5.8 L: Protection Functions
YASKAWA ELECTRIC SIEP C710616 38F YASKAWA AC Drive - L1000A Technical Manual 239
■ L8-38: Automatic Torque Boost Function
When the output current reaches a certain level the drive automatically reduces the carrier frequency to the level set in
L8-39. Because lowering the carrier frequency increases the overload tolerance, the drive is capable of creating
considerably more torque. When the output current falls, the carrier frequency switches back to the value set in C6-03.
Note: 1. Automatically lowering the carrier frequency increases motor noise.
2. Confirm drive capacity so that the maximum output current is less than the current limit.
Setting 0: Disabled
The carrier frequency is not automatically reduced.
Setting 3: Enabled
The torque capability is improved by reducing the carrier frequency when the output current exceeds a certain value.
■
L8-39: Reduced Carrier Frequency
Determines value the carrier frequency is reduced to by the torque boost function.
■
L8-55: Internal Braking Transistor Protection
Enables or disables protection for the internal braking transistor.
Setting 0: Disabled
Disable braking transistor protection when not using the internal braking transistor, including the following instances:
• When using a regen converter such as DC5.
• When using a regen unit such as RC5.
• When using external braking transistor options like CDBR units.
• When using the drive in common DC bus applications and the internal braking chopper is not installed.
Enabling L8-55 under such conditions can incorrectly trigger a braking transistor fault (rF).
Setting 1: Enabled
The following models come with a built-in braking transistor:
•CIMR-L20008 to 20115
•CIMR-L40005 to 40060
•CIMR-LU50003 to 50041
Enable L8-55 when connecting a braking resistor or a braking resistor unit to the drive built-in braking transistor.
Overload Tolerance for Internal Braking Transistor
Below, Figure 5.43 show the overload tolerance level for the drive’s built-in braking transistor.
No. Parameter Name Setting Range Default
L8-38 Automatic Torque Boost Function 0 or 3 0
No. Parameter Name Setting Range Default
L8-39 Reduced Carrier Frequency 1.0 to 15.0 kHz 3.0 kHz
No. Parameter Name Setting Range Default
L8-55 Internal Braking Transistor Protection 0 or 1 1
SIEP_C710616_38F_5_0.book 239 ページ 2015年11月9日 月曜日 午後3時36分