Fairford Electronics QFE Series, Руководство пользователя

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page 5-15
Programming
QFE
FD8420 issue02_F
Current Limit
- This is the level of load current at which the unit stops
ramping up the voltage applied to the load, and prevents the ramp from continuing within a
time limit. At the end of the time limit (
Limit Time Out
, P31, see section 5.3.5 ) the unit will
either stop or continue depending on the value of
C/L Time Out
in the
Current
menu
(section 5.3.5 ). The default for this parameter is 3.5
×
Full Load Current.
Notes: 1. The actual current drawn by the load may exceed the Current Limit Level slightly
as the unit manages the current limit through control of the delay angle. 2. Current Limit is
only active during starting.
Power On Parameters
- This recalls the values from the last permanently saved
parameter set and loads them into the current configuration.
Protection
- This sets the trip modes which are available to the user
and also enables the user to turn on and off the Optimising Function. The available protection
modes are;
FULL
: all trips enabled, optimising function turned off;
FULL + OPTIMISE
: all trips enabled with optimising function turned on;
START + BYPASS
: all trips enabled during start and trips 4 -10 (see section
5.3.11 ) turned off during bypass;
PHASE LOSS ONLY
: trips 4 -10 are turned off, all others enabled.
5.3.4 The Advanced Menu.
The Advanced Menu holds parameters that only need to be changed to solve specific sets of
circumstances. The list that follows briefly explains what each menu item does.
Current
- Provides access to the
Current
(as in Amps) submenu.
Optimising Rate
- This parameter is an arbitrary number which dictates the
speed at which the unit will phase back the firing angle during optimising. The smaller the
number the faster the unit will reach it’s final optimising voltage. Some unstable loads benefit
from a slower optimising rate ( which equates to a larger
Optimising Rate
(number)), for
example reciprocating compressors and piston pumps which can experience very quick
changes in load. The default for this parameter is set to five (5).
Kick Start
- This menu item turns the Kick Start function
On
or
Off
.
The Kick Start applies a short-lived voltage kick at the beginning of the start ramp to dislodge
‘sticky’ loads. This is turned
Off
by default.
Kick Pedestal
- This parameter sets the voltage level for the Kick, as a
percentage of U
MAX
.
The default value is 75%.
Kick Time
- This parameter sets the duration of the Kick in supply
frequency cycles. I.e., UK supply frequency is 50Hz, so one cycle takes 20ms to pass, so
the default Kick Time of 25 cycles equates to 500ms.
Dwell Time
- This parameter sets the time given for a load to settle
down after the unit has reached Top of Ramp and before the unit enters Optimising mode (if
set).
Low Volts Stop
- This menu item turns
On
or
Off
the
Low Voltage Stop
function. When
On
this allows soft stop pedestals of less than 40% to be set. Soft stop
pedestals of 40% and less can be set with the
Low Volts Stop
set to
Off
, but they will be
treated by the unit as a 40% soft stop pedestal. By default this menu item is turned
Off
.
Contactor Delay
- This parameter sets the length of the delay between the
Relay K1 closing ( which brings in the main contactor in the standard wiring configuration,
see Electrical Installation), and the moment the unit starts conduction (see Figure
5.3.4 ).
This is to allow any bounce in the main contactor to settle down before the unit starts firing,
thus preventing nuisance tripping. By default this parameter is set to 160mS.