{"id":762,"date":"2026-06-03T02:25:31","date_gmt":"2026-06-03T02:25:31","guid":{"rendered":"https:\/\/planetary-gearboxes.com\/?p=762"},"modified":"2026-06-03T02:25:31","modified_gmt":"2026-06-03T02:25:31","slug":"how-to-select-precision-planetary-gearbox-5-steps","status":"publish","type":"post","link":"https:\/\/planetary-gearboxes.com\/ru\/how-to-select-precision-planetary-gearbox-5-steps\/","title":{"rendered":"\u041a\u0430\u043a \u0432\u044b\u0431\u0440\u0430\u0442\u044c \u043f\u0440\u0435\u0446\u0438\u0437\u0438\u043e\u043d\u043d\u044b\u0439 \u043f\u043b\u0430\u043d\u0435\u0442\u0430\u0440\u043d\u044b\u0439 \u0440\u0435\u0434\u0443\u043a\u0442\u043e\u0440: \u043f\u043e\u0448\u0430\u0433\u043e\u0432\u043e\u0435 \u0440\u0443\u043a\u043e\u0432\u043e\u0434\u0441\u0442\u0432\u043e \u0438\u0437 5 \u0448\u0430\u0433\u043e\u0432, \u0432\u043a\u043b\u044e\u0447\u0430\u044f \u0444\u0430\u043a\u0442\u043e\u0440 \u043e\u0431\u0441\u043b\u0443\u0436\u0438\u0432\u0430\u043d\u0438\u044f, \u043a\u043e\u0442\u043e\u0440\u044b\u0439 \u0431\u043e\u043b\u044c\u0448\u0438\u043d\u0441\u0442\u0432\u043e \u0438\u043d\u0436\u0435\u043d\u0435\u0440\u043e\u0432 \u043f\u0440\u043e\u043f\u0443\u0441\u043a\u0430\u044e\u0442."},"content":{"rendered":"
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<\/div>\n

Korea Ever-Power \u00b7 Engineering Guide<\/p>\n

\u041a\u0430\u043a \u0432\u044b\u0431\u0440\u0430\u0442\u044c \u043f\u0440\u0435\u0446\u0438\u0437\u0438\u043e\u043d\u043d\u044b\u0439 \u043f\u043b\u0430\u043d\u0435\u0442\u0430\u0440\u043d\u044b\u0439 \u0440\u0435\u0434\u0443\u043a\u0442\u043e\u0440: \u043f\u043e\u0448\u0430\u0433\u043e\u0432\u043e\u0435 \u0440\u0443\u043a\u043e\u0432\u043e\u0434\u0441\u0442\u0432\u043e \u0438\u0437 5 \u0448\u0430\u0433\u043e\u0432, \u0432\u043a\u043b\u044e\u0447\u0430\u044f \u0444\u0430\u043a\u0442\u043e\u0440 \u043e\u0431\u0441\u043b\u0443\u0436\u0438\u0432\u0430\u043d\u0438\u044f, \u043a\u043e\u0442\u043e\u0440\u044b\u0439 \u0431\u043e\u043b\u044c\u0448\u0438\u043d\u0441\u0442\u0432\u043e \u0438\u043d\u0436\u0435\u043d\u0435\u0440\u043e\u0432 \u043f\u0440\u043e\u043f\u0443\u0441\u043a\u0430\u044e\u0442.<\/h1>\n

A Korean automotive Tier-1 supplier \u2014 evaluating a \u043f\u0440\u0435\u0446\u0438\u0437\u0438\u043e\u043d\u043d\u044b\u0439 \u043f\u043b\u0430\u043d\u0435\u0442\u0430\u0440\u043d\u044b\u0439 \u0440\u0435\u0434\u0443\u043a\u0442\u043e\u0440<\/strong> for a servo press transfer axis \u2014 lost 43 hours of production across two press lines in 2023. Root cause: a planetary gear reducer specified at exact rated torque with no service factor applied. Eight months later, early pitting on the planet gear flanks had doubled the backlash and the gearbox seized during a direction reversal. This guide gives you the complete five-step framework \u2014 so that failure case never applies to your machine.<\/p>\n

Get Free Gearbox Selection Support \u2192<\/a><\/p>\n<\/div>\n<\/section>\n

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The Five-Step Selection Framework at a Glance<\/h2>\n

