Mitsubishi Electric FR-A720-0.4K Instruction Manual page 515

2 Voltage reduction selection during stall prevention operation (Pr.154)
The setting values "10 and 11" are added for Pr.154 Voltage reduction selection during stall prevention operation.
Parameter
Number
154
Voltage reduction selection
V/F V/F V/F
during stall prevention
operation
Magnetic flux Magnetic flux Magnetic flux
(1) To further prevent a trip (Pr. 154)
 When Pr. 154 is set to "0, 10", the output voltage reduces during stall prevention operation. By making this
setting, an overcurrent trip becomes less likely to occur. Use this function when torque reduction does not pose
a problem.
 Set Pr.154 = "10, 11" when the overvoltage protective function (E.OV) activates during stall prevention
operation in an application with large load inertia. Note that turning OFF the start signal (STF/STR) or
varying the frequency signal during stall prevention operation may delay the acceleration/deceleration
start.
(2) Causes and corrective actions
Operation Panel
Indication
Name
Description
Check point
Corrective action
Operation Panel
Indication
Name
Description
Check point
Corrective action
Initial
Name
Value
E.OV1
Regenerative overvoltage trip during acceleration
If regenerative energy causes the inverter's internal main circuit DC voltage to reach or exceed the
specified value, the protective circuit is activated to stop the inverter output. The circuit may also be
activated by a surge voltage produced in the power supply system.
· Check for too slow acceleration. (e.g. during descending acceleration with lifting load)
· Check if Pr.22 Stall prevention operation level is set too low like the no-load current.
 Check if the stall prevention operation is frequently activated in an application with a large
load inertia.
· Decrease the acceleration time.
· Use the regeneration avoidance function (Pr. 882 to Pr. 886). (
Manual (Applied).)
· Set a value larger than the no load current in Pr. 22 Stall prevention operation level.
 Set Pr.154 Voltage reduction selection during stall prevention operation = "10 or 11". (
Chapter 4 of the Instruction Manual (Applied).)
E.OV2
Regenerative overvoltage trip during constant speed
If regenerative energy causes the inverter's internal main circuit DC voltage to reach or exceed the
specified value, the protective circuit is activated to stop the inverter output. The circuit may also be
activated by a surge voltage produced in the power supply system.
· Check for sudden load change.
· Check if Pr.22 Stall prevention operation level is set too low like the no-load current.
 Check if the stall prevention operation is frequently activated in an application with a large
load inertia.
· Keep load stable.
· Use the regeneration avoidance function (Pr. 882 to Pr. 886). (
Manual (Applied).)
· Use the brake unit or power regeneration common converter (FR-CV) as required.
· Set a value larger than the no load current in Pr. 22 Stall prevention operation level.
 Set Pr.154 Voltage reduction selection during stall prevention operation = "10 or 11". (
Chapter 4 of the Instruction Manual (Applied).)
Setting
Range
With voltage
0
reduction
Without voltage
1
reduction
1
With voltage
10
reduction
Without voltage
11
reduction
Magnetic flux Magnetic flux Magnetic flux
V/F V/F V/F
FR-PU04
FR-PU07
FR-PU04
FR-PU07
18/24
Description
You can select whether to use
output voltage reduction during
stall prevention operation or not.
Use these settings when the
overvoltage protective function
(E.OV) activates during stall
prevention operation in an
application with large load inertia.
OV During Acc
Refer to Chapter 4 of the Instruction
Stedy Spd OV
Refer to Chapter 4 of the Instruction
BCN-C22005-634
Refer to
Refer to