SJ700-2 Instruction Manual NT204DX - Hitachi America, Ltd.

Chapter 4 Explanation of Functions
(3) Internal DC braking (A051: 01)
You can apply DC braking to the motor even without entering braking signals via the DB terminal when the
inverter starts and stops. To use the internal DC braking function, specify "01" for the DC braking enable
(A051).
Use function "A057" to set the DC braking force for starting, and use function "A058" to specify the DC
braking time for starting, regardless of the braking mode selection (edge or level mode). (See examples
4-a and 4-b.)
Set the braking force for periods other than starting by using the DC braking force setting (A054).
Set the output frequency at which to start DC braking by using the DC braking frequency setting (A052).
When you set the DC braking wait time (A053), the inverter output will be shut off when the output
frequency reaches the setting of "A052" after the operation command (FW signal) is turned off, and the
motor will run freely for the delay time set by "A053". DC braking will be started after the delay (A053).
The internal DC braking operation to be performed when the operation command is switched from the stop
command to the start command varies depending on the braking mode (edge or level mode).
Edge mode: The DC braking time setting (A055) is given priority over operation commands, and the
inverter performs DC braking according to the setting of "A055". When the output frequency
reaches the setting of "A052" the inverter performs DC braking for the time set for "A055".
Even if the stop command is input during DC braking, DC braking continues until the time
set for "A055" elapses. (See examples 5-a and 6-a.)
Level mode: Operation commands are given priority over the DC braking time setting. The inverter
follows operation commands, regardless of the DC braking time setting (A055). If the start
command is input during DC braking, the inverter starts the normal motor operation,
regardless of the DC braking time setting (A055). (See examples 5-b and 6-b.)
(a) Edge mode
(b) Level mode
i) (Example 4-a) when the start command is input: i) (Example 4-b) when the start command is input:
FW
FW
Output
frequency
Output
frequency
A057
A057
A058
A058
ii) (Example 5-a) when the stop command is input:
FW
ii) (Example 5-b) when the stop command is input:
FW
Output
frequency
Free running
Output
frequency
Free running
A052
A053
A055
A052
A053
A055
ii) (Example 6-a) when the stop command is input:
FW
ii) (Example 6-b) when the stop command is input:
FW
Output
frequency
Output
frequency
A052
A055
A052
A055
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