\u0410 \u043f\u0440\u0435\u0446\u0438\u0437\u0438\u043e\u043d\u043d\u044b\u0439 \u043f\u043b\u0430\u043d\u0435\u0442\u0430\u0440\u043d\u044b\u0439 \u0440\u0435\u0434\u0443\u043a\u0442\u043e\u0440<\/strong> sits directly between your servo motor and the machine load. Every mismatch in that interface \u2014 torque, inertia, configuration, or IP rating \u2014 is amplified through every cycle the machine runs. The five-step process below is the minimum rigorous approach. Steps 1 and 2 are where most early failures originate; Steps 4 and 5 are where installation problems begin.<\/p>\n

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01<\/div>\n
Load Profile & Duty Cycle<\/div>\n
Define continuous torque, peak torque, shock class, and duty cycle percentage. This is the foundation every other step builds on.<\/div>\n<\/div>\n
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02<\/div>\n
Required Output Torque + SF<\/div>\n
Apply the service factor (SF) to your calculated torque before sizing. Skipping this single step causes approximately 40% of premature gearbox failures in servo applications.<\/div>\n<\/div>\n
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03<\/div>\n
Gear Ratio & Inertia Match<\/div>\n
Calculate the reflected inertia at each candidate ratio. Target a motor-to-reflected-load inertia ratio of 1:1 to 3:1 for stable servo tuning.<\/div>\n<\/div>\n
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04<\/div>\n
Configuration Selection<\/div>\n
Choose inline or right-angle input, round or square output flange, based on installation geometry, available depth, and machine structure.<\/div>\n<\/div>\n
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05<\/div>\n
Motor Interface Verification<\/div>\n
Confirm input flange size, shaft diameter tolerance, input speed limit, IP rating, and mounting orientation before finalising the order.<\/div>\n<\/div>\n<\/div>\n<\/section>\n

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\"Korea<\/p>\n
Korea Ever-Power EP series \u2014 five configurations covering inline, right-angle, round flange, square flange, and high-stiffness IP65 variants. Browse the full EP planetary gearbox range \u2192<\/a><\/div>\n<\/div>\n

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Step 1 \u2014 Define Your Load Profile and Duty Cycle<\/h2>\n

Most engineers start a \u043f\u043b\u0430\u043d\u0435\u0442\u0430\u0440\u043d\u044b\u0439 \u0440\u0435\u0434\u0443\u043a\u0442\u043e\u0440<\/strong> selection by asking what the rated continuous torque of their servo motor is, and then directly match a gearbox to that number. That approach is incomplete. What the gearbox must actually survive is the full shape of the torque demand over time \u2014 not just the average.<\/p>\n

Before calculating a single number, document the following four elements of your load profile:<\/p>\n

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Continuous Torque T_cont<\/div>\n

The torque the load demands during sustained steady-state operation. For a robot arm at constant velocity, this is the gravitational torque plus friction. This value sets the thermal sizing floor.<\/p>\n<\/div>\n

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Peak Torque T_peak<\/div>\n

The maximum torque demanded during acceleration, deceleration, or impact. For servo axes with fast positioning cycles, this is often 2\u20134\u00d7 continuous torque. The gearbox instant stop rating must exceed this.<\/p>\n<\/div>\n

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Shock Load Class<\/div>\n

IEC and DIN standards classify shock loads into three levels. Light shock (uniform conveyor belt) applies SF=1.0\u20131.25. Moderate shock (indexing table with direction reversals) applies SF=1.5\u20132.0. Heavy shock (impact press, robot collision stop) applies SF=2.0\u20132.5.<\/p>\n<\/div>\n

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Duty Cycle ED%<\/div>\n

The percentage of each cycle during which the motor applies torque. A 60% duty cycle with a 5-second period means 3 seconds on, 2 seconds off. This determines thermal load on the gearbox and lubricant, especially in sealed lifetime-lubricated units.<\/p>\n<\/div>\n<\/div>\n

\n\n\n\n\n\n\n\n\n\n
Application Type<\/th>\nShock Class<\/th>\nTypical ED%<\/th>\n\u0420\u0435\u043a\u043e\u043c\u0435\u043d\u0434\u0443\u0435\u043c\u044b\u0439 SF<\/th>\n<\/tr>\n<\/thead>\n
Single-direction conveyor, fan, pump<\/td>\n\u0421\u0432\u0435\u0442<\/td>\n80\u2013100%<\/td>\n1.0\u20131.25<\/td>\n<\/tr>\n
AGV drive wheel, packaging line servo axis<\/td>\nLight\u2013Moderate<\/td>\n50\u201380%<\/td>\n1.25\u20131.5<\/td>\n<\/tr>\n
CNC rotary axis, indexing table, robot arm joint<\/td>\n\u0423\u043c\u0435\u0440\u0435\u043d\u043d\u044b\u0439<\/td>\n30\u201360%<\/td>\n1,5\u20132,0<\/td>\n<\/tr>\n
Press line transfer, collision-rated robot axis<\/td>\nModerate\u2013Heavy<\/td>\n20\u201350%<\/td>\n2,0\u20132,5<\/td>\n<\/tr>\n
Servo press main drive, heavy-impact transfer<\/td>\n\u0422\u044f\u0436\u0435\u043b\u044b\u0439<\/td>\n<30%<\/td>\n2.5+<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/section>\n

