Drive Bypass - Danfoss VLT HVAC Basic Drive Programming Manual

Parameters
NOTE
In the above, alarms are produced or ignored in accordance
with the selection in 24-09 FM Alarm Handling.
24-05 FM Preset Reference
3 3
Range:
0 Hz [-100 - 100 Hz] Enter the required preset reference/set
*
24-09 FM Alarm Handling
Option:
[1] Trip, Crit.Alarms
*
[2] Trip, All Alarms/
Test
NOTE
Warranty-affecting alarms. Certain alarms can affect the
lifetime of the frequency converter. Should one of these
ignored alarms occur whilst in Fire Mode, a log of the event
is stored in the Fire Mode Log.
Here the 10 latest events of warranty-affecting alarms, fire
mode activation and fire mode deactivation are stored.
NOTE
The setting in 14-20 Reset Mode is disregarded in case of Fire
Mode being active (see parameter group 24-0*, Fire Mode).
No:
4 Mains ph. Loss
7
8
9 Inverter overloaded
13
14
16
29 Power card temp
33
38
65 Ctrl. card temp
72
Function:
point as a percentage of the Fire Mode
Max Reference set in Hz.
Function:
In case of a critical alarm, the frequency
converter will trip and not auto-restart
(Manual Reset).
It is possible to test the operation of Fire
Mode, but all alarm states are activated
normally (Manual Reset).
Critical
Description
Alarms
DC over volt x
DC under volt x
Over current x
Earth fault x
Short circuit x
Inrush fault
Internal fault
MG.18.B1.02 - VLT
VLT HVAC Basic Drive Programming Guide

3.16.2 24-1* Drive Bypass

The frequency converter includes a feature, which can be
used to automatically activate an external electro-
mechanical bypass in case of the event of a Fire Mode Coast
(see 24-00 FM Function).
The bypass will switch the motor to operation direct on line.
The external bypass is activated by means of one of the
digital outputs or relays in the frequency converter, when
programmed in parameter group 5-3* or parameter group
5-4*.
NOTE
The Drive Bypass cannot be deactivated if in Fire Mode. It
can be deactivated only by either removing the Fire Mode
command signal or the power supply to the frequency
converter!
When the Drive Bypass function is activated, the display on
the LCP will show the status message Drive Bypass. This
message has a higher priority than the Fire Mode status
messages. When the automatic Drive Bypass function is
enabled, it will cut in the external bypass according to the
below sequence:
Operation
Alarm
Warranty
Affecting
Bypass
Delay
Alarms
Timer
P24-11
x
ON
Relay
"Bypass"
OFF
x
Status can be read in the Extended Status Word 2, bit
number 24.
x
x 24-10 Drive Bypass Function
x
Option:
x
[0] Disabled
*
[2] Enabled (Fire
Mode only)
®
is a registered Danfoss trademark
Alarm Auto Resets
Speed
Function:
This parameter determines, what circum-
stances will activate the Drive Bypass
Function:
The Bypass Function will operate at Trip at
Critical Alarms, Coast or Bypass Delay Timer
if the timer expires before reset attempts
have completed.
Auto Reset Disabled
On delay (P5-41)