FujiFilm FRENIC5000G11S Series, Техническая информация

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Chapter 4
1. Inverter and Motor Selection
4-5
4
(1) Calculation of load torque during constant speed
running (For detailed calculation, see Section 1.3.1)
This step is necessary for capacity selection for all loads.
Determine the rated torque of the motor during constant
speed running higher than that of the load torque, and
select a tentative capacity. To perform capacity selection
efficiently, it is necessary to match the rated speeds (base
speeds) of the motor and load.
To do this, select an appropriate reduction-gear (mechani-
cal transmission) ratio and number of motor poles. If
acceleration/deceleration time is not limited and the
system is not a lifting machine, capacity selection is
completed as it is.
(2) Acceleration time
(For detailed calculation, see Section 1.3.2)
When there are specified requirements for the acceleration
time, calculate it using the following procedure:
q q q q q
Calculate moment of inertia for the load and motor.
Calculate moment of inertia for the load by referring to
Section1.3.2.
w w w w w
Calculate minimum acceleration torque. (See Fig. 4.4)
The acceleration torque is the difference between motor
short time output torque (60s rating) explained in Section
1.1 and load torque (
τ
L
/
η
G
) during constant speed running
calculated in the above
q
. Calculate minimum accelera-
tion torque for the whole range of speed.
e
Calculate the acceleration time.
Assign the value calculated above to the expression
(4.15) in Section 1.3.2 to calculate the acceleration time.
If the calculated acceleration time is longer than the
requested time, select one size larger capacity inverter
and motor and calculate it again.
(3) Deceleration time
(For detailed calculation, see Section 1.3.2)
To calculate the deceleration time, check the motor
deceleration torque characteristics for the whole range of
speed in the same way as for the acceleration time.
q q q q q
Calculate moment of inertia for the load and motor.
Same as for acceleration time.
w w w w w
Calculate minimum deceleration torque.
(See Fig. 4.5)
Same as for deceleration time.
e e e e e
Calculate the deceleration time.
Assign the value calculated above to the expression
(4.16) in Section 1.3.2 to calculate the deceleration time.
If the calculated deceleration time is longer than the
requested time, select one size larger capacity and
calculate it again.
However, note that minimum deceleration torque becomes
smaller due to regenerative operation when lifting or
lowering a load. (See Fig. 4.6)
(4) Braking resistor rating
(For detailed calculation, see Section 1.3.3)
Braking resistor rating is divided into two types according
to the braking periodic duty cycle:
q q
q q
q
When periodic duty cycle is 100s or less:
Calculate average loss to determine rated values.
w w w w w
When periodic duty cycle is 100s or more:
Allowable braking energy depends on maximum braking
power. Allowable values are listed in Chapter 3, Section 4.
(5) Motor RMS current
In metal processing machine and carriage machinery
requiring positioning control, highly frequent running with
short time rating is performed. In this case, calculate an
equivalent RMS current value not to exceed the allowable
value for the motor.
0
speed
Load torque
Minimum acceleration
torque
Load torque at
constant speed
Motor output torque
Torque
τ
M
τ
L
τ
L
η
G
Motor output torque
Speed
Minimum deceleration
torque
Load torque at
constant speed
Load torque
0
Torque
τ
M
τ
L •
τ
L
η
G
0
Motor output torque
τ
M
Speed
Minimum deceleration
torque
Load torque at
constant speed
Load torque
τ
L
Torque
τ
L •
η
G
Fig. 4.4 Example study of minimum acceleration torque
Fig. 4.5 Example study of minimum deceleration torque (1)
Fig. 4.6 Example study of minimum deceleration torque (2)