24SI 24V 70A alternator 8600017 4936879 24SI 8600407 3972735 4993343 2874863
Applicable models:Cummins LG925/R225-7
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Reference part number:8600017 4936879 24SI 8600407 3972735 4993343 2874863 MDA3946 UD15124A A1052S 8709N CAL60615ES CAL606150S,CAL60615RS 24SI 6089167.6162529 116317 K9002605 8600407，8600504,8700019,5282841.C3972735 2874863.3972735.4003446.4936879.4993343 8600017,8600020,8600154,8600360,CU5282841 4020872 82827042 71440388,71440473.71440537 8600020, 8600154,ALD0019RB,1-3122-00DR ALD0019GB,ALD0019LK,ALD0019MA.ALD0019NB,ALD0019NW ALD0019SK ,ALD0019UW,ALD1019UW,ALD8019LP
Product Attributes
| Rated output : | 28V 70A |
| Pulley : | 8PK |
| Size : | 24*18*17 cm single unit inner box |
| Weight : | net weight：8.0KG gross weight：8.5KG |
| Packaging : | Neutral kraft paper packaging |
| Spot/Pre sale : | Spot goods |
| Warranty : | 1 year |
| Product number : |
Product Details
| Type : | AIternator |
| Specification : | 28V 70A |
| Pulley : | 8PK |
| Brand : | nuojin |
| Number : | 8600017 4936879 24SI |
| Quality : | Remanufacture |
| Delivery time : | 10DAY |
Installation Method for Cummins LG925/R225‑7 28V Alternator
The installation of the Cummins LG925/R225‑7 28V alternator must comply with Cummins original factory specifications. The core principles include power disconnection for safety, precise coaxial alignment, torque‑specified fastening, standard wiring, and commissioning. This procedure is suitable for construction machinery applications such as excavators, and the structured installation method below can be directly used in technical manuals.
I. Pre‑Installation Preparation (Mandatory for Safety and Compliance)
Safety Protection and Power Disconnection
Disconnect the negative battery terminal (for 28V systems, disconnect the negative terminal first to prevent short circuits), and wait 5–10 minutes to discharge residual electrical charge. Live operation is strictly prohibited throughout the process.
Wear insulated gloves and safety goggles. Clear flammable materials and oil contamination from the installation area, and ensure a well‑ventilated and dry working environment.
Tools and Auxiliary Materials
| Category | List |
|---|---|
| Basic Tools | 10/12/14/17mm socket wrenches, torque wrench, belt tensioner, spirit level, rubber mallet |
| Special Tools | Coaxiality inspection tool, bearing installation tool, brush preloading tool |
| Auxiliary Materials | 28V‑rated insulating tape, high‑temperature resistant grease, thread locker (Loctite 242), anti‑vibration pads |
Component Inspection
Verify that the alternator model LG925/R225‑7 matches the engine. Check that the stator, rotor, and rectifier bridge are free of damage, and that the terminal posts are free of oxidation and deformation.
Inspect the pulley, bearings, carbon brushes, and one‑way clutch to ensure no jamming, abnormal noise, or excessive wear.
Check the mounting surface, locating pins, and bolt holes. Clean oil contamination, rust, and burrs, and replace aged seals and gaskets.
II. Core Installation Steps (Perform in Sequence; Coaxiality, Torque and Wiring Are Critical)
Positioning and Preliminary Fastening
Clean the engine mounting surface and alternator flange, and install a new gasket to ensure gap‑free fitting.
Install 2 locating pins diagonally. Align the alternator flange with the engine flywheel housing, ensuring the drive shaft is coaxial with the crankshaft. Thread 2–3 bolts in manually for preliminary fastening (do not fully tighten; leave clearance for coaxiality adjustment).
Level using a spirit level and install anti‑vibration pads to prevent resonance damage to bearings and windings.
Coaxiality and Meshing Clearance Inspection (Critical for Failure Prevention)
Use a dial indicator to measure the coaxiality between the alternator shaft and crankshaft. Radial runout ≤ 0.1 mm, and axial clearance 0.2–0.5 mm.
Rotate the pulley manually to check the gear meshing depth, and ensure no jamming or eccentric wear. If abnormalities are found, correct by adjusting gasket thickness or locating pin position.
Bolt Fastening (Torque + Sequence to Prevent Loosening / Deformation)
Apply a small amount of thread locker to the bolt threads. Tighten the bolts in diagonal cross sequence in 2–3 stages to the specified torque values:
Main mounting bolts: 35–45 N·m
Pulley retaining nut: 25–30 N·m
Terminal post nuts: 10–15 N·m
Single‑step full tightening is strictly prohibited to avoid housing deformation or bolt fracture.
Mechanical Drive Installation
Install the matched pulley, ensuring the groove profile is consistent with the crankshaft pulley. Maintain proper belt tension (deflection of 10–15 mm when pressing the middle of the belt is recommended).
Install the belt tensioner and adjust to the specified tension to avoid slipping or excessive tightness that damages bearings.
Electrical Wiring (Prevent Reverse Connection / Short Circuit)
Main terminal B+ (thick post): Connect the thick positive cable from the 28V battery. Polish oxidation from the terminal post, install an insulating boot, and tighten to 10–15 N·m.
