Intermittent Load Operating Capacity - YASKAWA VS-626M5 Instruction Manual

Appendix

15.3.4 Intermittent Load Operating Capacity

15.3.4 Intermittent Load Operating Capacity
15
If operations, such as tapping a machine-tool or driving a conveyer table, are frequently reversed, care must
be taken in selecting the capacity. When using an operation cycle that includes acceleration/deceleration
operations such as those shown in Fig. 15.19, make a selection so that the motor equivalence efficiency
torque T is less than the inverter continuous rated torque. (The maximum value of T
R
the Inverter 30 min. rating.)
2 (t + t ) + T 2
T t
P r f L s
T = (N
R
t
C
Motor torque
Motor speed
Fig 15.19 Motor Torque and Speed Timechart
The motor reverse rating is the rating over the load where the motor load changes cyclically. When the
reverse rated output is taken to be t
formula is called %ED (Einschalt Dauer). t
t
1
× 100
α = (%)
t + t
1 2
m)
•
T
T
P
L
t t
t
r s −T
f
P
t
c
N
M
, and with no load is taken to be t
1
+ t is regulated to 10 minutes.
1 2
15 -18
will be 120% of
P
Time
Time
, a as expressed in the following
2