USAFED-20FA2S belongs to discontinued Yaskawa F-series VS800 permanent magnet AC servo motor lineup, specifically developed to match customized CACR-SR50 series servo amplifiers with dedicated Y-suffix locked firmware versions for traditional CNC machine feed axis control. This unit adopts fully enclosed natural air-cooled construction without built-in electromagnetic brake, designed for medium-heavy load cyclic start-stop operation and high-precision continuous positioning tasks on CNC lathes, machining centers and automated special-purpose machinery. The trailing S stands for factory-customized incremental encoder wiring definition, which restricts normal closed-loop operation only with paired modified servo drives instead of standard universal CACR servo packs.

USAFED represents Yaskawa fully enclosed F-type CNC exclusive servo motor series; numeric code 20 corresponds to 1.8kW rated power specification; letter F means natural casing self-cooling without external cooling fan; letter A indicates non-brake internal structure with no power-off holding brake assembly; digit 2 denotes keyed solid output shaft with standard shaft keyway; suffix S refers to custom-configured UTOPI incremental encoder and fixed pin assignment exclusive for designated customized servo controllers.

The motor is rated for three-phase AC200V~230V 50/60Hz industrial input power supply. Its continuous rated output power reaches 1.8kW with full-load rated operating current of 15A, fixed rated rotational speed at 1500rpm and continuous rated output torque up to 11.5Nm; instantaneous peak overload torque can reach three times of rated torque within short duration to satisfy heavy-load startup and high-acceleration working requirements. It is equipped with UTOPI-600UB differential line-drive incremental rotary encoder delivering 6000 pulses per revolution feedback signal, the S-type factory fixed encoder protocol can only match dedicated customized CACR-SR50 servo drivers while standard non-modified servo amplifiers fail to complete normal closed-loop positioning control. Stator winding is manufactured under Class F insulation standard to maintain stable dielectric performance under long-hour continuous full-load running status.

Whole motor housing adopts fully enclosed structure with IP50 ingress protection grade and relies entirely on shell natural convection heat dissipation without auxiliary cooling fan setup. Output shaft is solid keyed shaft with standard built-in keyway, differing from smooth shaft variant FA1 series motors; without rear brake housing, the overall axial dimension is shorter than brake-equipped FB/FC type counterparts such as USAFED-20FB2S. The net weight of the servo motor is around 7.2kg with standard flange mounting dimension for direct coupling with ball screw or speed reducer of machine tool feed axes. Allowable working ambient temperature ranges from 0℃ to +40℃, permissible storage temperature covers -20℃ to +70℃, and applicable working relative humidity is limited within 5%~80%RH with no dew condensation permitted inside casing. When installation elevation exceeds 1000 meters above sea level, continuous output load needs proper derating to avoid overheating damage during long-time operation. Working surroundings containing corrosive gas, heavy dust or continuous liquid splashing are prohibited strictly, and the unit can withstand working vibration of 10Hz~55Hz with vibration amplitude lower than 0.5mm.

This servo motor exclusively matches Yaskawa customized CACR-SR50 series servo packs with Y-code modified firmware; conventional non-custom CACR drivers cannot realize complete encoder matching and closed-loop control due to S-suffix exclusive encoder definition and internal parameter locking. Two mainstream command control modes are available via matched servo amplifier: ±10V analog voltage speed control instruction and differential pulse position command transmitted from external CNC controller, meeting diverse speed regulation and high-repeat-precision positioning demands of numerical control processing equipment. Since there is no integrated built-in holding brake inside the motor, external mechanical locking fixture is required for vertical axis anti-drop fixation once main power supply cuts off.

Built-in stator winding temperature detection circuit transmits overheat alarm signal to matched servo drive to trigger automatic overload protection. Common abnormal faults correspond to fixed servo panel alarm codes: encoder cable open or disconnection triggers fault No.6, long-term continuous overload operation activates fault No.7, and stator winding short-circuit overcurrent leads to fault No.1 alert on driver display. No brake coil related failure alarm will occur thanks to non-brake internal structure design of this FA model motor. Internal circuit layout is equipped with surge suppression components to improve anti-interference capability against instantaneous power fluctuation on industrial site.

Direct field replacement requires identical original USAFED-20FA2S model; alternative specifications including brake-type FB variant or non-key shaft FA1 series cannot substitute directly unless paired servo drive completes factory firmware rewrite and full parameter resetting. Before any disassembly for bearing inspection or encoder maintenance work, fully cut off three-phase main power and wait over 15 minutes for servo internal DC bus capacitor full discharge to prevent electric shock risk. Routine maintenance items include fastening encoder wiring terminals every three months and supplementing bearing lubricating grease after every 8000 cumulative running working hours; arbitrary alteration of internal encoder pin definition or motor power wiring will result in servo runaway and permanent driver fault lockout.

Primarily applied for X/Y/Z horizontal feed axis driving of medium and large CNC lathes, vertical machining centers, automatic feeding production lines and non-standard customized heavy-load automation equipment, especially suitable for medium-heavy load frequent forward-reverse cycling operation and high-precision repetitive positioning machining working scenarios.