YASKAWA SGM7J-A5A, Technical Supplement

Page: 594 / 622

Appendices
Capacity Selection for Servo Motors
576
9.
Verification of the Provisionally Selected Servo Motor
•
Verification of required acceleration torque:
•
Verification of required deceleration torque:
• Verification of effective torque value:
It has been verified that the provisionally selected Servo Motor is applicable in terms of capacity. Position
control is considered next.
10.
Positioning Resolution
The electrical stopping precision

is ±0.01 mm, so the positioning resolution is 0.01 mm.
The ball screw lead P
B
is 0.005 m, so the number of pulses per motor rotation is calculated with the follow-
ing formula.
The number of pulses per motor rotation is less than the encoder resolution (pulses/rev), so the
provisionally selected Servo Motor can be used.
11.
Reference Pulse Frequency
The load speed is 15 m/min, or 1,000 × 15/60 mm/s and the positioning resolution (travel distance per
pulse) is 0.01 mm/pulse, so the reference pulse frequency is calculated with the following formula.
The reference pulse frequency is less than the maximum input pulse frequency,* so the provisionally
selected Servo Motor can be used.
* Refer to the specifications in the SERVOPACK manual for the maximum input pulse frequency.
It has been verified that the provisionally selected Servo Motor is applicable for position control.
TP
= +
TL
= + 0.139
≈ 0.552 (N
x
m) < Maximum instantaneous torque...Satisfactory
60 ta
60
×
0.1
2
π ×
3,000
×
(0.0659 + 1.25)
×
10 -4
2
π
nM
(
JM
+
JL
)
TS
=
−
TL
=
−
0.139
60 td
60
×
0.1
2
π ×
3,000
×
(0.0659 + 1.25)
×
10 -4
≈ 0.274 (N
x
m) < Maximum instantaneous torque...Satisfactory
2
π
nM ( JM + JL )
Trms
= =
t
TP
2
x
ta
+
TL
2
x
tc
+
Ts
2
x
td
(0.552) 2
×
0.1 + (0.139) 2
×
0.9 + (0.274) 2
×
0.1
1.5
≈ 0.192 (N
x
m) < Rated torque...Satisfactory
Δ
= = = 500 (pulses/rev) <
Δ
0.01 mm
5 mm/rev
PB
The number of pulses per revolution (pulses) Encoder resolution [16777216 (pulses/rev)]
υ
L
vs
= = = 25,000 (pps)
60
×
1,000
υ
L
60
×
0.01
1,000
×
15
Δ