Product Overview — EP-S77 Helical-Worm Gear Reducer
For continuous-duty industrial production — plastics processing, grain handling, ceramic production, and wastewater treatment — a gear reducer must sustain torque, resist thermal degradation, and require minimal maintenance across extended service intervals. The EP-S77 helical-worm gear reducer is designed for this profile, with up to 1,350 N·m output torque from 0.18–7.5 kW across ratios of 8.74–196.11 and an overall efficiency of 72–80% that keeps operating heat well within housing limits at sustained full load.
The EP-S77 worm wheel uses a high-tin-content phosphor-bronze alloy selected for its combination of load capacity and low worm sliding friction. The hardened, profile-ground worm shaft — with surface roughness Ra ≤ 0.4 µm — maintains lubrication film continuity even at low sliding speeds, preventing the adhesive wear that prematurely ages conventional worm-wheel sets in slow-cycle applications.
The housing is heavily ribbed on the worm-gear side, where heat generation is highest, maximising natural-convection area and reducing steady-state oil temperature. Where ambient conditions are challenging, an external oil-cooler manifold can be fitted without removing the gearbox from its mounting. Browse the complete S-series and other helical gear families on the Ever Power product homepage.
Technical Specifications — EP-S77
| Parameter | Specification |
|---|---|
| Gear Type | Helical pre-stage + worm gear set (right-angle output) |
| Number of Stages | 2 (1 helical + 1 worm) |
| Motor Power Range | 0.18–7.5 kW |
| Max Output Torque | 1,350 N·m |
| Gear Ratio Range | 8.74–196.11 |
| Output Speed Range | 7–161 rpm |
| Approximate Unit Weight | 38–58 kg |
| Max Output Radial Load | 12,500 N |
| Overall Efficiency | 75–82% (vs 55–65% for equivalent single-stage worm) |
| Lubrication | Oil bath; ISO VG 220 synthetic-blend worm gear oil (factory fill) |
| Housing Material | Close-grained cast iron (HT250) |
| Worm Shaft Material | 20CrMnTi alloy steel, case-hardened HRC 58–62, profile ground Ra ≤ 0.4 µm |
| Worm Wheel Material | Centrifugally cast phosphor-bronze (ZCuSn10P1) |
| Helical Stage Material | 20CrMnTi alloy steel, case-hardened, precision ground DIN 6 |
| Protection Rating | IP55 standard; IP65 optional |
| Ambient Temperature | −25 °C to +40 °C (standard lubricant) |
| Noise Level | ≤ 68 dB(A) at rated load (1 m, free-field) |
| Standards Compliance | ISO 14521 worm gear rating; ISO 281 bearing life; CE Machinery Directive |
Structural Types & Mounting Configurations — S77 Series
The S77 series is produced in five structural types plus an input-shaft-only SA-SZ variant. All share the same internal helical-worm gear train and achieve identical output torque and efficiency ratings. The structural type determines the mounting method and driven-machine interface.
| Type Code | Description |
|---|---|
| S77 | foot-mounted, solid output shaft |
| SF77 | B5 flange-mounted, solid output shaft |
| SA77 | shaft-mounted, hollow output bore |
| SAF77 | B5 flange + hollow output bore |
| SAT77 | torque-arm, hollow output bore |
SF and SAF Mounting Positions
Flange-mounted SF77 and SAF77 variants support all six standard mounting positions. Oil fill level and breather plug position must be adjusted per mounting position — refer to the position-specific lubrication table in the installation manual.
SA and SAT Torque-Arm Mounting Positions
The SA77 shaft-mounted and SAT77 torque-arm variants mount directly onto the driven shaft, reacting torque through the torque arm rather than a baseplate. This eliminates shaft-to-shaft coupling alignment and is particularly suited to conveyor head drives and drum agitators.
Key Advantages of the EP-S77 Helical-Worm Reducer
The helical input stage of the EP-S77 achieves ≥98% per-stage efficiency, contributing directly to the 75–82% overall efficiency of the complete unit — 15–25 percentage points above conventional single-stage worm reducers. In continuous-duty applications this margin translates to measurable energy cost reduction and lower operating heat, reducing cooling requirements and extending lubricant life.
The S-series right-angle configuration delivers 1,350 N·m from a housing sized for 0.18–7.5 kW — a torque density comparable to much larger parallel-shaft units. The perpendicular input-to-output layout is inherently suited to machine geometries where the motor and driven shaft cannot share the same axis, eliminating additional bevel stages or chain-and-sprocket drives that add cost and maintenance.
By pre-reducing speed in the helical stage before it reaches the worm mesh, the EP-S77 reduces worm sliding velocity at any given overall ratio. Lower sliding velocity directly reduces worm-mesh friction noise, yielding typical noise levels 6–10 dB(A) below equivalent single-stage worm reducers — an advantage valued in food production halls, pharmaceutical facilities, and any environment with operator occupancy near the drive.
Ratios from 8.74 to 196.11 in a single housing are achievable with the EP-S77, covering applications from moderately fast conveyor drives at the lower end to very slow-rotation stirring and positioning drives at the upper end. This breadth eliminates the need to cascade multiple reducers in most applications, simplifying the drivetrain and reducing total installation length.
