Brake Sequence Function (Pr. 278 To Pr. 285, Pr. 292) - Mitsubishi Electric FR-A720-0.4K Instruction Manual

4.14.5 Brake sequence function (Pr. 278 to Pr. 285, Pr. 292)

This function is used to output from the inverter the mechanical brake operation timing signal in vertical lift and
other applications.
This function prevents the load from dropping with gravity at a start due to the operation timing error of the
mechanical brake or an overcurrent alarm from occurring at a stop, ensuring secure operation.
Parameter
Name
Number
278 Brake opening frequency
279 Brake opening current
Brake opening current
280
detection time
281 Brake operation time at start
282 Brake operation frequency
283 Brake operation time at stop
Deceleration detection
284
function selection
Overspeed detection
285
frequency
*1
Automatic acceleration/
292
deceleration
*1 When exercising vector control with the FR-A7AP/FR-A7AL (option), this parameter changes to excessive speed deviation detection frequency
(For details, refer to page 117)
<Connection diagram>
Sink logic
Pr.184 = 15
Pr.190 = 20
MCCB
Power
supply
Start signal
Multi-speed signal
Brake opening completion signal
CAUTION
⋅ When brake sequence mode is selected, automatic restart after instantaneous power failure is invalid.
⋅ When using this function, set the acceleration time to 1s or longer.
⋅ Changing the terminal assignment using Pr. 178 to Pr. 189 (input terminal function selection) or Pr. 190 to Pr. 196 (output terminal
function selection) may affect the other functions. Set parameters after confirming the function of each terminal.
Initial
Value
3Hz
130%
0.3s
0.3s
6Hz
0.3s
0
9999
0
MC
R/L1 U
S/L2 V
T/L3 W
STF
RH
*3
*2
RUN(BOF)
AU(BRI) *
1
(BRI)
SD SE
Motor brake and stop operation
Magnetic flux Magnetic flux Magnetic flux Sensorless
Setting
Range
Set to the rated slip frequency of the motor + about 1.0Hz.
0 to 30Hz
This parameter may be only set if Pr. 278 ≤ Pr. 282.
Generally, set this parameter to about 50 to 90%. If the setting
0 to 220% is too low, the load is liable to drop due to gravity at start.
Suppose that the rated inverter current is 100%.
0 to 2s Generally, set this parameter to about 0.1 to 0.3s.
Set the mechanical delay time until the brake is loosened.
0 to 5s Set the mechanical delay time until the brake is loosened +
about 0.1 to 0.2s when Pr. 292 = "8".
Set the frequency to activate the mechanical brake by turning
OFF the brake opening request signal (BOF). Generally, set
0 to 30Hz
this parameter to the Pr. 278 setting + 3 to 4Hz.
Setting is enabled only when Pr. 282
Set the mechanical delay time until the brake is closed + 0.1s
when Pr. 292=7.
0 to 5s
Set the mechanical delay time until the brake is closed + 0.2
to 0.3s when Pr. 292 = 8.
0 Deceleration is not detected.
If deceleration is not normal during deceleration operation,
1
the inverter fault is provided.
If (detected frequency) - (output frequency) ≥ Pr. 285 during
0 to 30Hz encoder feedback control, the inverter fault (E.MB1) is
provided.
9999 Overspeed is not detected.
0 Normal operation mode
1, 11 Shortest acceleration/deceleration mode (Refer to page 180)
3 Optimum acceleration/deceleration mode (Refer to page 181)
5, 6 Elevator mode 1, 2 (Refer to page 163)
7 Brake sequence mode 1
8 Brake sequence mode 2
Mechanical
brake
Motor
24VDC
MC
Brake opening request
signal (BOF)
Sensorless Sensorless Vector Vector Vector
Description
≥
Pr. 278.
*1 The input signal terminal used differs
according to the Pr. 178 to Pr. 189
settings.
*2 The output signal terminal used differs
according to the Pr. 190 to Pr. 196
settings.
*3 The current should be within the
permissible current of transistor in the
inverter. (24V 0.1ADC)
4
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