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324 Consult “Precautions” page 327 before use, installation or service of MAC Valves.. Technical Info MAC’s PATENDED LATCHING SOLENOID – Eliminates one Solenoid, Simplifies Wiring, Reduces Package Size MAC’s latching sol…

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Consult “Precautions” page 327 before use, installation or service of MAC Valves..

Section 7

Supplemental technical information

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Consult “Precautions” page 327 before use, installation or service of MAC Valves..

Technical Info

MAC’s PATENDED LATCHING SOLENOID – Eliminates one Solenoid, Simplifies Wiring, Reduces Package Size

MAC’s latching solenoid technology provides the function of a double solenoid operated valve utilizing only one solenoid.

Typical 2 position direct operated double solenoid valves use two solenoids with spool/bore technology. When the power is removed

from either solenoid, the spool position and valve function is maintained.

With direct acting solenoid valves, poppets with their inherent short strokes are not typically used as they cannot maintain sealing

position when both solenoids are deenergized. As a consequence, longer stroking spool type solenoid valves are used which results in

lower shifting forces. MAC’s latching solenoid technology eliminates the sealing issue with poppets when no electrical signal is

applied, by maintaining solenoid force, ensuring adequate sealing, while using short stroking poppets resulting in high shifting forces.

MAC’s latching solenoid only requires one solenoid and correspondingly one plug-in and one conduit wireway verus two for

conventional double solenoid valve, saving space, weight and cost. An added benefit of a latching solenoid valve when mounted on

a circuit bar is the additional option of side cylinder ports.

HOW IT WORKS

Unlike a spool and bore valve, a poppet valve requires that a force be continuously applied to either end of the poppet to ensure that proper sealing occurs. If

another solenoid was simply added to the valve to create a double solenoid valve, power would need to be constantly applied to either solenoid for the valve to

function properly (see Figure 1). If the poppet valve is converted to a spool and bore type valve design, the longer stroke of the spool and solenoid would result

in lower net shifting forces (see Figure 2), compromising the valves shifting reliability.

The latching solenoid overcomes these problems by introducing a powerful

permanent magnet armature assembly which magnetically latches itself to

the pole piece and in turn keeps the poppet sealed against the conical

seats when the power is removed from the solenoid. To shift the poppet in

the opposite direction, the polarity of the voltage applied to the solenoid

leads is reversed and the attractive force between the permanent magnet

armature assembly and the pole piece is reduced. The return spring in the

valve then shifts the poppet to its other sealing position and the permanent

magnet armature assembly is then magnetically attracted to the upper latch.

The upper latch prevents the permanent magnet armature assembly from

attracting itself back to the pole piece when the voltage is removed.

Reversing the polarity again to the solenoid lead wires will create a

powerful attractive force between the permanent magnet armature assembly

and the pole piece and away from the upper latch which will

correspondingly move the poppet to the other shifted position.

Solenoid Poppet Solenoid

Solenoid Spool Solenoid

Long Solenoid Stroke

Cyl A

Exh A Exh BInlet

Cyl B

rma

ure

Coil

Push Pin

Conical Seat

(cushioning)

Poppet

Circuit Board Upper Latch Lower Latch Pole Piece Valve Spring

Figure 1 : Double Solenoid Poppet

Figure 2 : Double Solenoid Spool Design

Figure 3 : Latching Solenoid Design

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Consult “Precautions” page 327 before use, installation or service of MAC Valves..

Technical Info

SOLENOID "A"

SOLENOID "B"

WIRING SCHEMATIC FOR

DOUBLE SOLENOID

Figure 4 : Conventional Double Solenoid

WIRING INSTRUCTIONS AND OPTIONS

As shown in Figure 4, a conventional double solenoid valve requires that the pair of lead wires from each solenoid be wired to an appropriate voltage source,

MAC's latching solenoid technology has the option of being wired in one of the three (3) currently available methods.

FOUR WIRE

As shown in Figure 5, the four wire method enables

the coil to be wired as if it were a conventional

double solenoid. By connecting the yellow lead wire

to positive voltage and the yellow lead wire with

black stripe to negative, the valve will be open to

cylinder port”A”. When positive voltage is supplied to

the red lead wire and negative to the red lead with a

black stripe, the valve will now be open to cylinder

port”B”. Since the negative red and yellow lead wires

are internally connected together, the supply voltage

for each pair of yellow and red lead wires must be

isolated from the other pair (see diagram). Also,

power must not be applied to all four leads

simultaneously or a short circuit condition will occur

possibly damaging the voltage source.

THREE WIRE

Unlike the two wire method ( see Figure 7) which

requires the user to provide the polarity switching

circuitry, the three wire method incorporates the

polarity switching circuitry within the solenoid

enclosure ( see Figure 6). The black lead wire

provided must be connected to positive and is used

as a common. When negative voltage is supplied

to the yellow lead wire with a black stripe the valve

will be open to cylinder port ”A”. When the

negative voltage is removed from the yellow lead

wire with the black stripe and supplied to the red

lead wire with a black stripe, the valve will now be

open to cylinder port “B”. Applying voltage to all

three wires simultaneously or with the wrong

polarity will cause permanent damage to the

switching circuitry in the solenoid cover, and the

valve won’t work.

(+) POS IN A - Yellow

(+) POS IN B - Red

(-) NEG IN A

Yellow/W/Black Stripe

(-) NEG IN B

Red/W/Black Stripe

• No circuit board needed

• Wired as conventional double

• Must isolate pairs of red and

yellow wires from each other

Red/Black Stripe

Red

Yellow

Yellow/Black Stripe

4 WIRE SCHEMATIC FOR LATCHING

YELLOW W/BLACK STRIPE

RED W/BLACK STRIPE

BLACK

• Switching done on circuit

board within valve

• Do not apply power to all

3 wires simultaneously

Red/Black Stripe (-)

Neg In Cyl B Operation

Black (+)

Positive Common

Yellow/Black Stripe (-)

Neg In Cyl A Operation

3 WIRE SCHEMATIC FOR LATCHING

(+) IN A

(-) IN B

(+) COMMON

Figure 5 : Four Wire Latching

Figure 6 : Three Wire Latching