en cannot accept the
possibility of a hum or, in extreme cases, a buzz. Further, in an AC valve,
anything that will prevent proper mating of the plunger pole faces, including
dirt and corrosion, can cause noisy operation. In addition, AC solenoids,
because of the in-rush current and fast cycling, can evidence higher heat
rise than would be experienced under steady-state conditions, another
problem in hospital/medical/ laboratory applications. The reactance on AC
solenoids increases progressively, reducing the current as the plunger
moves into its seated position. If the plunger is restricted, the temperature
will increase as the square of the current.
All of these inherent AC valve conditions have led us to provide many AC
valves with diode rectified coils, allowing the valve to run on DC power for
cooler and quieter operation in application where these are required.
Fortunately, semi-conductor diodes are considerably less expensive today
than in the past, and their use has not caused a significant cost increase
where DC operation is necessary.
Operating on DC, the valve plunger need not be seated on its stop in
order to prevent coil burnout, and the typical DC solenoid exhibits a longer
life because it is not subjected to the peak voltages produces by the more
broadly cycling AC current. The closed gap pull force is greater on DC than
AC for the same pole area. Normally the AC pull curve has a sharper bend at each peak or valley, while the DC curve is
consistently flatter.
Given the many superior properties of solenoid valves with diode rectified coils converting AC input power to DC
operation, and the increase in medical-oriented applications where these DC valve capabilities are desirable, we are able
to offer most basic solenoid valves with a diode rectified coil to meet specific user criteria. For applications which require
it, a 4-diode full wave bridge also is available.
Location of the rectified fly back diode array in DC
rectified solenoid valve coil is shown (cutaway). Most of
our valves can be so configured, including the Models 50,
20, and 30 (left to right) above, all specified with diode
rectified coils for the inherent low noise/low temperature
provided by DC operation. They are used primarily for low
noise/low temperature quiet locations such as hospitals
and laboratories.
Diode Rectified Solenoid Valve Coils
For Quiet Operation
SOLENOID VALVES . . . Coil Options
Peter Paul Electronics Co., Inc., offers water-resistant solenoid valves featuring a
fully encapsulated coil, for applications where exposure to moisture or even complete
submersion is necessary.
The Series 15 or 50 valves are intended for a wide range of outdoor uses including
HVACR, irrigation systems, off-road equipment, trucks, buses, trains or other vehicles
experiencing significant exposure to wet environments, including boat trailers,
controls, engine and bilge areas. The valves feature a liquid epoxy potted coil
assembly and a rugged housing covered with a baked-on epoxy/polyester finish rated
at 1000+ hours in a 5% salt spray test. The potting provides increased heat transfer
capabilities through elimination of trapped air pockets for a cooler running valve.
All internal parts are constructed of stainless steel and brass. Corrosion resistant
materials are used for exposed parts. The standard version operates on a 12 VDC,
single lead power connection. Dual power lead versions can be used for mounting on
non-conductive surfaces such as fiberglass, plastic or wood. Additional power options
are also available.
Peter Paul Water-resistant Valves
for Submerged Operations ®
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®
Encapsulated Diode Spade Coil For Series 15
Solenoid Valves
A full wave bridge can now be
ecapsulated into the coil assembly
Series 15 solenoid valves. By
embedding the required electronics in
the coil, a DC valve can be driven by
common AC voltages.
Each valves encapsulated coil
contains a diode circuit that converts
common 50/60 Hz voltage to DC.
Running the coil on DC eliminates the
in-rush current associated with AC
valves, thus limiting the excessive heat
build-up encountered with frequently
cycled valves. The use of DC coil
voltage also allows the use of an
elastomeric damper within the valve
itself. This damper reduces the audible
click which occurs on actuation as well
as increases the life of the valve, for a
wide range of hospital and laboratory
applications.
SOLENOID VALVES . . . Coil Options
These solenoid valves are factory-equipped with the required pin connectors
and as-specified leads and lead lengths to allow the installation of valves by
maintenance personnel without the need for on-site electrical engineers.
It is recognized that solenoid valves can be
configured with numerous coil options, voltages,
orifice sizes, pressure ratings, elastomers,
footprints, and more. In addition, there are a wide
range of attachments and add-ons such as splice
boxes, mounting brackets, manifolds, and more to
enhance the utility of the solenoid valve.
To provide even more value-added aspects to our
valves, these solenoid valves are offered with many
electrical connectors, allowing on-the-floor
maintenance staff personnel to disconnect and
switch solenoid valve connections without the need
for an electrical engineer. These electrical
connectors include male or female pins and
connectors, custom lead lengths, junction box
connectors, and other simple fasteners which can
be handled on the plant floor or in the field. Typical
electrical connectors include pin styles,
receptacles, housings, flag connectors, and two- or
three-pin flange connectors. While the add-on costs
of these pins and connectors are nominal, their
inclusion at the factory make the solenoid valves of
which they are a part installation-ready as received
by the user.
Electrical Connectors ®
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This time delay coil with built-in thermistor
(cutaway) is at the heart of the Peter Paul Series 30
solenoid valves employed on many oil burners.
Time delay coils with built-in thermistors have been developed for our
Series 30 solenoid valves. The thermistor circuit in the solenoid valve coil
delays the pick up of the valves plunger from 2 to 6 seconds. This allows
the solenoid to be certain of the required process parameters before media
flow commences.
A common example is the start-up sequence for an oil burner. It is vital
that a sensor in the furnaces electrical circuit sees that a flame has been
generated to continue the flow of fuel oil. If there is no flame, oil flow may
flood the burner, often requiring maintenance of an extended period of time
before a re-start can be initiated. When the call activates the burner, the
solenoid valves time delay function allows the pump and fan/motor to
reach operating speed before starting fuel flow.
Series 30 solenoid valves, UL recognized and CSA listed, are frequently
used in these boiler and furnace applications because of their economical
pricing and compact size.
Time Delay Coils Check Process
Before Media Flow
For many small AC motor applications including powered
hand tools, it has become quite common for the motors to be
configured to operate at one of two voltage levels,
typically 120/240 VAC-60 Hz OR 240/480 VAC-60 Hz.
Now for the Series 20, 50, 60 and 80, 2-, 3-, and 4-way
solenoid valves, we can provide dual voltage coils to allow the
solenoid valves to be wired for either of the applicable voltages,
reducing parts inventory and product installation / assembly at
the distributor, OEM, and end user locations.
For specific applications in which more than one voltage
might be encountered, the dual voltage solenoid valves are
identical to their single-voltage versions except for the
additional coil windings and leads.
Dual voltage, four-wire coil and completed dual voltage solenoid
valve (Series 20, left and Series 50, right) are used when two voltages
may be involved in a process, typically 120/240 VAC or 240/480 VAC.
Dual Voltage Solenoid Valve Coils
SOLENOID VALVES . . . Coil Options
Series 58 Super Sub-Miniature Coils
These coils were specifically designed for
small places. The Sub-Miniature coil mounts on
our existing Series 58 Bodies, ie Stainless Steel
Screw-In or 10-32 Ports and our standard plastic
bodies, Manifold Mount or 10-32 Ports. These
valves are ideal for micro electronic production
equipment and medical or chemical analytical
applications where space is limited. Also, can
easily be suited for any value added OEM
application, as shown with special brass fittings
and accessories. Consult factory for size,
pressure ratings, orifice sizes and power
requirements.