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Step 2 \u2014 Calculate Required Output Torque with Service Factor (The Step Most Engineers Skip)<\/h2>\n

The service factor (SF) is not a bureaucratic safety margin added by cautious engineers. It accounts for three real physical phenomena that a simple rated-torque calculation cannot capture: load variations that are faster than the servo’s closed-loop response, thermal effects on lubricant film strength under varying duty cycles, and duty cycle asymmetries between acceleration and deceleration phases that create cumulative bearing fatigue loads exceeding what steady-state continuous torque implies.<\/p>\n

Skipping the service factor is the single most common cause of early-life gearbox failure in servo automation systems<\/strong>, responsible for approximately 40% of premature failures in high-cycle servo applications.<\/p>\n

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Core Torque Selection Formula<\/div>\n
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T_motor_out = 9550 \u00d7 P_motor(kW) \u00f7 n_motor(rpm)<\/div>\n
T_gearbox_out = T_motor_out \u00d7 i \u00d7 \u03b7<\/div>\n
T_required = T_gearbox_out \u00d7 \u0421\u0430\u043d-\u0424\u0440\u0430\u043d\u0446\u0438\u0441\u043a\u043e<\/strong> \u00a0\u2190\u00a0 the step most skip<\/div>\n
where: i = gear ratio, \u03b7 = gearbox efficiency (0.96 single-stage, 0.94 two-stage, 0.90 three-stage)<\/div>\n
Select gearbox rated torque \u2265 T_required<\/div>\n<\/div>\n<\/div>\n

Worked Example \u2014 Automotive Transfer Robot J2 Arm Axis<\/h3>\n

A Korean automotive body-shop supplier needs a servo gearbox for a 6-axis transfer robot’s J2 (large-arm) joint. The servo motor is a 1.5 kW unit rated at 3,000 rpm. The machine cycle involves rapid positioning with direction reversals (Moderate\u2013Heavy shock class). Service factor selected: SF = 2.0.<\/p>\n

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Calculation Steps<\/div>\n
T_motor_out = 9550 \u00d7 1.5 \u00f7 3000 = 4.775 N\u00b7m<\/strong><\/div>\n
Target gear ratio: i = 16 (two-stage, for output speed \u2248 188 rpm)<\/div>\n
\u03b7 = 0.94 (two-stage EP-ZDS series)<\/div>\n
T_gearbox_out = 4.775 \u00d7 16 \u00d7 0.94 = 71.9 N\u00b7m<\/strong><\/div>\n
T_required = 71.9 \u00d7 SF(2.0) = 143.8 N\u00b7m minimum rated torque<\/strong><\/div>\n
\u2192 EP-ZDS-115 at 16:1 two-stage<\/a> rated at 260 N\u00b7m \u2713 (instant stop = 520 N\u00b7m)<\/div>\n<\/div>\n
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\u26a0 What happens if SF is skipped in this example?<\/div>\n

Without SF, the engineer selects a gearbox rated for 71.9 N\u00b7m \u2014 a unit in the EP-ZDE-60 range. At the actual peak torque during emergency braking (estimated 2\u00d7 continuous = 143.8 N\u00b7m), the gearbox operates at 200% of its rated load every time the servo triggers an emergency stop. After a few thousand such events, planet gear flank pitting initiates. Backlash grows. By month eight the axis develops oscillation and a full gearbox replacement is required. This is not a hypothetical \u2014 it is the documented failure pattern of the Korean Tier-1 case referenced in the introduction.<\/p>\n<\/div>\n<\/section>\n

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Step 3 \u2014 Gear Ratio Selection and Inertia Matching<\/h2>\n

The gear ratio of a \u0441\u0435\u0440\u0432\u043e\u043f\u043b\u0430\u043d\u0435\u0442\u0430\u0440\u043d\u044b\u0439 \u0440\u0435\u0434\u0443\u043a\u0442\u043e\u0440<\/strong> determines two things simultaneously: the output shaft speed and the reflected inertia of the load as seen by the motor. Getting the torque right but misjudging inertia means your servo drive will struggle to tune correctly \u2014 and may oscillate, overshoot, or trigger overcurrent faults under rapid acceleration even with a mechanically adequate gearbox.<\/p>\n

