EP01-672 Baler Speed Increaser Gearbox – 50HP, 1.92:1 and 1.47:1 Dual Ratio

EP01-672 · 50HP · 1.92:1 & 1.47:1 · 18.5kg · 101×101mm

101×101mm square cross-section · 155.5mm height · Φ85.75mm output

Output Torque is Lower Than Input

In a speed increaser, output torque = input torque ÷ ratio. At 1.92:1, the output torque is approximately 52% of the input torque. At 1.47:1, approximately 68%. This is why speed increasers are appropriate for mechanisms with low torque requirements (wrap rollers, belt drives, secondary conveyors) — not for main bale chamber drives where high torque at low speed is needed. Specifying the EP01-672 for a main bale chamber that requires high output torque would result in the mechanism stalling under load because the torque available at the output is insufficient.

Power Rating Remains 50HP

Power (kW) = torque × angular velocity. In a speed increaser, lower output torque and higher output speed mean the power capacity remains constant through the gearbox (minus a small efficiency loss). The EP01-672's 50HP rating applies at the output shaft at both ratio configurations — the available power at the mechanism is 50HP regardless of which ratio is selected. The trade-off is torque-for-speed: more speed means less torque at the same power level.

Why M6.5 at the Higher Ratio

At 1.92:1, the driven gear (12 teeth) rotates at 1,037RPM — each tooth mesh contact event occurs at 1,037 × 12 = 12,444 tooth contact events per minute on the driven gear. The high contact frequency combined with the 50HP input load (which produces the input-side tooth bending stress) requires M6.5 to maintain the tooth root cross-section and surface hardness within the fatigue safety margin. The 1.47:1 config's driven gear (15 teeth at 794RPM) has a lower contact frequency (794 × 15 = 11,910 per minute) and benefits from a slightly lower module M5.65, which is still custom-calculated for this exact combination.

Oil Temperature at High Speed

Speed increasers generate more heat per unit time than speed reducers at the same power level, because the higher gear mesh velocity creates more friction energy per second within the oil film. The EP01-672's compact 18.5kg housing has a relatively small oil sump volume. In sustained operation at high ambient temperatures — common in summer baling in Korea and Southeast Asian climates — check housing surface temperature at 100 hours: if above 75°C, reduce oil change interval to 150 hours and consider switching to a higher-viscosity SAE 140 or 80W-140 gear oil for better film strength at elevated temperature.

Square GGG50 Housing

The 101×101mm square cross-section provides equal wall thickness on all four sides of the housing — a symmetric geometry that distributes the torque reaction loads from the bevel gear mesh equally around the housing perimeter. GGG50 nodular cast iron maintains dimensional stability under the torsional and bending moments of 50HP speed-increase operation, where the housing must resist both the gear mesh reaction torque and the gyroscopic moments from the high-speed output shaft bearing loads.

Non-Standard Module Gears

M6.5 and M5.65 are non-standard module values — purpose-calculated for their specific ratio and load conditions within the 101mm housing constraint, identical in design philosophy to the M4.23 of the EP-68° and M4.35 of the EP-9.311. Both gear sets are carburised to 0.8–1.2mm case depth and quench-hardened to HRC 58–62, the same specification used across the EP series. The driven gear (smaller tooth count, higher RPM) receives particular attention in the hardening process because the higher contact frequency concentrates cumulative contact fatigue on fewer tooth pairs than in a speed-reducing arrangement.

High-Speed Output Bearing

The output shaft bearing at 794–1,037RPM operates at significantly higher speed than output shaft bearings in EP speed-reducing gearboxes. The EP01-672 uses angular contact ball bearings at the output position — the correct bearing type for the combined radial and axial loads at high output speed, where tapered roller bearings would generate excessive heat through rolling friction at these velocities. Bearing pre-load is verified during the load test to confirm that neither pre-load deficiency (allowing shaft wobble) nor pre-load excess (causing overheating) is present at the ordered configuration's output speed.

Load Test at Output Speed

Every EP01-672 is tested at full 50HP rated load at the ordered output speed — 1,037RPM for Config A, 794RPM for Config B. For a speed-increasing unit, this means the test bench must absorb the full output power at the higher shaft speed, not at a convenient lower speed. The test confirms bearing temperature at the actual operating speed (critical for the high-speed output bearing), gear noise character at the output frequency, and oil seal integrity under the higher centrifugal forces at output speed.

Non-standard module gear production — same CNC hobbing as EP-40002 series

Cho Tae-yang Round Baler OEM Manufacturer · Gyeongju, North Gyeongsang, South Korea · 2024

We build mid-format round balers for the Korean forage and straw market. Our net-wrap system requires approximately 1,000RPM input to the feed roller — exactly what the EP01-672 Config A provides at our machine's 540RPM PTO setting. Before we found Korea Ever-Power's EP01-672, we were sourcing this speed-increaser from a European supplier with 6-week lead times, which made running replacements in stock impractical. Korea Ever-Power delivers in 4 days. We've now been using the EP01-672 in production for 11 months across 65 machines shipped. No net-wrap drive failures related to the gearbox. Oil temperatures at the 100-hour check are within the normal range. Consolidated supply with the EP-40002 for our main chamber also simplified our purchasing.

