Hitachi L700 SERIES Instruction Manual page 82

Chapter 4 Explanation of Functions
4.2.19 DC braking (DB) setting
The DC braking function allows you to apply DC braking to the
motor according to the load on the motor.
You can control DC braking in two ways: the external control
through signal input to intelligent input terminals and the internal
control to be performed automatically when the motor is started
and stopped.
Note that the motor cannot be stopped by DC braking if the load
on the motor produces a large moment of inertia.
Item
DC braking enable
DC braking
frequency setting
DC braking wait
time
DC braking force
during deceleration/
DC braking force for
starting
DC braking time for
deceleration
DC braking/edge or
level detection for
[DB] input
DC braking time for
starting
DC braking carrier
frequency setting
(NOTE) <>:applied for 90 to 160kW
(1) Carrier frequency for DC braking
Use the DC braking carrier frequency setting (A059) to specify the carrier frequency for DC braking.
But the raking power reduced is reduced when 3kHz (up to 75kW) or 5kHz (90-160kW) are set as
shown below. For detailed decreasing ratio, "DC braking limiter" is to be referred.
70
Maximum
60
braking
force (%)
50
40
30
20
10
0
3
DC braking carrier frequency(kHz)
DC braking force limiter(11-75kW)
Function code Data or range of data
A051
A052 0.00 to 60.00 (Hz)
A053 0.0 to 5.0 (s)
0. to 70. (%)
A054/A057
<0. to 50 (%)>
A055 0.0 to 60.0 (s)
A056
A058 0.0 to 60.0 (s)
0.5 to 12(kHz)
A059
<0.5 to 8 (kHz)>
(58)
(46)
(34)
(22)
(10)
5 7 9 11 12
00 Internal DC braking is disabled.
01 Internal DC braking is enabled.
Internal DC braking is enabled. (The braking
02
operates only with the set braking frequency.)
With internal DC braking enabled, DC braking is
started when the output frequency reaches the
set braking frequency.
The DC braking wait time specifies the delay in
starting DC braking after the set braking time has
elapsed or the DB terminal has been turned on.
"0" specifies the smallest force (zero current);
"100" specifies the largest force (rated current).
This setting is valid for the external DC braking in
edge mode or for the internal DC braking.
00 Edge mode (See examples 1-a to 6-a.)
01 Level mode (See examples 1-b to 6-b.)
This setting is valid for the internal DC braking.
DC braking is started when the motor-start
command is input.
Unit: kHz
70
Maximum
60
braking
force (%)
50
40
30
20
10
0
DC braking carrier frequency(kHz)
DC braking force limiter(90-160kW)
4 - 20
Related code
A051: DC braking enable
A052: DC braking frequency setting
A053: DC braking wait time
A054: DC braking force during deceleration
A055: DC braking time for deceleration
A056: DC braking/edge or level detection for
[DB] input
A057: DC braking force for starting
A058: DC braking time for starting
A059: DC braking carrier frequency setting
C001 to C008: Terminal [1] to [8] functions
Description
(50)
(25)
(10)
4 5 6 7 8
3