KEB COMBIVERT F5 MULTI Applications Manual page 353

Braking time DEC
Formula
K = 0,25 for motors up to
0,20 for motors 2,2 to
0,15 for motors 5,5 to 11 kW
0,08 for motors 15 to 45 kW
0,05 for motors
Cyclic duration factor (cdf)
© KEB Antriebstechnik, 2002
All Rights reserved
The braking time DEC is adjusted at the frequency inverter. If it is chosen too
small the KEB COMBIVERT switches off automatically and the error message
OP or OC appears. The approximate braking time can be determined according to
following formulae.
1. Braking time without braking resistor
(J
M
t =
Bmin
9,55 ï (K ï M
Valid range: n
(Field weakening range)
3. Peak braking power
P =
B
Condition:
J = mass moment of inertia motor
M
1,5 kW J = mass moment of inertia load
L
4 kW n = motor speed prior to deceleration
1
n = motor speed after deceleration
2
(standstill= 0 rpm)
> 45 kW n = rated motor speed
N
M = rated motor torque
N
M = braking torque (necessary)
B
M = load torque
L
t = braking time (necessary)
B
t = minimum braking time
Bmin
t = cycle time
Z
P = peak braking power
B
P = peak power of braking resistor
R
Cyclic duration factor for cycle time t
t
B
cdf =
t
Z
Name: Basis
KEB COMBIVERT F5
Project Planning
+ J ) ï (n - n )
L 1 2
+ M )
N L
> n
1 N
M ï n
B 1
9,55
P < P
B R
< 120 s
Z
ï 100 %
f
t
Z
2. Braking torque (necessary)
(J + J ) ï (n - n
M L 1
M =
B
9,55 ï t
B
Condition: M < 1.5 ï M
B
f < 70 Hz
4. Braking time with braking resistor
(J + J ) ï (n - n
M L 1 2
t * =
Bmin
(
9,55 ï Kï M + M
N
Valid range: n > n
1 N
P ï 9,55
R
Condition: < M
(n - n )
1 2
f < 70 Hz
P < P
B R
[kgm 2 ]
2
[kgm ]
[rpm]
[rpm]
[rpm]
[Nm]
[Nm]
[Nm]
[s]
[s]
[s]
[W]
[W]
Cyclic duration factor for cycle time t
t
B
cdf = ï 100 %
120 s
t
t
B
Date Chapter Section
10 1
04.05.04
)
2
- M
L
N
)
P ï 9,55
R
)
+
L
(n - n )
1 2
ï (1,5 -K)
N
10
> 120 s
Z
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