Feed Mixer Gearbox EP-Series — Planetary Gear Drives for Vertical TMR Mixing

EP-Series Planetary Feed Mixer Gearbox

Vertical TMR (Total Mixed Ration) mixers demand a gearbox that can convert high-speed, low-torque tractor PTO output into the slow, high-torque rotation needed to drive heavy auger screws through dense feed materials. The EP-Series feed mixer gearbox line uses planetary gear trains to achieve reduction ratios from 13.38:1 to 28.27:1, producing output torques between 12,000 and 18,020 Nm — enough to turn single or twin augers loaded with hay, silage, grain, and mineral supplements at the controlled speeds required for uniform ration blending.

Sixteen configurations (E1 through E16) span power ratings from 32 kW to 76 kW, accepting both 540 RPM and 1000 RPM PTO inputs depending on the model. Unit weights range from 256 kg to 330 kg, corresponding to different torque capacities and housing sizes. Each unit ships as a complete drop-in pto gearbox assembly compatible with most vertical mixer brands used on Korean and Asian dairy and livestock operations.

Planetary gear architecture is the defining technical choice in this product line. Unlike single-stage bevel or helical reduction, a planetary set distributes load across three or four planet gears simultaneously — resulting in higher torque density per kilogram of gearbox weight. This matters on feed mixers because the gearbox mounts directly on top of the mixing tub, and every kilogram of drivetrain weight above the center of gravity affects trailer stability on uneven farm roads.

Complete Model Range — Technical Data

The table below lists all 16 EP-Series configurations. Match your tractor PTO speed (540 or 1000 RPM), required power throughput, and target output torque to identify the correct model. All torque values represent continuous-duty ratings, not peak.

Bold rows indicate highest-torque models (18,020 Nm). E7/E16 are the top 540 RPM configurations; E9/E15 are the top 1000 RPM configurations.

Why Planetary Drives Dominate Feed Mixer Applications

Matching the EP-Series to Your Mixing Operation

Small Dairy Farms (30–80 Head)

Korean dairy operations in Chungcheong and Gyeonggi provinces with herds under 80 head typically use single-auger vertical TMR mixers in the 6–10 m³ range. The E6 or E14 (21.10:1 ratio, 12,000 Nm torque at 32 kW) provides sufficient auger drive force while keeping tractor PTO demand within the 40–50 HP range common on these smaller farms. The 256 kg unit weight keeps the mixer's center of gravity manageable on narrow farm roads.

Mid-Size Livestock Operations (80–300 Head)

Farms feeding 80 to 300 animals need 12–18 m³ twin-auger mixers. The E1 (14.60:1 ratio, 16,000 Nm) or E4 (16.13:1 ratio, 15,700 Nm) handle the higher auger loads and denser feed mixes common at this scale. At 55–62 kW rated power, these models pair with the 80–100 HP tractors that mid-size Korean operations typically run.

Large-Scale TMR Centers and Contract Feeders

Commercial TMR centers processing feed for 500+ head on large farms in Jeju-do and Gangwon-do need the highest torque models. The E7 (13.40:1 ratio, 18,020 Nm at 76 kW) and E16 (13.38:1 ratio, 18,020 Nm at 76 kW) drive 20–30 m³ mixers loaded with heavy wet silage, whole cotton seed, and mineral premixes. For operations with 1000 RPM PTO tractors, the E9 and E15 deliver the same 18,020 Nm at 1000 RPM input.

Five-Step Selection Guide for Feed Mixer Gearboxes

Choosing the wrong pto gearbox for a feed mixer gearbox application results in either premature gear failure (undersized) or unnecessary weight and cost (oversized). Follow this sequence to identify the right EP-Series model:

