SC75 & SC105 Soft Start Valve
IS-SC105
2
Voltage
Coil No.
24VDC
2EV103
110VAC
2EV105
!
Function
The Soft Start valve is a 3-Port valve which supplies air in a
controlled reliable manner to pneumatic systems and has the
quick exhaust features of a dump valve. This valve replaces
conventional main valves.
The Soft Start valve operates much like a standard 3-Way
valve. When the valve is installed Port 2 is connected to Port
3 (downstream system is exhausted to atmosphere). When a
signal is received at the pilot operator, the connection between
Port 2 and 3 is closed. At the same time, supply air from Port 1 is
connected to Port 2 through the adjustable throttle, (Adjustment
Needle).
When the downstream pressure reaches a specific point, the
main poppet opens and permits full air flow through the valve.
The table shows the relationship between the inlet pressure and
the downstream pressure at which the main valve opens.
When the pilot signal is removed, the valve returns to its initial
position and the downstream air is dumped rapidly through
Port 3.
Port Connections
1. Connect inlet air supply to Port 1.
2. Connect mufflers (or plumb exhaust) from Port 3.
3. Connect cylinder Port 2 to cylinder or other system devices to
be supplied air.
4. Signal Connection - Soft Start valves may be remotely
controlled electrically.
a. For solenoid pilot operated valves, see the instructions
under “WIRING INSTRUCTIONS.”
Wiring Instructions
!
CAUTION: An interruption of 10 milliseconds or greater
to the power supplied to the solenoid of a solenoid
operated valve may cause the valve to shift. Provision
must be made to prevent power interruption of this
duration to avoid unintended, potentially hazardous,
consequences.
NOTE: In addition to the following instructions, follow all requirements for
local and national electrical codes.
Attach an electrical cable with connector (that conforms to the
DIN 43650, Form B pattern) to the terminals of the solenoid. Do
not attach or remove the connectors until power is off.
Electrical Connection
Valves with 3-Pin male terminals should have power connected
to the parallel terminals. Ground should be connected to the
perpendicular terminal. Use only connectors that comply with
DIN 43650, Form B (11 mm blade spacing).
Override Operation
The flush non-locking manual override is located on the body
of the solenoid pilot. To operate the override, push in on the
override until the solenoid pilot actuates. The solenoid pilot will
remain actuated until the override is released. When released,
the solenoid pilot de-actuates.
Adjustment
The filling speed and pressurization of downstream circuit
is accomplished by a Needle Valve located in the Cover
(See Figure 1). Adjustment is performed using a standard flat
blade screwdriver as indicated in Figure 1. Adjustments can be
made by performing start-up test and adjusting the Needle Valve
from zero to a maximum of 4 turns open until desired equipment
speed is reached.
!
Caution: Do not turn needle valve more than 4 turns out
from closed position as it is a pressure circuit and could
blow out with force.
The adjustment of the initial airflow rate into the downstream
side of the soft-start valve is done with the Needle Valve. Turning
Needle Valve counterclockwise will decrease amount of time to fill
downstream circuit. Turning Needle Valve clockwise will increase
amount of time to fill downstream circuit.
Once the desired start-up speed of the downstream circuit has
been reached, the adjustment area can be blocked off to prevent
tampering by inserting the Lockout Pin provided in the package.
Any further adjustments will require the removal of the Lockout
Pin as shown in Figure 2.
Solenoid Replacement
To replace the solenoid, remove the solenoid nut and pull
solenoid off and replace with the correct voltage solenoid.
Replace solenoid nut and tighten finger tight. See Figure 3.
Service
Caution: Disconnect or shut off air supply and exhaust
pressure before servicing unit.
Figure 1
Adjustment
Figure 2
Lockout Pin Removal
Inlet
Downstream
Pressure
Pressure for
Full Flow
75 PSIG
50 PSIG
100 PSIG
55 PSIG
125 PSIG
60 PSIG
150 PSIG
65 PSIG
Start-Up Of Soft Start
Flow
Regulating
Needle
Valve
Pilot Air Vent
Pressure
Begins to
Ramp Up
Solenoid
Energized
100 PSIG
IN
OUT
Full Open
Full Flow
at 65% of
Inlet Pressure
Solenoid
Energized
100 PSIG
IN
OUT
Exhaust and Closed
Pressure
Dumps to
Zero
Solenoid
De-Energized
100 PSIG
IN
OUT
