Fuji Electric FRENIC-Ace series, Руководство пользователя

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10.3 Equations for Selections
10-12
Before proceeding this calculation, obtain the motor shaft moment of inertia J
1
, the load shaft moment of inertia
converted to motor shaft J
2
, maximum load torque converted to motor shaft τ
L
, and the reduction-gear efficiency η
G
.
Apply the maximum motor output torque τ
M
according to an actual speed thread Δ N as follows.
[ τ
M
in N ≤ N
0
] Constant output torque range
) m N (
N 2
P 60
0
0
M
･
･
･
π
= τ
(Equation 10.3-18)
[ τ
M
in N
0
≤N ≤ N
1
] Constant output power range
(The motor output torque is inversely proportional to the motor speed)
) m N (
N 2
P 60
0
M
･
･
･
π
= τ
(Equation 10.3-19)
If the result obtained by the above calculation does not satisfy the target value, select an inverter with one rank
higher capacity.
[ 5 ] Calculating non-linear deceleration time
Use the following expression to obtain the non-linear deceleration time as well as for the acceleration time.
) s (
60
N 2
J J
t
G L M
G
2 1
DEC
D π
η τ τ
η
+
= D
•
•
•
•
−
(Equation 10.3-20)
In this expression, both τ
M
, and Δ N are generally negative values so that the load torque τ
L
serves to assist the
deceleration operation. For a lift load, however, the load torque τ
L
is a negative value in some modes. In this case,
the τ
M
, and τ
L
will take polarity opposite to each other and the τ
L
will actuate to prevent the deceleration operation of
the lift.