Fuji Electric FRENIC MEGA G2 Series - 5 ] Calculating Non-Linear Deceleration Time

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 
L
, and the reduction-gear efficiency

G
. Apply the maximum motor output torque 
M
according to an actual speed thread ΔN as follows.
[ 
M
in N ≤ N
0
] Constant output torque range
τ
Ｍ
=
60・P
０
(N·m)
(Equation 10.3-18)
2π・N
0
[ 
M
in N
0
≤N ≤ N1] Constant output power range
(The motor output torque is inversely proportional to the motor speed)
τ
Ｍ
=
60・P
０
(N·m)
(Equation 10.3-19)
2π・N
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.
△t
DEC
=
J
１
＋J
２
・η
Ｇ
・
2π・△ N
(s)
(Equation 10.3-20)
τ
Ｍ
－τ
Ｌ
・η
Ｇ
60
In this expression, both 
M
, and ΔN are generally negative values so that the load torque 
L
serves to assist the
deceleration operation. For a lift load, however, the load torque 
L
is a negative value in some modes. In this case,
the 
M
, and 
L
will take polarity opposite to each other and the 
L
will actuate to prevent the deceleration
operation of the lift.