Peter electronic 2C000.23020, Инструкции по сборке и пусконаладке

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14 VBMS ....
13. Dimensioning rules
Note! All data sheets and commissioning instructions are avaialble on our
homepage at
www.peter-electronic.com .
13.1 Dimensioning of braking device
For most applications, it is relatively easy to select a suitable braking device.
In most cases, an acceptable braking torque is achieved, if. during braking, the motor is
connected in
Y (star) and the braking current is 2 times as high as the rated motor current. If,
during braking, the motor winding can only be connected in Δ (delta), the braking current has to
be at least 2.5 times as high as the rated motor current in order to achieve a sufficiently high
braking torque.
If special applications require more precise calculations, the following formula can be used.
Calculating the braking current (I
B
))
Table 1
I
B
= Braking current in A
f
B
= Braking factor acc. to table 1
t
B
= Braking time required (in s)
I
N
= Nominal/rated motor current (in A)
t
A
= Time until nominal speed is reached
(in the case of motors with star-delta start - approx.
switch-over time)
Values usual for t
A
:
Conveyor belt::20s, Pump: 8s, Power crusher: 30s,
Compressor: 10s, Fan: 20s, Circular saw: 10s
N
B
A
B B
I
t
t
f I
⋅ ⋅ ⋅
= 2.6
Connection of motor winding
at nominal operation
during braking
b
a
f
B
b
a
f
B
= 3
b
a
f
B
= 1.7