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Reflected Inertia Formula<\/div>\n
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J_reflected = J_load \u00f7 i\u00b2<\/div>\n
J_total_at_motor = J_motor_rotor + J_reflected + J_gearbox_input<\/div>\n
Target: J_reflected \u00f7 J_motor_rotor = 1:1 to 3:1 (ideal) | <5:1 (acceptable) | >5:1 (servo tuning difficulty)<\/div>\n<\/div>\n<\/div>\n

The table below shows how a change in gear ratio transforms the same load inertia into dramatically different reflected values at the motor shaft. This is why ratio selection is not just a speed calculation \u2014 it is the primary lever for matching servo motor to mechanical load.<\/p>\n

\n\n\n\n\n\n\n\n\n
Gear Ratio i<\/th>\n\u042d\u0442\u0430\u043f<\/th>\nJ_reflected (kg\u00b7m\u00b2) *<\/th>\nInertia Ratio<\/th>\nServo Tuning Status<\/th>\n<\/tr>\n<\/thead>\n
3:1<\/td>\n1<\/td>\n0.00222<\/td>\n2.2 : 1<\/td>\n\u2705 Ideal<\/td>\n<\/tr>\n
5:1<\/td>\n1<\/td>\n0.000800<\/td>\n0.8 : 1<\/td>\n\u2705 Good<\/td>\n<\/tr>\n
10:1<\/td>\n1<\/td>\n0.000200<\/td>\n0.2 : 1<\/td>\n\u26a0\ufe0f Over-geared, slow response<\/td>\n<\/tr>\n
20:1<\/td>\n2<\/td>\n0.000050<\/td>\n0.05 : 1<\/td>\n\u274c Torque underutilised, poor response<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n

* Example: J_load = 0.02 kg\u00b7m\u00b2, J_motor = 0.001 kg\u00b7m\u00b2. Actual values depend on your specific load geometry and motor specification.<\/p>\n

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When inertia ratio exceeds 5:1<\/div>\n

The servo drive’s velocity feedback loop Kv gain is effectively limited. The axis responds sluggishly to velocity commands and overshoots on position stops. Increasing the proportional gain to compensate causes mechanical resonance \u2014 a problem software alone cannot fully solve because it originates in the physics of the drivetrain inertia mismatch.<\/p>\n<\/div>\n

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Single-stage ratio range: 3:1 to 10:1<\/div>\n

For ratios in this range, a single planetary stage (EP-ZDE\/ZDF\/ZDWE\/ZDWF, 1-stage) provides 96% efficiency (inline) or 94% efficiency (right-angle input). This is the preferred range for high-dynamic servo axes \u2014 CNC feed axes, laser cutting heads, and pick-and-place robots \u2014 where both inertia ratio and efficiency matter equally.<\/p>\n<\/div>\n

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Two-stage ratio range: 9:1 to 100:1<\/div>\n

Two-stage units are appropriate when output speed must be very low (<200 rpm) at rated motor speed. Efficiency drops to 94% (inline) or 92% (right-angle). Acceptable for AGV drive wheels, pallet changers, and solar trackers where efficiency loss is less critical than the high ratio for torque multiplication. Backlash is slightly wider than single-stage.<\/p>\n<\/div>\n<\/div>\n<\/section>\n

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Step 4 \u2014 Choose the Right Configuration (Inline vs Right-Angle, Round vs Square Flange)<\/h2>\n

The Korea Ever-Power EP series of precision planetary gearboxes<\/strong> offers four physical configurations across five product lines. Each solves a specific combination of installation constraints. This is a structural decision \u2014 not a performance preference \u2014 driven by your machine geometry and available machine shop operations.<\/p>\n