1. Confirm tractor PTO speed. Check whether your tractor delivers 540 RPM or 1000 RPM at rated engine speed. Models E3, E8, E9, and E15 are the only four 1000 RPM options — all others are 540 RPM. Running a 540-spec gearbox on a 1000 RPM PTO will over-speed the planetary set and void the warranty.
2. Calculate required output torque. Multiply your mixer's specified auger torque demand (in Nm) by a 1.25 safety factor to account for peak loads from compacted feed pockets and startup inertia. If your mixer manual lists 13,000 Nm auger torque, target a gearbox rated for at least 16,250 Nm continuous.
3. Verify power throughput. Confirm that your tractor can deliver the kW listed for your target model. The E7 requires 76 kW (approximately 102 HP) at the PTO — running it on a 70 HP tractor will stall under full load.
4. Match the reduction ratio to desired auger speed. Higher ratios (25–28:1) produce slower auger rotation — suitable for dense, heavy mixes that need long residence time. Lower ratios (13–16:1) deliver faster auger speed for lighter dry-hay mixes that benefit from more aggressive tumbling action.
5. Check weight constraints. If your mixer trailer has a maximum top-load rating, compare the gearbox weight (256–330 kg) against that limit. The difference between a 256 kg and 330 kg unit can matter on single-axle trailers operating on sloped terrain.

Need help matching a specific mixer brand and model to the correct EP-Series gearbox? Browse our full pto gearbox catalog or contact our engineering team with your mixer's make, model, tub volume, and tractor PTO specification for a confirmed selection recommendation.

Planetary vs. Helical Gearboxes for Feed Mixing Drives

Feed mixer builders choose between two primary gear architectures. The table below compares their characteristics for this specific application — not as a general gear technology overview, but focused on the factors that matter when driving a vertical auger through 10+ tons of mixed rations.

For feed mixer duty — where high torque, compact packaging, coaxial alignment, and shock load tolerance matter more than absolute efficiency and noise — the planetary configuration wins on the criteria that affect mixer performance and trailer handling. Helical drives have their place in stationary industrial mixers where weight is irrelevant and noise control is the priority.

Note: Efficiency figures represent clean-oil, room-temperature conditions. Field efficiency varies with oil viscosity, ambient temperature, and load profile.

Relevant Industry Standards for PTO-Driven Mixer Gearboxes

• ☑ ISO 500 — Agricultural Tractors, PTO — Defines 540 RPM and 1000 RPM PTO speed categories, spline dimensions, direction of rotation, and guard zone requirements. All EP-Series models conform to ISO 500 Type 1 (540 RPM) or Type 3 (1000 RPM) input specifications. Selecting a gearbox that matches your tractor's ISO 500 PTO type prevents spline damage from speed or dimensional mismatch.
• ☑ ISO 5673 — PTO Drive Shaft Dimensions — Specifies the physical dimensions of the drive shaft connecting tractor PTO to implement gearbox, including spline profiles, shaft diameters, and length tolerances. The EP-Series input spline conforms to ISO 5673 to accept standard pto drive gearbox shaft assemblies without adapters — a critical compatibility factor for any agricultural gearbox serving Korean dairy operations.
• ☑ SAE J744 — PTO Speed and Power Test Code — Establishes the testing protocol for measuring PTO power output on agricultural tractors. The power ratings (kW) listed in our specification table are measured per SAE J744 procedures, giving you a directly comparable figure against your tractor's published PTO rating.
• ☑ ISO 9001:2015 — Quality Management — Our manufacturing facility holds ISO 9001 certification, with documented processes for gear grinding tolerance, heat treatment parameters, and final assembly inspection. Each EP-Series unit undergoes a loaded run-in test before shipping.

Understanding these standards helps when comparing agricultural gearbox specifications across different suppliers — if a competitor does not state which test protocol their power rating follows, the numbers may not be directly comparable to ours.

Field Report: 2,400-Hour Dairy Operation in Chungcheongnam-do

The previous gearbox for feed mixers on this machine — a European-sourced helical unit — failed at approximately 1,800 hours when the output bearing collapsed under load. Downtime for the replacement import took 17 days, during which the farm hand-mixed rations with a front loader at significant labor cost.

After installing this agricultural gearbox in March 2023, the farm has logged over 2,400 operating hours through January 2025. Oil analysis at 500-hour intervals shows iron particle counts within normal wear range, and the output bearing preload has remained within factory specification. The 14.60:1 ratio produces an auger speed of approximately 37 RPM at 540 RPM PTO input — well-matched to the slow tumbling action this mixer design requires for uniform TMR distribution.

The 256 kg unit weight (versus 380 kg for the previous helical unit) dropped the mixer's top-heavy load by 124 kg, which the farm manager reports as a noticeable improvement in trailer handling on the 15% grade slopes between the feed storage barn and the cow shed.

