AC Tech MC1000 series, Installation And Operation Manual

Page: 52 / 88

50
PRESET SPEED ACTIVATION
SPEED #
SPEED # SPEED #
SPEED # TB - 13A
TB - 13A TB - 13A
TB - 13A TB - 13B
TB - 13B TB - 13B
TB - 13B TB - 13C
TB - 13C TB - 13C
TB - 13C
1 CLOSED OPEN OPEN
2 OPEN CLOSED OPEN
3 OPEN OPEN CLOSED
CLOSED CLOSED OPEN
4 CLOSED OPEN CLOSED
OPEN CLOSED CLOSED
The preset speeds can only be set to values that are within the operating range
defined by the minimum and maximum frequency (see Parameters: 10 - MIN
FREQ, and 11 - MAX FREQ).
The following table shows how each preset speed is selected using the TB-13
terminals. The terms OPEN and CLOSED refer to the state of the TB-13 terminal
relative to TB-2.
NOTE: SPEED #4 is selected if any two of the three TB-13 terminals are closed
to TB-2.
5,6 SKIP #1 & #2 (SKIP SPEED #1 & #2)
7 BAND WID (SKIP BANDWIDTH)
T
hese parameters are used to prevent the drive from operating continuously at
critical speeds, or frequencies, that cause excessive mechanical vibration of the
driven equipment. The SKIP SPEEDS (Parameters 5 and 6) and the SKIP
BANDWIDTH (Parameter 7) are used to define up to two speed avoidance
ranges. The SKIP SPEED settings define the starting point of the speed range that
is to be avoided, and the SKIP BANDWIDTH setting defines how far the speed
range extends beyond SKIP SPEED. Setting the SKIP SPEEDS to .00 Hz disables
this function.
Example: The critical frequency is 21 Hz, and a bandwidth of 2 Hz is desired.
Therefore, set SKIP #1 to 20 Hz and set SKIP BANDWIDTH to 2 Hz. This
results in a speed range from 20 Hz to 22 Hz that the drive will not operate within
continuously. If the drive were operating at 25 Hz and then commanded to
operate at a speed within the range of avoidance, the drive would decelerate to 22
Hz and remain at that frequency until commanded to 20 Hz or below. The drive
would then decelerate through the range of avoidance to the new frequency.
Likewise, if the drive were operating at 18 Hz, and then commanded to operate at
a speed within the range of avoidance, the drive would accelerate to 20 Hz and
remain at that frequency until commanded to a speed of 22 Hz or above. The drive
would then accelerate through the range of avoidance to the new frequency.