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Configuration Decision Tree<\/div>\n
Q1: Is axial depth behind the output face constrained?<\/div>\n
\u251c\u2500\u2500 NO \u2192 Motor can be coaxial with output \u2192 Inline Input (ZDE or ZDF)<\/span><\/div>\n
\u2514\u2500\u2500 YES (motor won’t fit inline) \u2192 Right-Angle Input (ZDWE or ZDWF)<\/span><\/div>\n
Q2 (for inline): Is a precision bore available in your machine structure?<\/div>\n
\u251c\u2500\u2500 YES \u2192 EP-ZDE (round flange, bore mount)<\/a><\/div>\n
\u2514\u2500\u2500 NO \u2192 EP-ZDF (square flange, 4-bolt flat plate)<\/a><\/div>\n
Q2 (for right-angle): Is a precision bore available?<\/div>\n
\u251c\u2500\u2500 YES \u2192 EP-ZDWE (right-angle, round flange)<\/a><\/div>\n
\u2514\u2500\u2500 NO \u2192 EP-ZDWF (right-angle, square flange \u2014 most versatile installation)<\/a><\/div>\n
Q3 (for any config): Does output torque exceed 800 N\u00b7m OR axial force exceed 3,000 N OR IP65 required?<\/div>\n
\u2514\u2500\u2500 YES on any \u2192 EP-ZDS (high-stiffness, IP65, up to 1,800 N\u00b7m)<\/strong><\/div>\n<\/div>\n
\n\n\n\n\n\n\n\n\n\n
\u0420\u044f\u0434<\/th>\nMotor Input<\/th>\n\u0412\u044b\u0445\u043e\u0434\u043d\u043e\u0439 \u0444\u043b\u0430\u043d\u0435\u0446<\/th>\nMax Torque<\/th>\nIP<\/th>\nBest For<\/th>\n<\/tr>\n<\/thead>\n
EP-ZDE<\/strong><\/td>\n\u0412 \u0441\u043e\u043e\u0442\u0432\u0435\u0442\u0441\u0442\u0432\u0438\u0438<\/td>\nRound \u03a6<\/td>\n800 N\u00b7m<\/td>\nIP54<\/td>\nStandard precision servo axes \u2014 CNC, robot, laser cutter<\/td>\n<\/tr>\n
EP-ZDF<\/strong><\/td>\n\u0412 \u0441\u043e\u043e\u0442\u0432\u0435\u0442\u0441\u0442\u0432\u0438\u0438<\/td>\nSquare \u25a1<\/td>\n800 N\u00b7m<\/td>\nIP54<\/td>\nPlate-mount frames \u2014 no boring needed<\/td>\n<\/tr>\n
EP-ZDWE<\/strong><\/td>\n90\u00b0 bevel<\/td>\nRound \u03a6<\/td>\n800 N\u00b7m<\/td>\nIP54<\/td>\n30\u201350% shorter axial depth \u2014 compact machine heads<\/td>\n<\/tr>\n
EP-ZDWF<\/strong><\/td>\n90\u00b0 bevel<\/td>\nSquare \u25a1<\/td>\n800 N\u00b7m<\/td>\nIP54<\/td>\nAGV\/AMR low-profile chassis, welded frames<\/td>\n<\/tr>\n
EP-ZDS<\/strong><\/td>\n\u0412 \u0441\u043e\u043e\u0442\u0432\u0435\u0442\u0441\u0442\u0432\u0438\u0438<\/td>\nSquare \u25a1<\/td>\n1,800 N\u00b7m<\/td>\nIP65<\/td>\nHeavy robot joints, press drives, food processing, washdown<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n
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Right-angle input efficiency trade-off (ZDWE\/ZDWF):<\/strong> The 90\u00b0 bevel gear input stage adds approximately 2% efficiency loss compared to an inline unit of the same frame size. For a 750 W servo motor running 16 hours per day, this equates to approximately 15 W additional heat generation \u2014 negligible for most applications. For continuous 24\/7 high-power operation, verify thermal budget using the formula: P_heat = P_input \u00d7 (1 \u2212 \u03b7), where \u03b7 = 0.92 for ZDWE\/ZDWF two-stage.<\/p>\n<\/div>\n<\/section>\n

<\/p>\n

\"Types<\/p>\n
EP series covers all major configuration types. Need help choosing?<\/div>\n<\/div>\n

<\/p>\n

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Step 5 \u2014 Motor Interface Verification: The 12-Point Checklist<\/h2>\n

\u0410 \u043f\u0440\u0435\u0446\u0438\u0437\u0438\u043e\u043d\u043d\u044b\u0439 \u043f\u043b\u0430\u043d\u0435\u0442\u0430\u0440\u043d\u044b\u0439 \u0440\u0435\u0434\u0443\u043a\u0442\u043e\u0440<\/strong> correctly sized for torque, ratio, and configuration can still fail in service within weeks if the motor-to-gearbox interface is improperly specified. Interface errors typically manifest as elevated vibration, early input bearing failure, and in severe cases, input shaft coupling fracture. This 12-point checklist covers every dimension of the motor-gearbox interface that must be verified before order placement.<\/p>\n

