.2kg and is supplied as each.

For buyers working on applications that use Prestolite charging equipment, the combination of 24V output, 155A capacity, internal regulation, and part no. 1277A740 provides the main identification points. The pulley section is not applicable, so belt and pulley setup should be checked against the vehicle or machine application before installation.

Key Features

• New alternator
• 24V, 155A output
• Internal regulator
• Bi-directional rotation
• Remote sense
• Above ground design

Specifications

• Brand: Prestolite
• Series: AC172
• Part No.: 1277A740
• Product type: Alternator
• Voltage: 24V
• Power rating: 155A
• Mount type: Twin leg
• Inside mounting legs: 111mm

Fitment and application notes

• BCI Citirider
• BCI Classmaster
• BCI Fleetmaster
• Bonluck Citystar
• Bonluck JXK6120
• Bonluck JXK6180
• Bonluck President 2
• Bonluck Senator 14

Application and Buying Notes

Before buying, confirm the part number 1277A740 and check that your original alternator matches the 24V, 155A specification. The mounting layout is just as important as the electrical rating on this unit, with a twin leg mount, 111mm inside mounting legs, 210mm mount centre to centre, and 16mm adjusting and pivot holes.

This alternator uses an internal regulator and insulated return, so it should only be selected where those details suit the vehicle or equipment setup. The shaft diameter is 30mm, the pulley section is not applicable, and rotation is bi-directional, so belt arrangement and the physical drive layout still need to be verified against the existing unit.

The listed fitment coverage includes BCI Citirider, BCI Classmaster, BCI Fleetmaster, Bonluck Citystar, Bonluck JXK6120, Bonluck JXK6180, Bonluck President 2, Bonluck Senator 14, and King Long XMQ. Model names alone are not enough on their own, so cross-check the application against the alternator dimensions and part number before fitting.

As a new alternator, this unit is intended as a direct replacement where the physical and electrical specifications align. The 18 month warranty applies to the unit supplied, but correct identification remains the buyer’s responsibility, particularly on commercial and bus applications where similar-looking alternators can have different mounts or electrical configurations.

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 1277A740 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 18 Months, Inside Mounting Legs 111mm, Power Rating (Amp) 155, Regulator Type Internal, Series AC172, Suits Unit Make Prestolite, Alternator Mount Twin Leg, New / Reman. New.

Additional published details for cross-checking include Shaft Dimension 30, Product Group 2 ALTERNATORS, Part No. 1277A740, Brand PRESTOLITE, Description Prestolite Alternator 24V 155A, Adjusting Hole Diameter 16, Pivot Hole Diameter 16, Pulley Section Not Applicable, Rotation Bi-Directional.

Prestolite Alternator 24V 155A. Part number 1277A740 should be checked first. Listed voltage is 24. Listed output rating is 155. These details form the core reference points used by parts interpreters when confirming the correct replacement.

Mount style is Twin Leg. Regulator type is Internal. Pulley configuration is Not Applicable. Those physical and electrical details should line up with the original unit before the replacement is approved for fitment.

For part number 1277A740, 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 155 should be checked carefully. Incorrect selection can affect installation time, return freight, and equipment availability.

Available application references include BCI CITIRIDER, BCI CITIRIDER 2011, BCI CITIRIDER 2012, BCI CITIRIDER 2013, BONLUCK CITYSTAR, BONLUCK CITYSTAR 2014. Even with application listings, final confirmation should still be based on the exact unit being replaced and the service requirements of the vehicle or machine.

The listed warranty is 18 Months. Warranty terms should be considered alongside correct application and part identification, as warranty does not replace fitment confirmation.

Compatibility note: Please confirm compatibility using the part number 1277A740, the 24V 155A specification, and the mounting and shaft dimensions before ordering. If the original unit differs in mount type, regulator type, rotation, or return arrangement, do not assume this alternator will suit.

FAQ

What is the part number for this Prestolite alternator?

The part number is 1277A740.

Is this alternator new or remanufactured?

It is listed as new.

What voltage and output does it have?

It is rated at 24V and 155A.

Does it use an internal regulator?

Yes. The regulator type is internal.

What are the main mounting measurements?

It has a twin leg mount, 111mm inside mounting legs, 210mm mount centre to centre, and 16mm adjusting and pivot hole diameters.

Which applications are listed for fitment?

Listed fitment includes BCI Citirider, BCI Classmaster, BCI Fleetmaster, Bonluck Citystar, Bonluck JXK6120, Bonluck JXK6180, Bonluck President 2, Bonluck Senator 14, and King Long XMQ.