Complete Your Mixer Drive System

The planetary gearbox connects to your tractor through a pto shaft that must be rated for the full torque and power of the selected EP-Series model. For the E7 at 76 kW, specify a wide-angle PTO shaft with a continuous torque rating above 18,000 Nm and adequate collapsed length for the distance between your tractor PTO and the mixer gearbox input. Constant-velocity joints are recommended for mixers that operate at steep PTO angles during loading and unloading.

For mixed-use farms that also operate rotary cutters, tillers, or spreaders, our full agricultural gearbox catalog includes bevel, helical, and worm-gear units alongside this planetary series — all available as pto gearbox for sale with factory-direct pricing and Korean domestic delivery.

Frequently Asked Questions

Can I use a 540 RPM EP-Series model on a 1000 RPM PTO?
No. Running a 540-rated model at 1000 RPM over-speeds the planetary set, generates excessive heat, and will cause premature ring gear failure. Use only the E3, E8, E9, or E15 on 1000 RPM tractors.

What oil type and change interval does the EP-Series require?
Use ISO VG 220 or VG 320 synthetic gear oil for planetary sets operating under sustained load. First drain at 100 hours to flush break-in particles; subsequent changes every 1,000 hours or annually. Check oil level weekly — planetary housings have tight internal clearances that are sensitive to low-oil conditions.

How do I know if my mixer needs a 13:1 or a 25:1 ratio?
Low ratios (13–16:1) produce faster auger speeds for light dry-hay mixes. High ratios (21–28:1) slow the auger for dense wet silage mixes that need longer blending time per revolution. Your mixer manufacturer typically specifies the recommended auger RPM range — divide your PTO speed by that target RPM to find the ratio you need.

Do these gearboxes fit Kuhn, Trioliet, or Keenan vertical mixers?
The EP-Series uses standard mounting patterns. Adapter plates are available for specific mixer brands. Contact our engineering team with your mixer make and model for a compatibility check and adapter recommendation.

What causes a planetary gearbox to fail in feed mixer service?
Three primary causes in order of frequency: lubricant starvation (missed oil checks), contamination (failed input seal allowing feed dust into the housing), and sustained overload (running a mixer too full or with compacted material). All three are preventable with the maintenance practices above.

Is the E8 (330 kg) significantly stronger than the E3 (290 kg) even though both use 1000 RPM input?
The E8 delivers 16,500 Nm versus the E3 at 16,000 Nm — a modest torque increase. The weight difference comes from a larger housing and heavier-duty bearings that extend service life under sustained high-load duty. Choose the E8 for operations running two or more batches daily at near-maximum load.

Customer Feedback from the Field

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Han Dong-wook, Dairy Farm Owner — Hongseong, Chungcheongnam-do, February 2025

"Switched from a European helical unit to the E1 after the original failed at 1,800 hours. The EP unit has now passed 2,400 hours with no issues. Oil analysis comes back clean every time. The lighter weight made a noticeable difference in trailer handling on our sloped farm roads."

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Seo Eun-ji, Feed Operations Manager — Pocheon, Gyeonggi-do, December 2024

"We run the E7 on a 20 m³ twin-auger mixer. The 18,020 Nm output handles full-load batches of wet corn silage without the PTO stalling. Previous gearbox needed 15 minutes to start mixing on cold winter mornings — this one turns over immediately."

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Jang Hyun-woo, Agricultural Contractor — Seosan, Chungcheongnam-do, October 2024

"Operate three TMR mixers for contract feeding across five dairy farms. Standardized on the E4 for all three machines — simplifies spare parts inventory for this pto gearbox range. 1,600 hours on the oldest unit with normal oil consumption. The 16.13:1 ratio gives us 33 RPM auger speed, right in the sweet spot for our mix recipes."

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Noh Su-bin, Beef Cattle Farmer — Hoengseong, Gangwon-do, August 2024

"Small operation, 60 head. Went with the E6 based on Ever-Power's recommendation — lower torque model since our feed is mostly dry hay and pellets. Runs quiet and smooth on our 45 HP TYM tractor. Delivery to Gangwon-do took 4 days."

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Kwon Ji-young, Livestock Equipment Dealer — Iksan, Jeollabuk-do, June 2024

"Stocking the EP-Series as a replacement line for customers whose imported mixer gearboxes fail out of warranty. The range of 16 models means I can match almost any mixer specification. Margins are better than imports, and I have not had a single warranty claim in the first year."