Rockwell Automation 20B PowerFlex 70, PowerFlex 700 Reference Manual - Manual (Page 106)

Fuses and Circuit Breakers
106 Rockwell Automation Publication PFLEX-RM001H-EN-P - June 2013
Since the motor is “picked up “smoothly at its rotating speed and ramped to the
proper speed, little or no mechanical stress is present.
Configuration
Flying Start is activated by setting the [Flying Start En] parameter to “Enable”
The gain can be adjusted to increase responsiveness. Increasing the value in
[Flying StartGain] increases the responsiveness of the Flaying Start Feature
Application Example
In some applications, such as large fans, wind or drafts may rotate the fan in the
reverse direction when the drive is stopped. If the drive were started in the normal
manner, its output would begin at zero Hz, acting as a brake to bring the reverse
rotating fan to a stop and then accelerating it in the correct direction.
This operation can be very hard on the mechanics of the system including fans,
belts and other coupling devices.
Cooling Tower Fans
Draft/wind blows idle fans in reverse direction. Restart at zero damages fans,
breaks belts. Flying start alleviates the problem
Fuses and Circuit Breakers
Refer to the Powerflex 70 Technical Data (publication 20A-TD001 ) or
PowerFlex 700 Technical Data (publication 20B-TD001 ) for fuse information.
169 [Flying Start En]
Enables/disables the function which
reconnects to a spinning motor at actual
RPM when a start command is issued.
Default:
Options:
0
0
1
“Disabled”
“Disabled”
“Enabled”
170
Re
st
ar
t M
od
es 170 [Flying StartGain]
Sets the response of the flying start
function.
Default:
Min/Max:
Display:
4000
20/32767
1
169