Toshiba 48-1250 A User Manual
TOSHIBA- 17
TX Series
48 - 1250A
The current limit must be set high enough to allow the motor to
reach full speed. The factory setting of 350% is a good starting
point. Do not set the current limit too low on variable starting
loads. This could cause the motor to stall and eventually
cause the overload protection to trip.
reach full speed. The factory setting of 350% is a good starting
point. Do not set the current limit too low on variable starting
loads. This could cause the motor to stall and eventually
cause the overload protection to trip.
3.4 Deceleration Adjustments (Pump Control)
Decel extends the stopping time on loads that would otherwise stop
too quickly if allowed to coast to stop. Decel control provides smooth
deceleration until the load comes to a stop. Three adjustments
optimize the deceleration curve to meet the most demanding require-
ments. Try factory settings before adjusting.
too quickly if allowed to coast to stop. Decel control provides smooth
deceleration until the load comes to a stop. Three adjustments
optimize the deceleration curve to meet the most demanding require-
ments. Try factory settings before adjusting.
Deceleration Applications
The unit is shipped from the factory with the decel feature
disabled. Apply power and adjust the soft start before enabling or
modifying the deceleration adjustments. Both acceleration and deceleration
adjustments should be made under normal load conditions.
The unit is shipped from the factory with the decel feature
disabled. Apply power and adjust the soft start before enabling or
modifying the deceleration adjustments. Both acceleration and deceleration
adjustments should be made under normal load conditions.
The deceleration feature provides a slow decrease in the output voltage,
accomplishing a gentle decrease in motor torque during the stopping mode.
This is the OPPOSITE OF BRAKING in that it will take longer to
come to a stop than if the starter were just turned off. The primary use
of this function is to reduce the sudden changes in pressure that are
associated with “Water Hammer” and slamming of check valves with
centrifugal pumps. Decel control in pump applications is often referred
to as Pump Control.
accomplishing a gentle decrease in motor torque during the stopping mode.
This is the OPPOSITE OF BRAKING in that it will take longer to
come to a stop than if the starter were just turned off. The primary use
of this function is to reduce the sudden changes in pressure that are
associated with “Water Hammer” and slamming of check valves with
centrifugal pumps. Decel control in pump applications is often referred
to as Pump Control.
In a pump system, liquid is being pushed uphill. The force exerted by
gravity on the column of liquid as it goes up hill is called the “Head
Pressure” in the system. The pump is sized to provide enough Output
Pressure to overcome the Head Pressure and move the fluid up the
pipe. When the pump is turned off, the Output Pressure rapidly drops
to zero and the Head Pressure takes over to send the fluid back down
the hill. A “Check Valve” is used somewhere in the system to prevent
this (if necessary) by only allowing the liquid to flow in one direction.
The kinetic energy in that moving fluid is suddenly trapped when the
valve slams closed. Since fluids can’t compress, that energy is
transformed into a “Shock Wave” that travels through the piping
system looking for an outlet in which it dissipates. The sound of that
shock wave is referred to as “Water Hammer”. The energy in that
shock wave can be extremely damaging to pipes, fittings, flanges,
seals and mounting systems.
By using the Soft Stop/Deceleration feature of the TX, the pump output
torque is gradually and gently reduced, which slowly reduces the
pressure in the pipe. When the Output Pressure is just slightly lower
than the Head Pressure, the flow slowly reverses and closes the
Check Valve. By this time there is very little energy left in the moving
fluid and the Shock Wave is avoided. When the output voltage to the
motor is low enough to no longer be needed, the TX will end the Decel
cycle and turn itself off.
gravity on the column of liquid as it goes up hill is called the “Head
Pressure” in the system. The pump is sized to provide enough Output
Pressure to overcome the Head Pressure and move the fluid up the
pipe. When the pump is turned off, the Output Pressure rapidly drops
to zero and the Head Pressure takes over to send the fluid back down
the hill. A “Check Valve” is used somewhere in the system to prevent
this (if necessary) by only allowing the liquid to flow in one direction.
The kinetic energy in that moving fluid is suddenly trapped when the
valve slams closed. Since fluids can’t compress, that energy is
transformed into a “Shock Wave” that travels through the piping
system looking for an outlet in which it dissipates. The sound of that
shock wave is referred to as “Water Hammer”. The energy in that
shock wave can be extremely damaging to pipes, fittings, flanges,
seals and mounting systems.
By using the Soft Stop/Deceleration feature of the TX, the pump output
torque is gradually and gently reduced, which slowly reduces the
pressure in the pipe. When the Output Pressure is just slightly lower
than the Head Pressure, the flow slowly reverses and closes the
Check Valve. By this time there is very little energy left in the moving
fluid and the Shock Wave is avoided. When the output voltage to the
motor is low enough to no longer be needed, the TX will end the Decel
cycle and turn itself off.