Load Slips At Start; Load Slips At Stop; Slipping Occurs During Extremely Fast Inching; Load Falls When Brake Is Applied - YASKAWA CR700 Technical Manual

3.11 Problems that Can Frequently Occur during Setup and Possible Solutions

Load Slips at Start

◆
Causes
The setting values of S1-05 [Brake Release Current (FWD)], S1-06 [Brake
Release Current (REV)], S1-07 [Brake Release Torque (FWD)], and S1-08
[Brake Release Torque (REV)] are too low.
The V/f setting is too low.
The setting value of C4-02 [Torque Compensation Delay Time] is too high
while using Open Loop Vector Control.
The setting value of S1-09 [Torque Compensation (FWD)] (the amount of
torque forcing) is too low while using Open Loop Vector Control, Closed
Loop Vector Control, or Advanced Open Loop Vector Control.
The output current is more than 125% of the rated current while using
Closed Loop Vector Control or Advanced Open Loop Vector Control.
The output current is more than 125% of the rated current while using Open
Loop Vector Control.
The output current is more than 125% of the rated current while using V/f
Control.
Note:
Refer to "Magnetic Flux Compensation (Start-up Current Suppression)" on page

Load Slips at Stop

◆
Causes
The setting value of S1-05 [Brake Release Current (FWD)] is too low while
using V/f control or OLV control.
The setting value of b2-04 [DC Inject Braking Time at Stop] is too low while
using Closed Loop Vector Control or Advanced Open Loop Vector Control.
Brake hold settings are not correct.

Slipping Occurs During Extremely Fast Inching

◆
Causes
Drive operation and brake operation do not keep up with the inching
operation.

Load Falls When Brake Is Applied

◆
Causes
The open/close timing of the brake is incorrect.
The DC injection braking is insufficient.

Excessive Current Occurs at Start

◆
Causes
The brake sequence is not adjusted.
The motor flux build up is not enough while using Closed Loop Vector
Control or Advanced Open Loop Vector Control.
Torque settings are too low while using Open Loop Vector Control, Closed
Loop Vector Control, or Advanced Open Loop Vector Control.
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Possible Solutions
Increase the setting values of S1-05 to S1-08.
Increase the V/f setting.
Set C4-02 ≒ 20 [20 ms].
Set S1-09 ≒ 50 to 80 [50% to 80%].
Do these procedures to solve problems with starting up magnetic flux.
• Set b2-03 = 0.2 to 0.3 [DC Inject Braking Time at Start = 0.2 s to 0.3 s].
• Set d6-03 = 1 [Field Forcing Selection = Enabled] and d6-06 = 200 to 400 [Field Forcing
Limit = 200% to 400%].
• Do the initial excitation process.
Do these procedures to solve problems with starting up magnetic flux.
• Set b2-03 = 0.2 to 0.3 [DC Inject Braking Time at Start = 0.2 s to 0.3 s].
• Set b2-08 = 100 to 200 [Magnetic Flux Compensation Value = 100% to 200%].
• Increase the setting value of E1-08 [Mid Point A Voltage] to around 20 V maximum (40 V for
400 V class drive).
Do these procedures to solve problems with starting up magnetic flux.
• Set b2-03 = 0.2 to 0.3 [DC Inject Braking Time at Start = 0.2 s to 0.3 s].
• Increase the setting value of E1-08 [Mid Point A Voltage] to around 20 V maximum (40 V for
400 V class drive).
236 to solve problems in flux build up.
Possible Solutions
Increase the setting value of S1-15.
Set b2-04 > 0.50.
Increase the setting values of S1-12 [Brake Hold Frequency (FWD)] and S1-13 [Brake Hold
Frequency (REV)].
Possible Solutions
Increase the setting value of S2-01 [Run Cmd Minimum On Time (FWD)] and S2-02 [Run Cmd
Minimum On Time (REV)].
Possible Solutions
• Increase the value set in S1-14 [Slip Prevention Frequency].
• Increase the time set in S1-15 [Slip Prevention Time].
Increase the value set in b2-02 [DC Injection Braking Current].
Possible Solutions
• Decrease the setting values of S1-01 and S1-02 [Brake Release Frequency].
• Decrease the setting value of S1-03 [Brake Delay Frequency].
• Set S1-04 [Brake Delay Time] to align with the machine.
• Set d6-03 = 1 [Field Forcing Selection = Enabled] and d6-06 ≒ 200 to 400 [Field Forcing
Limit ≒ 200% to 400%].
• Do the initial excitation process.
• Set L7-01 to L7-04 ≒ 150 [Torque Limit ≒ 150%].
• Set S1-07 ≒ 70 to 80 [Brake Release Torque (FWD) ≒ 70% to 80%].
YASKAWA SIEPC71061723A YASKAWA AC Drive CR700 Technical Manual