Hitachi SJ700D-004L, Instruction Manual

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Chapter 4 Explanation of Functions
4-23
(4) Internal DC braking (triggered only when the output frequency reaches a set frequency) (A051: 02)
You can also operate the internal DC braking function so that DC braking is applied to the motor when the inverter
output frequency falls to the DC braking frequency setting (A052) or below.
When the internal DC braking function is used in this mode, the external DC braking described in Item (2) and the
internal DC braking described in Item (3) cannot be used.
In this mode, DC braking operates only when the operation command signal is on (i.e., the start command is input).
The inverter starts DC braking when both the frequency set by the frequency command and the current output
frequency fall to the DC braking frequency setting (A052) or below. (See Example 7-a.)
When the frequency set by the frequency command increases to the "setting of 'A052' + 2 Hz" or more, the inverter
stops DC braking and restores its normal output. (See Example 7-a.)
If the frequency set by the frequency command is 0 Hz when the start command is input via an analog input terminal,
the inverter will start operation with DC braking because both the frequency set by the frequency command and
current output frequency are 0 Hz. (See Example 7-b.)
If the operation command signal (start command) is turned on when the frequency command specifies a frequency
larger than the DC braking frequency (A052), the inverter will start operation with the normal output.
(Example 7-a) (Example 7-b)
How the inverter returns to the normal output varies depending on the setting of the DC braking/edge or level
detection for [DB] input (A054).
(a) Edge mode (b) Level mode
ON
Operation
command
Frequency
command
Output
frequency
Operation
command
Frequency
command
Output
frequency
Operation
command
Frequency
command
Output
frequency
Operation
command
Frequency
command
Output
frequency
A052
ON
A052
A052
ON
A053
A052
ON