
2.EXPLANATION OF OPERATION MODES FANUC AC SPINDLE MOTOR αCi series B-65280EN/05
- 418 -
15i 16i 30i
3069 4069 4069
Acceleration/deceleration constant (HIGH) CTH1A=0, CTH2A=0
3070 4070 4070
Acceleration/deceleration constant (MEDIUM HIGH) CTH1A=0, CTH2A=1
3071 4071 4071
Acceleration/deceleration constant (MEDIUM LOW) CTH1A=1, CTH2A=0
3071 4072 4072
Acceleration/deceleration constant (LOW) CTH1A=1, CTH2A=1
Unit of data : 1min
-1
/ sec
Valid data range : 0 to 32767
Standard setting value : 900
These parameters set an acceleration/deceleration constant calculated
from the motor output torque and spindle inertia and adjust
acceleration/deceleration time.
A parameter is selected by the input signals CTH1A and CTH2A. The
initial setting value "900" assumes that linear acceleration/
deceleration is performed with the 30-minute rated torque at the
maximum motor speed, with an inertia three times as large as the rotor
inertia of the motor. It is assumed that all (αCi series spindle motors
satisfy this initial value. So, there is a margin with some motor
models.
For each machine, find a load inertia, and assign the found value to
the following expression to calculate an acceleration/deceleration
constant for setting:
Tc = T/(Jm+Jl) × (60/2π)
= P/N × (60/2π) /(Jm+Jl) × (60/2π)
= P/N/(Jm+Jl) × (60/2π)
2
Tc [min
-1
/sec] : Acceleration/deceleration constant
Jm [kgm
2
] : Motor rotor inertia
Jl [kgm
2
] : Load inertia in terms of motor axis
T [Nm] : 30-minute rated torque
P [kW] : 30-minute rated output
N [min
-1
] : Motor speed
[Rotor inertia and torque data of standard models]
Motor model
αC1i αC2i αC3i αC6i αC8i αC12i αC15i
Rotor inertia Jm
[kgm
2
]
0.003 0.0078 0.0148 0.0179 0.0275 0.07 0.09
30-minute rated
torque at base
speed T [Nm]
14.01 23.55 35.01 47.75 70.03 95.49 117.77
NOTE
1 The initial setting value satisfies a value calculated
with N = maximum speed and Jl = Jm×3.
2 A maximum specifiable acceleration/deceleration
constant is based on N = base speed.