Yamada Koji Agricultural Machinery Design Engineer · Saitama Prefecture, Japan · 2024

I design variable-chamber round balers for a Japanese manufacturer targeting the Hokkaido forage market. Our belt tensioner design requires a 790RPM driven roll input — the EP01-672 Config B at 794RPM is close enough that we confirmed fit with a tachometer measurement before adopting it. The compact 101×101mm housing fits within our frame design envelope without modification. We ran prototype testing for 80 hours before production approval; belt tension consistency was within our target spec throughout. Korea Ever-Power provided a dimensional drawing on request promptly, which was essential for our integration design work.

Park Sang-woo Agricultural Machinery Workshop · Yeongju, North Gyeongsang, South Korea · 2024

I service balers for straw and forage producers in the Yeongju area. The most common call I get is net-wrap problems — either the net doesn't deploy evenly or the mechanism jams. In my experience, 60% of net-wrap problems trace back to the speed-increase gearbox being worn or wrongly specified. I now stock one EP01-672 Config A unit. The last repair I used it on was a European-brand baler whose original speed increaser had worn to the point where output RPM was 15% below design — causing uneven net deployment at the bale shoulder. The EP01-672 replacement restored correct RPM and the net pattern was correct from the first bale. Four-day delivery from Korea Ever-Power made the repair turnaround same week.

Nguyen Thanh Phong Agricultural Machinery Dealer · Ho Chi Minh City, Vietnam · early 2025

I supply baler parts to rice straw baling contractors in the south. My customers run mid-format round balers and the speed-increase gearbox is the component that fails most often in our hot, dusty environment — oil temperature runs high and the seals degrade faster here. I ordered three EP01-672 Config A units as stock replacements. All three delivered to Ho Chi Minh City in 7 days. The first unit was fitted on a customer's baler with a worn net-wrap gearbox; the temperature profile we measured was higher than expected due to the hot season, so I recommended the customer switch to 80W-140 oil at the 100-hour mark as the Korea Ever-Power documentation suggested. That resolved the temperature concern and the net-wrap has run correctly since. Good product, honest documentation.

Can the EP01-672 replace the main bale chamber gearbox on my round baler?

No. The EP01-672 is a speed increaser — its output shaft turns faster than the input, not slower. Main bale chamber drives require speed reduction (output slower than input, with high torque) provided by gearboxes like the EP-40002 or EP-BGB8. The EP01-672's output torque is lower than its input torque (approximately 52% at 1.92:1), which is insufficient to drive a bale chamber against the compression resistance of bale formation. If you need a main chamber drive replacement, see the EP-40002 (85HP) or EP-BGB8 (30HP) product pages.

My net-wrap mechanism needs approximately 850RPM — which configuration fits best?

Config B (1.47:1, ≈794RPM) is closer at 7% below your requirement than Config A (1.92:1, ≈1,037RPM) which is 22% above. At 850RPM design speed, Config B is the better choice — a 7% under-speed in the net-wrap will have minimal effect on net deployment pattern (net will wrap slightly more loosely than design, easily corrected by adjusting the net tension brake). A 22% over-speed from Config A would be more likely to cause net tearing or tension faults. Contact Korea Ever-Power with your exact mechanism speed requirement and the original gearbox ratio if known — we can confirm the correct configuration.

What is the oil specification and how does the smaller sump affect maintenance?

SAE 90 GL-4 gear oil, approximately 150–200ml fill volume. The compact 101×101mm housing has a correspondingly small oil sump compared to the EP-40002 or EP-75. This means the oil thermal buffer capacity is lower — the oil reaches operating temperature faster and degrades faster per operating hour at high ambient temperatures. Standard interval: first change at 50 hours, subsequent changes every 200 hours. In sustained operation above 35°C ambient, check housing surface temperature at 100 hours; if above 75°C, reduce interval to 150 hours and consider SAE 140 or 80W-140 oil for better film strength at elevated temperature. Do not run dry — the EP01-672 ships without oil; fill before first operation.

Is the optic axis output compatible with my existing mechanism coupling?

The optic axis output is a plain round shaft of Φ85.75mm stub diameter. It connects to the mechanism via a standard bore-and-key coupling — a split clamp hub, a keyed coupling, or a plain bore flange, all of which are stock items in baler component supply catalogues. Verify that your coupling's bore diameter matches Φ85.75mm before ordering. If your existing mechanism used a different output type (spline, taper, or different optic axis diameter), contact Korea Ever-Power with the original shaft dimensions and we will confirm compatibility or advise on coupling adaptation options.

What warranty and shipping options apply?

12-month warranty against manufacturing defects — housing integrity, gear tooth failure within 50HP rated load, bearing failure not caused by oil neglect, and seal defects present at delivery. Not covered: dry running before initial oil fill, operation above 50HP rated input, or output-shaft coupling mismatch causing shaft overload. Shipping: DHL or FedEx, 3–5 days to Korea and Japan, 5–7 days to SEA for 1–10 units. Sea freight for larger orders (10–18 days). Full export documentation including Certificate of Origin for RCEP and ASEAN preferential tariff applications on every shipment.