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12-Point Motor Interface Verification Checklist<\/div>\n
\n
\n
01<\/div>\n
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Input Flange Q3 Dimension<\/div>\n
Confirm Q3 (\u25a140 to \u25a1190 mm) matches your servo motor’s face dimensions. EP series uses square input flanges matching IEC motor frame standards.<\/div>\n<\/div>\n<\/div>\n
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02<\/div>\n
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Motor Shaft Diameter & Tolerance<\/div>\n
Gearbox input bore is manufactured to match your motor shaft (h6 or k6 tolerance). Specify motor shaft diameter when ordering \u2014 a generic fit introduces concentricity error >0.02 mm.<\/div>\n<\/div>\n<\/div>\n
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03<\/div>\n
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Motor Shaft Length vs Input Bore Depth<\/div>\n
Motor shaft must be fully engaged to depth L9. If shaft is shorter than bore depth, use a spacer ring. A gap between motor face and gearbox flange concentrates clamping stress.<\/div>\n<\/div>\n<\/div>\n
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04<\/div>\n
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Clamping Input Type (S\/S1\/S2\/K)<\/div>\n
Default S-type (integral locking) works with or without keyway. Specify S2 or K type if your motor shaft has a keyway that must be used for torque locking at high peak loads.<\/div>\n<\/div>\n<\/div>\n
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05<\/div>\n
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Maximum Input Speed<\/div>\n
EP-ZDE\/ZDF\/ZDWE\/ZDWF max: 4,500 rpm (recommended: 3,000 rpm). EP-ZDS-190 max: 3,000 rpm (recommended: 2,000 rpm). Do not exceed rated input speed \u2014 lubricant churning and heat generation increase non-linearly.<\/div>\n<\/div>\n<\/div>\n
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06<\/div>\n
\n
Output Shaft Diameter D4 & Tolerance<\/div>\n
EP series output shafts are h7 tolerance (\u03a610h7 to \u03a655h7 depending on frame). Confirm coupling bore matches D4, and that the coupling is rated for the output torque plus SF.<\/div>\n<\/div>\n<\/div>\n
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07<\/div>\n
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Radial Force at Output Shaft Centre<\/div>\n
Applied radial force at L4\/2 must not exceed rated values (e.g. 900 N for EP-ZDE-80, 12,000 N for EP-ZDS-190). Belt drives, rack-and-pinion, and chain drives add radial load \u2014 calculate and compare.<\/div>\n<\/div>\n<\/div>\n
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08<\/div>\n
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Axial Force at Output Shaft<\/div>\n
Vertical axis gravity loads, thrust-bearing axes, and helical gear axial components all add axial force. EP-ZDE-160 max axial: 3,000 N. If gravity load alone exceeds this, upgrade to EP-ZDS (28,000 N at 190-frame).<\/div>\n<\/div>\n<\/div>\n
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09<\/div>\n
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IP Protection Rating vs Environment<\/div>\n
EP-ZDE\/ZDF\/ZDWE\/ZDWF: IP54 (splash from any direction). EP-ZDS: IP65 (water jet from any direction). If your environment involves direct hose or pressure washing, specify EP-ZDS or confirm with Korea Ever-Power application engineering.<\/div>\n<\/div>\n<\/div>\n
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10<\/div>\n
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Operating Temperature Range<\/div>\n
All EP series: \u221225\u00b0C to +90\u00b0C. Cold-chain and frozen-food applications at \u221220\u00b0C are within spec \u2014 confirm that soft-start is used at start-up in sub-zero environments to allow viscosity normalisation.<\/div>\n<\/div>\n<\/div>\n
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11<\/div>\n
\n
\u041e\u0440\u0438\u0435\u043d\u0442\u0430\u0446\u0438\u044f \u043f\u0440\u0438 \u043c\u043e\u043d\u0442\u0430\u0436\u0435<\/div>\n
All EP series support any mounting orientation \u2014 horizontal, vertical shaft-up, vertical shaft-down, inverted \u2014 without modification. The lifetime-sealed lubricant design eliminates oil level concerns from orientation change.<\/div>\n<\/div>\n<\/div>\n
\n
12<\/div>\n
\n
Backlash vs Application Accuracy Requirement<\/div>\n
Confirm backlash specification matches your positioning accuracy budget. EP-ZDE\/ZDF: <8 arcmin (frame 60\u2013160). EP-ZDWE\/ZDWF: <25\u201330 arcmin. EP-ZDS: <8 arcmin. For the conversion from arcmin to linear error at your load radius, see our backlash guide<\/a>.<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/section>\n

<\/p>\n

\n

Backlash Specification \u2014 Matching Precision Grade to Application Requirement<\/h2>\n

Once torque, ratio, and configuration are confirmed, verify that the backlash specification of the selected precision planetary gearbox is appropriate for your positioning accuracy requirement. Backlash is the angular play at the output shaft when the input direction reverses \u2014 measured in arcminutes (arcmin), where 1 arcmin = 1\/60th of a degree.<\/p>\n

Do not over-specify backlash. A unit with <1 arcmin backlash may cost 3\u20135 times more than a <8 arcmin unit of the same frame size, with no measurable performance benefit in applications that position in a single direction or where the servo closed-loop compensates for the backlash contribution. Match the specification to the actual requirement:<\/p>\n

