
B–65160E/02
2. FUNCTION EXPLANATION
FANUC AC SPINDLE MOTOR a series
55
When spindle orientation is started when the speed is within the range
between the zero speed detection level and the orientation speed,
overshoot may occur upon orientation stop. This may be prevented by
specifying 50 msec or more in the parameter.
(1) When the spindle orientation speed (parameter No. 4038) is set to 0,
the orientation speed is determined using the following expression:
Nori + 60 PG Rori GEAR
where,
Nori : Orientation speed (motor speed) [min
–1
]
Rori : Motor speed limit ratio for orientation
(parameter No. 4076)
PG : Position gain for orientation [sec
–1
]
(parameter Nos. 4060 to 4063)
GEAR : Spindle–to–motor gear ratio
(Parameter Nos. 4056 to 4059)
(2) The position gain for spindle orientation is obtained using the
following expression:
PG x
Tm
2p (Jm ) Jl) Rori GEAR
where,
PG : Position gain for orientation [sec
–1
]
(parameter Nos. 4060 to 4063)
Tm : 30–min rated torque [Nm] for the motor when rotating at
Nori [min
–1
]
Jm : Rotor inertia [kg m
2
]
Jl : Load inertia converted to motor shaft inertia [kg m
2
]
Rori : Motor speed limit ratio for orientation
(parameter No. 4076)
GEAR : Spindle–to–motor gear ratio
(parameter Nos. 4056 to 4059)
(3) Calculation example when motor model 6 is being used alone)
Tm +
7500 [W]
1500 [min
–1
] 1.0269
+ 4.86 [Nm]
Jm + 0.0022 [kg m
2
]
Rori + 33 [%]
N PG x
486
2p 0.0022 0.33
+ 32 [sec
–1
]
2.1.5
Calculating the
Position Gain for
Orientation