As a comparison of the motor speed-torque performance, the BE servo motors have just as much continuous torque and hold it for higher speeds and also has intermittent peak torque range allowing for higher performance and/or overcoming static friction (stiction).
Note: Click on images below to enlarge.
1. BE servo motor shaft size is larger diameter and longer on the 23frame. Pilot and bolt circle diameters are still Nema23 / Nema34 so only the pulley or coupling would need to be modified or changed.
The BE23 motor shaft is 0.375-in diameter (9.51 mm) x 1.25-in long (31.9 mm). The 23frame S57/ZETA57/ES2x is 0.25-in diameter (6.35 mm) x 0.81-in long (20.6 mm)
The BE34 motor shaft is 0.50-in diameter (12.7 mm) x 1.19-in long (30.3 mm). The 34frame S83/ZETA83/ES3x is 0.375-in diameter (9.525 mm) x 1.19-in long (30.3 mm)
2. BE servo motor is physically longer.
The BE servo motor is longer to accommodate the feedback within the servo motor design. See catalog specs.
3. Different cable options
The BE servo motors have several standard connector options.
The PS connector option is our standard option with servo cables that plug right into the motor and connectorized for the IPA. This provides the best grounding and is IP67 rated with the mating connectors. If the cables wear over time, the cables can easily be replaced rather than having to replace the motor and cable with the 10 cable option. However, the connectors are straight connectors and do stick out from the motor significantly compared to the bend radius of the S step motors cable.
The 10 cable option is a 10-foot (3m) that would be most like what's on the S series step motors. However, there's no connector on the end and the IPA encoder input is a 15pin high density connect (15pin Dsub). A VM15-MC-02 could be used but that's a poor choice as the shield on the 10 cable option must be connected at the IPA.
We can offer as custom the 10 cable option with a 15pin D-sub on the end for the IPA, or right-angle rotatable PS connectors on the motor (same as what's on our MPP/MPJ motors).
4. Stepper applications were traditionally sized for a 50% torque margin where servo motors sized for a 20% torque margin. The Zeta and Gemini Steppers with their advanced smoothing features allowed running closer to the edge of the speed torque curves but many times were used as an upgrade from older stepper drives (S series, A series, etc) that didn't have the performance of the Zeta/Gemini. Checking the motor sizing can confirm the right size motor is being used. Our local Parker ATCs have automation engineers on staff that can review the loads & speeds and re-size the motor.
The S57-51 is same as the ZETA57-51 motor is the same as the ES21B:
The S57-83 is same as the ZETA57-83 motor is the same as the ES22B:
The S57-102 is same as the ZETA57-102 motor is the same as the ES23B:
The S83-62 is same as the ZETA83-62 motor is the same as the ES31B:
The S83-93 is same as the ZETA83-93 motor is the same as the ES32B:
The S83-135 is same as the ZETA83-135 motor is the same as the ES33B: