The SEG Line Alternators & Starters
Every reliable vehicle depends on a high-performance charging and starting system. SEG alternators and starter motors are engineered to deliver dependable starts, stable electrical power and long-lasting performance in demanding applications — and the full range is now stocked at Leader Autoparts.
SEG charging and starting units — 14 models now stocked across the Americas
Fourteen SEG models, on the shelf and ready to ship.
Charging and starting failures rarely announce themselves. A unit that has been quietly losing output puts a truck on the shoulder, a bus off its route or a harvester out of the field at the worst possible hour — and the cost of that hour is almost never the cost of the part. That is the reasoning behind the SEG line, and behind stocking it in depth rather than ordering it in.
Leader Autoparts now carries 14 SEG models spanning both sides of the electrical system: alternators from 70A to 240A and starter motors from 2.9 to 8.0 kW, all available in 12V and 24V configurations. Every unit is built to OEM-grade specification for original-equipment fitment, and validated against commercial and industrial duty cycles rather than passenger-car ones.
Built to the specification the vehicle was designed around — not to a price point.
The range covers the alternator families technicians already ask for by name — H10LEB, HDE8, KCB1, 21SI and MG560 — alongside the 39MT, 42MT, 29MT and PLGR starter families used across heavy-duty platforms. Both lines ship from stock across the Americas, backed by nearly three decades of application experience and a technical team that answers the phone.
Seg Alternators
Supplies electrical power while keeping the battery charged — ensuring reliable operation of lighting, electronics and every other essential vehicle system, even under sustained load.
Families: H10LEB · HDE8 · KCB1 · 21SI · MG560
View alternators →Seg Starter Motors
Delivers the torque needed for quick, reliable engine starts — reducing downtime and supporting dependable daily operation across commercial and industrial fleets.
Families: 39MT · 42MT · 29MT · PLGR
View starters →
Both lines at a glance
Two product lines, one supplier, one call. Voltage, output and family coverage for the SEG units now held in stock.
| Line | Function | Voltage | Output | Families |
|---|---|---|---|---|
| Alternators | Charging | 12V & 24V | 70A – 240A | H10LEB · HDE8 · KCB1 · 21SI · MG560 |
| Starter motors | Starting | 12V & 24V | 2.9 – 8.0 kW | 39MT · 42MT · 29MT · PLGR |
Fourteen models in total. For part-number level detail — mounting, rotation, pulley and terminal configuration — see the full specification sheet linked below, or call the technical desk.
Validated for the duty cycles that punish parts
SEG units are tested against commercial and industrial workloads — long hours, heavy electrical loads, repeated cold starts and environments that are rarely clean or dry.
Trucks
Long-haul and vocational fleets running high accessory loads, day after day, between scheduled service windows.
Buses
Transit and coach duty — frequent restarts, door and HVAC loads, and routes that leave no room for a no-start.
Agriculture
Tractors, harvesters and irrigation equipment working seasonal peaks in dust, vibration and temperature extremes.
Construction
Off-road machinery where downtime stalls a whole site and access for replacement is anything but convenient.
Built to OE standards. Supplied with confidence.
Four reasons the SEG line earned shelf space at Leader Autoparts — engineering, testing, availability and the people behind the counter.
OE Heritage
Genuine OEM-grade engineering, built for original-equipment fitment and performance.
Heavy-Duty Tested
Validated for commercial and industrial duty cycles — trucks, buses, agriculture and construction.
Dependable Supply
Stocked inventory and consistent availability across the Americas — 24+ countries served.
Expert Support
Nearly three decades of application know-how, with responsive technical assistance.
Five things to confirm before you order
Most charging and starting returns come down to a detail checked too late. Have these five in front of you — or the old unit in hand — and the replacement goes in first time.
- 1System voltage
12V or 24V. Read it from the unit's own label rather than assuming from the platform — mixed fleets and retrofits are where this goes wrong.
- 2Output rating
Amperage for alternators, kilowatts for starters. Match or exceed the original; added electronics, lighting bars and auxiliary equipment push demand above the factory figure.
- 3Mounting and clocking
Bracket type, bolt centres, spigot diameter and the orientation of the terminals relative to the mount. A correct unit in the wrong clock position still will not fit.
- 4Drive detail
Alternators: pulley type, groove count and rotation. Starters: drive tooth count, module and pinion offset against the ring gear.
- 5Regulation and connections
Internal or external regulation, sense and ignition terminals, and any control interface the vehicle expects to see from the charging system.
Before you specify
The five things the technical desk gets asked most about the SEG line.
What does "OEM grade" mean here?+
SEG units are engineered to original-equipment specification and fitment rather than to a generic aftermarket equivalent — the same design intent, materials and output behaviour the vehicle was built around.
Are these units held in stock, or built to order?+
Stocked. All 14 SEG models are held in inventory and supplied across the Americas, with distribution reaching 24+ countries. Availability by part number can be confirmed by the sales desk.
Can you help me cross-reference an existing part number?+
Yes. Send the number from the unit's label, or the vehicle and engine details, and the technical team will identify the SEG equivalent and flag any differences in mounting, rotation or terminal layout.
Which families are covered?+
Alternators: H10LEB, HDE8, KCB1, 21SI and MG560. Starters: 39MT, 42MT, 29MT and PLGR. Part-number level coverage within each family is listed in the specification sheet.
How do I get pricing and warranty terms?+
Contact the sales team for current pricing, terms and warranty details on the SEG line — call +1 (305) 470-1800 or use the contact form.
Full specifications & applications
Browse the complete SEG range — part numbers, families, voltage and output.
View all detailsQuestions? Call +1 (305) 470-1800