Toshiba 48-1250 A Manual Do Utilizador

either VOLTAGE or CURRENT.

• Initial Torque  (Initial Voltage #1 or Initial

Current #1):  Sets the initial start point of either
the Voltage Ramp or the Current Ramp.  Every
load requires some amount of torque to start from
a standstill.  It is inefficient to begin ramping the
motor from zero every time, since between zero
and the WK2 break-away torque level, no work is
being performed.  The initial torque level should
be set to provide enough torque to start rotating
the  motor shaft, enabling a soft start and
preventing torque shock damage.  Setting this
start point too high will not damage the starter,
but may reduce or eliminate the soft start effect.

• Ramp Time #1:  Sets the maximum allowable

time for ramping the initial voltage or current
(torque) setting to either of the following:
1) the Current Limit setting when the motor is still
accelerating, or
2) full output voltage if the Current Limit is set to
maximum.
Increasing the ramp time softens the start
process by gradually increasing the voltage or
current.  Ideally, the ramp time should be set for
the longest amount of time the application will
allow (without stalling the motor).  Some
applications require a short ramp time due to the
mechanics of the system.  (i.e., centrifugal
pumps, because pump problems can occur due
to insufficient torque).

• Current Limit:  Sets the maximum motor

current the starter will allow during Ramping.  As
the motor begins to ramp, the Current Limit
feature sets a ceiling at which the current draw
is held.  Current Limit remains in effect until the
following occurs:
1) the motor reaches full speed (detected by the
At-Speed detection circuit) or
2) the Overload Protection trips on Motor Thermal
Overload.
Once the motor reaches full speed, the Current
Limit feature becomes inactive.

In the Voltage Ramp Profile, the voltage output is
increased until it reaches the Current Limit. Ramp
time is the maximum amount of time it takes for
the voltage to increase until the Current Limit
setting takes over.  With some load conditions,
the Current Limit is reached before the Ramp
Time expires.

The Current Ramp profile varies the output
voltage to provide a linear increase in current up
to the Maximum Current setpoint value.  A closed
loop feedback of motor current maintains the
Current Ramp profile.

Start Ramp 2:  The same options and screen
setups as Start Ramp 1.  Note: CUSTOM
ACCEL CURVE overrides the voltage or current
start in Ramps 1 and 2 when selected to be the
start control mode.

Kick Start:  Used as an initial energy burst in
applications with high friction loads.

• Kick Start Voltage:  The initial voltage (as a

percent of full voltage value) that is needed to
start the motor (i.e. Breakaway or Initial Torque).

• Kick Start Time:  The time the initial torque

boost is applied.

Deceleration:  Allows the motor to gradually
come to a soft stop.

• Start Deceleration Voltage:  The first part of

the deceleration ramp.  The TX initially drops to
this voltage level upon receiving a STOP
command.  (Represented as a percent of
voltage value.)

• Stop Deceleration Voltage:  The drop-off point

of the deceleration ramp. (Percent of voltage
value.)

• Deceleration Time:  Decel ramp time.

Timed Output:  Used with an AUX relay.  When
enabled, and upon a start command, it energizes
the assigned relay for the programmed time.  At
the end of the programmed time the relay  de-
energizes.  See Setpoint Page 4.

Run Delay Time:  Used with an AUX3 relay.
When enabled, and upon a start command, it
waits until the programmed time has expired.
The relay energizes and remains so until a stop
command is received.  It de-energizes upon
receiving a stop command.  See Setpoint Page
4.

At Speed Delay Time:  Used with an AUX4 relay,
it waits until after the motor reaches the end of
ramp and the programmed delay time has
expired.  The relay energizes until a stop
command has been received. See Setpoint Page
4.