Lenze TCF Series User Manual

Page 51

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Refer to the table herein for activation of the preset speeds using the TB-13 terminals .

SPEED # TB - 13A or 13D

TB - 13B

TB - 13C

1

CLOSED

OPEN

OPEN

2

OPEN

CLOSED

OPEN

3

OPEN

OPEN

CLOSED

4

CLOSED

CLOSED

OPEN

5

CLOSED

OPEN

CLOSED

6

OPEN

CLOSED

CLOSED

7

CLOSED

CLOSED

CLOSED

Preset Speed #6 and #7 can also be used as skip frequencies to restrict the drive from
operating at frequencies that cause vibration in the system . Refer to Parameter 38 .

NOTE
• When a TB-13 terminal is programmed for a function other than a preset

speed select, it is considered OPEN for the table above .

• PRESET SPEEDS #6 and #7 can still be used as preset speeds even if

they are also being used as skip frequencies .

P38

SKIP BANDWIDTH

The TCF drive has two skip frequencies that can be used to lock out critical frequencies that
cause mechanical resonance in the system . Once SKIP BANDWIDTH is set to a value other
than 0 .0 Hz, the skip frequencies are enabled . When the skip frequency function is enabled,
PRESET SPEED #6 and #7 are used as the skip frequencies . SKIP BANDWIDTH sets the
range above the skip frequencies that the drive will not operate within .

Example: The critical frequency is 23 Hz, and it is desired to skip a frequency range of 3 Hz
above and below the critical frequency (therefore the skip range is 20 to 26 Hz) . PRESET
SPEED #6 or #7 would be set to 20 Hz, and the SKIP BANDWIDTH would be set to 6 .0 Hz .

If the drive is running at a speed below the skip range, and it is given a speed command
that is within this range, the drive will accelerate to the start of the skip range (20 Hz in the
example) and run at that speed until the speed command is greater than or equal to the "top"
of the skip range . The drive will then accelerate through the skip range to the new speed .
Likewise, if the drive is running at a speed above the skip range, and it is given a speed
command that is within the skip range, the drive will decelerate to the "top" of the skip range
(26 Hz in the example) and run at that speed until the speed command is less than or equal
to the "bottom" of the skip range . The drive will then decelerate through the skip range to the
new speed .

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