Rockwell Automation 20B PowerFlex 700 AC Drives Vector Control (v4.001 and up) - Manual (Page 111)

Rockwell Automation Publication 20B-UM002G-EN-P - July 2014 111
Application Notes Appendix C
External Brake Resistor
Figure 5 - External Brake Resistor Circuitry
Hand-Off-Auto (HOA) The Hand-Off-Auto feature (firmware revision 10.001 and later) adds a delay to
the Start input when 3-wire control is used. This helps to prevent a stop/start race
condition. A 50 ms delay is added after the stop input is closed and before the
start input is checked. To select this feature, choose “HOA Start” (70), in [Digital
Inx Sel], parameters 361…366 (see
page 63 ).
Lifting/Torque Proving The TorqProve™ feature of the PowerFlex 700 is intended for applications where
proper coordination between motor control and a mechanical brake is required.
Prior to releasing a mechanical brake, the drive will check motor output phase
continuity and verify proper motor control (torque proving). The drive will also
verify that the mechanical brake has control of the load prior to releasing drive
control (brake proving). After the drive sets the brake, motor movement is
monitored to ensure the brakes ability to hold the load. TorqProve can be
operated with an encoder or encoderless.
ATTENTION: The drive does not offer protection for externally mounted brake
resistors. A risk of fire exists if external braking resistors are not protected.
External resistor packages must be self-protected from over temperature or a
circuit equivalent to the one shown below must be supplied.
Power On
R (L1)
S (L2)
T (L3)
Power Source DB Resistor Thermostat
Power Off
M
M
(Input Contactor) M
Three-Phase
AC Input