\n
<8 arcmin (EP-ZDE\/ZDF, frames 60\u2013160)<\/strong>General industrial automation, CNC feed axes, robot joints J3\u2013J6, laser cutting gantry.<\/div>\n
<25\u201330 arcmin (EP-ZDWE\/ZDWF)<\/strong>Right-angle input units \u2014 backlash is wider due to bevel stage. Servo closed-loop fully compensates in position-controlled axes.<\/div>\n
<8 arcmin at 1,800 N\u00b7m (EP-ZDS)<\/strong>High-stiffness series delivers the same sub-8 arcmin precision as EP-ZDE at more than twice the torque capacity.<\/div>\n<\/div>\n<\/section>\n

<\/p>\n

\"Precision<\/p>\n
Correct installation is as important as correct selection. All EP series units ship with full installation documentation.<\/div>\n<\/div>\n

<\/p>\n

\n

Three Sizing Errors That Lead Directly to Early Failure<\/h2>\n
\n
\n
\u2460<\/div>\n
\n
Sizing to rated torque without service factor<\/div>\n

The most frequent error. A gearbox rated at the calculated steady-state output torque appears to match on paper. At the first emergency stop or direction reversal under full load, the actual torque spikes to 2\u20133\u00d7 continuous. Without SF, the unit is operating at 200\u2013300% of its design point. After several thousand such events, planet gear surface fatigue initiates and backlash begins to grow rapidly.<\/p>\n

Fix: Apply SF = 1.5\u20132.5 before selecting rated torque. Use the formula: T_required = T_calculated \u00d7 SF<\/div>\n<\/div>\n<\/div>\n
\n
\u2461<\/div>\n
\n
Inertia ratio exceeding 5:1 without compensation<\/div>\n

When load inertia reflected to the motor exceeds five times the motor rotor inertia, the servo velocity loop becomes difficult to tune. Engineers who push the proportional gain up to compensate create mechanical resonance \u2014 a problem that manifests as axis oscillation, audible vibration, and ultimately early planet carrier bearing fatigue from cyclic overload at the resonant frequency. Software filters help but cannot fully resolve the underlying mechanical mismatch.<\/p>\n

Fix: Calculate J_reflected = J_load \u00f7 i\u00b2 at candidate ratios. If ratio is mechanically constrained, consult motor supplier about higher inertia rotor options.<\/div>\n<\/div>\n<\/div>\n
\n
\u2462<\/div>\n
\n
IP54 gearbox in a washdown or outdoor environment<\/div>\n

An IP54-rated \u043f\u043b\u0430\u043d\u0435\u0442\u0430\u0440\u043d\u044b\u0439 \u0440\u0435\u0434\u0443\u043a\u0442\u043e\u0440<\/strong> resists water splashing from any direction \u2014 but it does not protect against a direct water jet. Korean food-processing facilities under HACCP protocols apply high-pressure hose washing to all machine surfaces including gearboxes. Over 6\u201318 months, even IP54-rated lip seals degrade under repeated chemical cleaning cycles. Water ingress emulsifies the lifetime lubricant, destroying the grease film and dramatically accelerating bearing wear. The gearbox housing temperature rises, the noise increases, and the rated 20,000-hour lifespan may be achieved in under 5,000 hours.<\/p>\n

Fix: Specify EP-ZDS (IP65)<\/strong> for any environment with direct water jet cleaning or sustained moisture exposure.<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/section>\n


\n<\/span><\/p>\n

\n

Selection Summary and Next Steps<\/h2>\n
\n
\n
01<\/div>\n
Document continuous torque, peak torque, shock class, duty cycle<\/div>\n<\/div>\n
\n
02<\/div>\n
Apply service factor SF to required torque before selecting gearbox rating<\/div>\n<\/div>\n
\n
03<\/div>\n
Calculate reflected inertia at each candidate ratio \u2014 confirm ratio keeps inertia ratio \u22643:1<\/div>\n<\/div>\n
\n
04<\/div>\n
Use the configuration decision tree to select EP series and flange type<\/div>\n<\/div>\n
\n
05<\/div>\n
Run through the 12-point interface checklist before submitting order specification<\/div>\n<\/div>\n<\/div>\n
\n
\n
Need Help with Your Specific Application?<\/div>\n

Korea Ever-Power’s application engineering team provides gearbox selection support \u2014 including service factor verification, inertia ratio calculation, and motor interface confirmation \u2014 in Korean and English for Korean OEM manufacturers. Provide your servo motor model, load parameters, and installation constraints to receive a complete selection recommendation at no charge.<\/p>\n<\/div>\n