Field terminal F: Connect the field wire from the regulator, ensuring the connector is fully locked and free of loose connection.
Ground wire: Connect to a clean, dedicated grounding point on the engine block, ensuring conductance resistance ≤ 0.1 Ω.
Route wiring harnesses away from high‑temperature areas (exhaust pipe, turbocharger) and moving components (belts, fan), and secure with cable ties to prevent abrasion.
Restore power: reconnect the positive battery terminal first, then the negative terminal to avoid arc damage.
Commissioning and Trial Operation
Run the engine at idle speed for 3–5 minutes. Measure the output voltage, which should be 27–29 V for a 28V system. Confirm no abnormal noise, odor, or overheating.
Load test: gradually apply load to the rated capacity. The voltage must remain stable at 27–29 V, with no fluctuation or fault alarms.
Interval between consecutive starts ≥ 1 minute; single start duration ≤ 5 seconds to prevent winding overheating.
Post‑Installation Recheck (Closed‑Loop Hazard Prevention)
After shutdown, recheck the tightness of bolts and terminal posts to ensure no looseness. Inspect the mounting surface for no leakage.
Clean the engine compartment, organize tools and old parts, and record installation parameters and test data.
Special Installation Precautions for Cummins LG925/R225‑7 28V Alternator
The following special installation precautions are organized into five categories: electrical safety, mechanical installation, electrical wiring, commissioning and operation, and maintenance traceability. All content complies with original Cummins specifications and is tailored for construction machinery, including the Hyundai R225‑7 excavator. This text can be directly incorporated into service manuals and work instructions.
I. Electrical Safety (Highest Priority – Extremely High Short‑Circuit Risk in 28V Systems)
Strict Power‑Disconnection Procedure
During installation, removal, and wiring, the negative battery terminal must be disconnected first, and a waiting period of 5–10 minutes must be observed to discharge residual electrical charge. Live plugging/unplugging, live fastening, and live measurement are strictly prohibited.The short‑circuit current of a 28V system is significantly higher than that of a 12V system, which can easily produce intense arcing, terminal post erosion, wiring harness burnout, and even fire.
Absolute Prohibition of Polarity Reversal
The Cummins LG925/R225‑7 alternator is equipped with an internal rectifier bridge and excitation regulator. Reversing the B+ positive polarity will instantly destroy the rectifier module, burn out the excitation coil, and damage the entire machine controller, and such damage is not covered under warranty.Before wiring, verify the wiring harness labels and alternator terminal markings, and confirm polarity using a multimeter.
Terminal Insulation and Short‑Circuit Prevention
The B+ main power terminal carries high potential. After tightening, it must be fitted with the original factory insulating boot; exposed terminals are strictly prohibited.All wiring harnesses must be routed away from high‑temperature components such as the exhaust pipe and turbocharger, as well as moving parts including the fan, belts, and linkages. Secure harnesses with flame‑retardant cable ties to prevent abrasion, exposed conductors, and short circuits.Do not use metal tools such as wrenches or screwdrivers to contact both the B+ terminal and the engine block simultaneously, to avoid instantaneous short circuits.
Mandatory Requirements for Reliable Grounding
References：
The following authoritative sources are categorized into original factory core documents and general industry standards, all traceable and verifiable, suitable for technical manual compilation and compliant operation.
I. Core Original Factory Authoritative Sources (Official Technical Documents from Cummins and Hyundai Excavator)
Cummins Original Service Manual
Applicable models: Cummins LG925/R225‑7 28V alternator (matched for Hyundai R225‑7 excavator), corresponding to the engine electrical system chapter (e.g., Charging System – Generator Installation).Core content: Power disconnection procedure (negative terminal first + 5–10 minutes residual discharge), diagonal cross tightening of bolts, torque specifications (main bolts: 35–45 N·m, etc.), insulation of the B+ terminal, prohibition of live operation, and other safety provisions.Access path: After-sales section of the official Cummins website, authorized dealer database, and Cummins INSITE global service system. Search for the corresponding chapter by entering the alternator model or serial number.
Hyundai R225‑7 Excavator Original Service Manual
Chapter location: Starting & Charging System under the engine system section. It specifies alternator installation requirements for 2.0L β and 2.7L δ engines, including model-specific specifications such as coaxiality, belt tension, and installation of anti-vibration pads.Access path: Authorized Hyundai dealers and the Hyundai Global Service Information (HGSI) system. Search by model code such as B02 (2.7L δ engine).
Original Factory Parts Installation Instructions for Cummins LG925/R225‑7 Alternator
Issuing body: Cummins Inc. Contents include model matching tables, terminal definitions, seal replacement requirements, application specifications for thread locker and high-temperature grease, with emphasis on reverse‑connection protection for 28V systems and the grounding continuity resistance standard (≤ 0.1 Ω).Access path: Documentation supplied with Cummins parts packaging, and parts departments of authorized dealers.
Cummins Engine Operation Manual
Core provisions: Single start duration ≤ 5 seconds, interval between consecutive starts ≥ 60 seconds, 3–5 minutes of no-load idle testing, and other commissioning specifications. These clauses are commonly found in the operation specification sections of operator manuals and service manuals.
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