Basic Documentation

Siemens Industry, Inc. Page 5 of 9
Document No. A6V10431169
11. The VFDs shall include a Quick Start-up wizard that leads the user through the typical HVAC required
parameters.
12. The VFD shall have the ability to automatically restart after an overcurrent, overvoltage, undervoltage,
or loss of input signal protective trip. The number of restart attempts, trial time, and time between
reset attempts shall be programmable.
13. The VFD shall be capable of starting into a rotating load (forward or reverse) and accelerate or
decelerate to speed command without tripping or component damage (flying start).
14. The VFD shall be capable of DC injection braking that can be employed to stop a freewheeling motor
prior to starting to avoid overvoltage nuisance tripping.
15. The VFD shall have the ability to be programmed to automatically extend the ramp-down time as
required to keep the drive from tripping on over-voltage caused by regeneration of power by the load
16. If the input sped reference (4 to 20 mA or 0 to 10V) is lost, the VFD shall give the user the option of
either (1) stopping and displaying a fault, (2) running at a programmable preset speed, (3) holding the
VFD speed based on the last good reference received, or (4) cause a warning to be issued, as
selected by the user. The drive shall be programmable to signal this condition via a keypad warning,
relay output and/or over the serial communication bus.
17. The VFD shall include two-zone PID controllers that allow the drive to maintain PID control from two
separate feedback signals. VFD shall include two PID setpoint sources, a sleep mode function, PID
set point boost and a feed forward function to improve process response.
18. Run permissive circuit shall be included for damper or valve control.
19. The customer terminal strip shall be isolated from the line and ground.
20. The drive shall employ current limit circuits to provide trip free operation:
a. The Slow Current Regulation limit circuit shall be adjustable to 150% (minimum) of the VFD's
normal duty current rating. This adjustment shall be made via the keypad, and shall be displayed
in actual amps, and not as percent of full load.
b. The Current Switch-off limit shall be fixed at 180% (minimum, instantaneous) of the VFD's normal
duty current rating.
21. The overload rating of the drive shall be 110% of its normal duty current rating for one minute in every
10 minutes.
22. The VFD shall have integrated DC bus chokes equivalent to 5% impedance. .
23. The VFD shall incorporate a Multi-Pump Controller Wizard capable of controlling up to four motors.
The VFD is connected to one motor which is the "regulating" motor connecting and disconnecting the
other motors to/from the mains, by means of contactors controlled with relays to maintain a given
setpoint. This function shall have an auto-change function for changing starting order of pumps which
allows for equal wear on all pumps.
24. The VFD shall be capable of sensing a loss of load (broken belt/no water in pump) or high current
mechanical sensing failure, and signal the loss of load condition. The drive shall be programmable to
signal this condition using a keypad warning, relay output and/or over the serial communications bus.
25. The VFD shall include a motor disconnect switch ride-through and is enabled or disabled through the
keypad. This feature allows the motor disconnect switch to be opened and closed without stopping or
tripping the drive.
H. All VFDs to have the following adjustments:
1. Three (3) programmable critical frequency lockout ranges to prevent the VFD from operating the load
continuously at an unstable speed.