CHAPTER 15 APPENDIXES

(1) Calculating the motor speed (N)

Calculate the motor shaft speed according to the configuration of the machine and the line speed.

(2) Calculating the load inertia (JL)

Calculate the inertia (GD2) of the load of the mechanical system converted to the motor shaft.

Calculate the inertia of the parts rotating (moving) along with motor rotation, and obtain the sum of

all.

(3) Calculating the load torque (TL)

Calculate the load torque converted to the motor shaft.

(4) Temporarily select the motor capacity

Select the motor capacity satisfying the following two conditions.

 Allowable load inertia

JL ≤ JM × 100 (30) ···················· In case of slow travel under speed control

JL ≤ JM × 30 (10) ······················ In case of positioning under position control

JL ≤ JM × 10 (-) ························ In case of frequent positioning

(Approximate measure: Starting and stopping at every 0.5 seconds or more frequently)

Values in parentheses indicate operation with the GYG motor.

 Load torque

TL ≤ TR × 0.9··························· 0.9 indicates a typical margin of safety.

(5) Calculating the shortest acceleration/deceleration time (calculating the accelerating/decelerating

torque)

Check the shortest acceleration/deceleration under consideration of load conditions. If the

acceleration/deceleration time is designated, calculate the acceleration/deceleration torque

(Mechanical efficiency (η)： assuming 100%).

 Shortest acceleration/Deceleration time

tMIN =

(JM + JL) × 2π × (N)

60 (TMAX - TL)

 Acceleration torque

TAC =

TL+

(JM+ JL) × 2π × (N)

60( tAC )

 Deceleration torque

TDC =

TL-

(JM+ JL) × 2π × (N)

60( tDC )

where

tAC : Acceleration time [s]

tDC : Deceleration time[s]

JM : Inertia of servomotor [kgm2]

JL : Inertia of load converted to motor shaft [kgm2]

TL : Load torque converted to motor shaft [Nm]

TAC : Acceleration torque [Nm]

TDC : Deceleration torque [Nm]

TMAX : Max. torque [Nm]

Ｎ : Rotation speed [r/min]

tMIX : Shortest acceleration/deceleration time [s]

15

Capacity Selection Calculation 15-21