Five structural types — S, SF, SA, SAF, SAT — plus the SA-SZ input shaft variant address every practical machine interface without custom engineering. SA and SAF hollow-bore types allow direct shaft mounting, eliminating flexible couplings and their associated alignment requirements. The SAT torque-arm type simplifies drum and conveyor installations further by reacting torque through a single rubber-buffered arm rather than a rigid baseplate.
The EP-S77 worm wheel is manufactured from centrifugally cast phosphor-bronze (ZCuSn10P1), chosen for its combination of high load capacity, low friction against hardened steel, and resistance to adhesive wear under boundary-lubrication conditions during start-up. The hardened and profile-ground worm shaft (Ra ≤ 0.4 µm) maintains an elastohydrodynamic oil film across the full operating speed range, extending tooth-surface life to typically 25,000–40,000 hours.
Structural Type Diagrams — S77 Series
Use the diagrams below to confirm the external geometry, mounting interface, and connection dimensions of each S77 structural type before finalising your machine design. Certified dimensional drawings in DXF and PDF are available on request.
S77 Foot-Mount, Solid Output Shaft
SF77 B5 Flange, Solid Output Shaft
SA77 Shaft-Mounted, Hollow Bore
SAF77 B5 Flange + Hollow Bore
SAT77 Torque-Arm, Hollow Bore
SA77-SZ Input Shaft Only
Industry Applications — Where the EP-S77 Excels
| Industry Sector | Typical Application |
|---|---|
| Clay extruder head drives, glaze-application conveyor units, and tile press feed drives. | |
| Plastics Industry | Injection moulding machine auxiliary drives, pelletiser cutter heads, and film-winding tension systems. |
| Grain Handling | Grain auger metering drives, seed-cleaning screen oscillators, and silo sweep drives. |
| Wastewater Treatment | Slow-speed rotating distributor arms, filter-press belt advance drives, and chemical dosing pump agitators. |
Application Case Study: Plastic Pelletiser Head Drive
A plastics compounder required a compact right-angle drive for the cutter-head of a strand pelletiser processing glass-fibre-filled nylon at 180 rpm. An EP-S77 with a 4 kW, 4-pole motor delivered the required 11.2:1 reduction. After 18 months of continuous two-shift operation in a 38 °C ambient, the housing oil temperature stabilised at 72 °C — 8 °C below the 80 °C limit specified by the customer.
Model Designation Guide — How to Order an EP-S77
Every element of the S-series order code defines a specific product attribute. The example below shows a 1.5 kW, torque-arm, hollow-bore unit in mounting position M1:
EP – S77 – SAT – Y – 2 – 1.5 – 4P – M1
| Code Element | Meaning |
|---|---|
| EP | Brand identifier — Ever Power |
| S77 | Series and frame size — S-series helical-worm |
| SAT | Structural type: torque-arm, hollow-bore output |
| Y | Motor type: Y-series IEC standard induction motor |
| 2 | Number of gear stages (helical + worm) |
| 1.5 | Motor rated power in kW |
| 4P | Motor pole count (1,450 rpm at 50 Hz) |
| M1 | Mounting position (1 of 6 standard positions) |
Frequently Asked Questions — EP-S77
What distinguishes the EP-S77 from the EP-S67 in terms of application?
The EP-S77 offers approximately 69% more output torque (1,350 vs 800 N·m) and a higher radial shaft load rating (12,500 vs 8,000 N), making it the choice when the S67 is undersized under moderate shock or continuous heavy-duty conditions. The S77 is also available with a wider range of motor flanges up to IEC 132 frame, suiting larger motorisation requirements.
Can the EP-S77 drive a vertical screw conveyor (shaft pointing upward)?
Yes. The M3 (output shaft pointing up) and M4 (output shaft pointing down) mounting positions are standard. For M3/M4 mounting, the oil fill level and vent plug position differ from horizontal — consult the mounting-position lubrication chart in the manual. The SAT77 torque-arm variant is especially convenient for vertical screw conveyors because it eliminates the external torque-reaction bracket that foot-mount units require.
What surface temperature can be expected on the EP-S77 housing at full load?
At rated load and 25 °C ambient, the EP-S77 housing surface typically reaches 55–65 °C steady state. CE Machinery Directive surface-temperature labelling requires a warning label above 70 °C — the EP-S77 remains below this threshold under standard conditions. For hot ambient (above 35 °C), a synthetic lubricant upgrade is recommended to keep temperatures in range.
What are the minimum order and lead time requirements for the EP-S77?
Minimum transaction value is USD 1,500; 1–5 evaluation units accepted. Standard units ship in 10–25 working days; custom configurations (including ATEX, special bore, or non-standard ratio) require 20–45 working days. Standard trade terms: EXW, FOB, CIF, DAP. DDP negotiable for most destinations. Contact our team for freight and customs advisory for your country.
Does the EP-S77 offer a self-locking feature?
The EP-S77 provides output-shaft self-locking (holds position without a brake) at ratios above approximately 55:1 when driven from the output side. At lower ratios, or if holding load against gravity during power-off periods is required, add a motor-integrated or shaft-mounted spring brake. We can assist with sizing the appropriate brake torque for your load.
Built for Continuous-Duty Industrial Production
The EP-S77 is designed for the duty profiles that expose weaknesses in under-specified drives: extended hours, fluctuating load, and environments that preclude frequent maintenance. Ever Power backs every EP-S77 with a full technical datasheet, installation manual, and application engineering support. See our quality credentials, then get in touch for pricing.