Contact Application Engineering \u2192<\/a><\/p>\n
sales@planetary-gearboxes.com<\/div>\n<\/div>\n<\/div>\n
\n
Related Korea Ever-Power Planetary Gearbox Series<\/div>\n
\n
\n
\u0421\u0435\u0440\u0438\u044f EP-ZDE<\/div>\n
Round-flange inline input \u00b7 <8 arcmin \u00b7 up to 800 N\u00b7m \u00b7 IP54 \u00b7 5 frame sizes 40\u2013160 mm<\/div>\n

\u041f\u0440\u043e\u0441\u043c\u043e\u0442\u0440\u0435\u0442\u044c \u0442\u0435\u0445\u043d\u0438\u0447\u0435\u0441\u043a\u0438\u0435 \u0445\u0430\u0440\u0430\u043a\u0442\u0435\u0440\u0438\u0441\u0442\u0438\u043a\u0438 \u2192<\/a><\/p>\n<\/div>\n

\n
\u0421\u0435\u0440\u0438\u044f EP-ZDWF<\/div>\n
Square-flange right-angle \u00b7 30\u201350% axial saving \u00b7 no bore required \u00b7 4-bolt plate mount \u00b7 IP54<\/div>\n

\u041f\u0440\u043e\u0441\u043c\u043e\u0442\u0440\u0435\u0442\u044c \u0442\u0435\u0445\u043d\u0438\u0447\u0435\u0441\u043a\u0438\u0435 \u0445\u0430\u0440\u0430\u043a\u0442\u0435\u0440\u0438\u0441\u0442\u0438\u043a\u0438 \u2192<\/a><\/p>\n<\/div>\n

\n
\u0421\u0435\u0440\u0438\u044f EP-ZDS<\/div>\n
IP65<\/strong> \u00b7 up to 1,800 N\u00b7m \u00b7 28,000 N axial \u00b7 130 N\u00b7m\/arcmin stiffness \u00b7 frames 115\u2013190 mm<\/div>\n

\u041f\u0440\u043e\u0441\u043c\u043e\u0442\u0440\u0435\u0442\u044c \u0442\u0435\u0445\u043d\u0438\u0447\u0435\u0441\u043a\u0438\u0435 \u0445\u0430\u0440\u0430\u043a\u0442\u0435\u0440\u0438\u0441\u0442\u0438\u043a\u0438 \u2192<\/a><\/p>\n<\/div>\n<\/div>\n

\u041f\u0440\u043e\u0441\u043c\u043e\u0442\u0440\u0435\u0442\u044c \u0432\u0441\u0435 5 \u0441\u0435\u0440\u0438\u0439 EP \u2192<\/a><\/div>\n<\/div>\n<\/section>\n

\u0420\u0435\u0434\u0430\u043a\u0442\u043e\u0440: Cxm<\/p>\n<\/div>","protected":false},"excerpt":{"rendered":"

Korea Ever-Power \u00b7 Engineering Guide How to Select a Precision Planetary Gearbox: 5-Step Guide Including the Service Factor Most Engineers Skip A Korean automotive Tier-1 supplier \u2014 evaluating a precision planetary gear reducer for a servo press transfer axis \u2014 lost 43 hours of production across two press lines in 2023. Root cause: a planetary […]<\/p>","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_et_pb_use_builder":"","_et_pb_old_content":"","_et_gb_content_width":"","footnotes":""},"categories":[965],"tags":[],"class_list":["post-762","post","type-post","status-publish","format-standard","hentry","category-application-and-technical-guid"],"_links":{"self":[{"href":"https:\/\/planetary-gearboxes.com\/ru\/wp-json\/wp\/v2\/posts\/762","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/planetary-gearboxes.com\/ru\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/planetary-gearboxes.com\/ru\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/planetary-gearboxes.com\/ru\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/planetary-gearboxes.com\/ru\/wp-json\/wp\/v2\/comments?post=762"}],"version-history":[{"count":1,"href":"https:\/\/planetary-gearboxes.com\/ru\/wp-json\/wp\/v2\/posts\/762\/revisions"}],"predecessor-version":[{"id":763,"href":"https:\/\/planetary-gearboxes.com\/ru\/wp-json\/wp\/v2\/posts\/762\/revisions\/763"}],"wp:attachment":[{"href":"https:\/\/planetary-gearboxes.com\/ru\/wp-json\/wp\/v2\/media?parent=762"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/planetary-gearboxes.com\/ru\/wp-json\/wp\/v2\/categories?post=762"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/planetary-gearboxes.com\/ru\/wp-json\/wp\/v2\/tags?post=762"}],"curies":[{"name":"WP","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}