Ledex’s popular B16-L and B17-L latching open frame solenoids are now RoHS compliant. They feature an integral return spring and are specifically designed for latching applications such as security systems, office automation and medical devices.

These compact solenoids provide a maximum force of 25 oz. and a maximum stroke of 0.18 inches in a compact housing less than one inch in length and less than 0.6 inches in width. They offer 10%, 25%, and 50% duty cycles and are available as standard with 3, 6, 12 or 24 VDC input voltages, with optional input voltages up to 120 VDC.   Two plunger cone configurations are available.

For more information on open frame solenoids, contact: Johnson Electric 801 Scholz Drive, PO Box 427, Vandalia, OH 45377-0427; www.ledex.com; (937) 454-2345; fax: (937) 898-8624.

• See the full line of Ledex Open Frame Solenoids

When it comes to accurately controlling gas or fluid flow, linear stepper motors can deliver big benefits in a more compact footprint than other actuation systems.  Controlling gas or fluid flow with closed loop systems requires the use of costly feedback devices that, in addition to adding expense, also add to the overall footprint of the motor, and hence the device or machine.  Alternately, linear steppers operate open-loop (meaning that the motor requires no positional feedback information to work) to modulate the flow of gas or fluid as the motor steps through its travel, and maintain motor position even when power is lost or turned off.

In modulating, mixing or positioning applications that require controlled movements, OEMs increasingly understand that linear stepper motors provide all the accuracy and control they need, while eliminating the costly and often bulky feedback devices of closed loop servo systems.  What’s more, linear steppers deliver constant force over the entire stroke length.  The benefit to the OEM is that, when high starting forces are necessary, they can use smaller motors to replace larger solenoids to get better overall performance in a smaller footprint.

Available in three sizes with unipolar or bipolar configurations, Saia® linear stepper motors boast precision to 0.021mm travel per step over stroke lengths up to 150mm with force up to 80N.  As a result, they are an ideal motion control solution in applications such as:

Gas control – Saia UAL linear stepper motors can be designed in series with a valve to provide accurate and cost effective on/off valve functionality.

HVAC Valve – Saia linear stepper motors are used in all types of valve designs that require natural gas modulation; these designs provide high precision, low hysteresis, and custom output characteristics that deliver the desired process control.

HVAC Damper/Louver – Damper/louver controls use Saia UAL Ø20mm linear motors to provide accurate position control, as well as to control the on/off valve for gas or air flow.

Blending – Saia UCE Ø28mm linear stepper motors feature a long shaft to drop the blending blade into the mixture at the optimum depth for mixing.

Industrial Packing Equipment – Saia UCE Ø28mm linear stepper motors are used to inject just the right amount of foam into plastic cells for safe product shipment.

Medical, Chemical or Food Industry instrumentation – Dosing applications use Saia UAL, UBL, UCE or UCL motors to correctly dispense a substance into a mixture or into a compound being analyzed with chemical reagents.

Locking – Saia linear stepper motors are used in small positioning and adjustment systems, as well as locking/handling systems.

Fluid Controls – Saia linear stepper motors are used to accurately mix fluids, or provide proportional or simple open-close valve functions. These operations are particularly applicable in medical systems, beverage dispensers, coffee machines and heating controls.

The new Saia® Motor EGD 402 Gas Tight Motors and EGD 421 Fail Safe Gas Tight Motors from Johnson Electric are specifically engineered for use with all types of heating gases.  They boast a number of innovative design features that deliver superior and more robust performance, and simplified integration, when compared with motors traditionally used in direct or indirect fire/HVAC equipment, commercial or residential furnaces, and gas valve applications.

“Motors that are traditionally used in gas-related applications have external sealing components and moving o-rings to isolate the stator from the gas environment.  But EGD Series stepper motors accomplish this via internal static sealing components that ultimately result in longer motor life because there are no moving parts that tend to wear out over time,” says Jason Cooper, Engineer at Johnson Electric.  “And unlike competitive motors whose shafts rotate as they move in and out, The EGD Series features an innovative internal anti-rotational spindle nut system to provide true direct linear movement, which can reduce valve complexity and elements.”

Because EGD motors use static sealing, direct linear movement and long-life gas-compatible lubricant, plus Class B insulation and a stainless steel tube between the stator and the rotor to isolate the motor’s winding from the gas environment, “robust” and “reliable” are far more than buzz words. In fact, EGD motors can achieve a minimum of 1 million cycles at operating frequencies of 25 to 200 Hz, in even the harshest environments (-40 to 80 degrees C).  Additionally, EGD motors deliver 10mm travel @ 0.021mm step resolution, and feature low noise with either a unipolar or bipolar coil configuration.

“In addition to the robust performance attributes, what makes EGD Series motors an even more attractive solution in gas-related applications is that they are a virtual snap to design into a machine or appliance.  The design engineer just mates their valve body to the motor’s mounting surface and aligns the shaft to the valve cone, and a simple gasket between the valve manifold and motor mount is all that’s required to complete a gas tight valve,” says Cooper.

EGD 402 Gas Tight motors are used for low power, battery or “green” applications, and will maintain position after power is removed.  The EGD 402 can generate >5N of force throughout the 10mm of stroke and is capable of running at temperatures as low as –40º Celsius.

EGD 421 Fail Safe Gas Tight motors are designed for applications where the gas flow must terminate if a failure or loss of power occurs.  The EGD 421 generates 5N of force throughout its 10mm stroke while delivering reliable operation in temperatures as low as –15º Celsius. Should a failure occur or power be interrupted, fail-safe operation is accomplished with a specialized spring that, without power, moves the shaft back to its de-energized ‘home’ position in ? 1 second.

EGD Series motors are certified according to Gas Appliances Directive 90/396/EEC to perform fail safe gas flow modulation and closing functions.  They can be utilized with any appliance that requires 1^st, 2^nd or 3^rd family of gasses. One potential application is for high end or professional stoves/burners, where the motor’s high resolution (21µm per step) and valve modulation provides a highly controlled and even flame desirable for any chef.

Saia XGT52C86J22Z329 Miniature Micro Switch with custom terminals used in a high-end vacuum cleaner system acts as a safety switch to turn the vacuum on and off.

Mounted on underside of canister it’s able to detect the presence of water.  The application required a high inrush current of 80A.  Saia performed DVT in application to 900,000 cycles under load.

• XG Series Miniature Micro Switch

Johnson Electric introduces the Saia® Compact Driver.  The Compact Driver is a fully integrated stepper motor solution that inherently reduces design and integration time, and improves device performance compared with traditional stepper solutions by virtue of reduced parts count and greater immunity to electromagnetic interference.   Where space and power is at a premium, the Compact Driver’s low power consumption and small footprint make it a particularly attractive motion solution for battery powered portable devices.

The Compact Driver provides 3-wire operation of 28mm Saia motors, including UCL and UCE linear step motors, and UCD and UCB rotary step motors.  The linear Compact Driver solution can provide forces from .1 to 50N with a step resolution down to 0.021mm and distances up to 150mm. The rotary Compact Driver solution can be combined with a Saia UGA, UGD or UGM gearbox to obtain higher torque and RPM outputs, and increase step resolution, all from the same integrated driver board.

“With an over-all smaller foot print, decreased components count on the main PCB, and direct three-wire motor operation that simplifies the design effort for the engineer by eliminating programming and cabling needs, and enhancing EMC immunity, the Saia Compact Driver provides significant advantages over conventional two part stepper motor systems,” says Jason Cooper, Application Engineer.  “A 12v or 24v DC power wire and ground, along with a control wire, are all that is need to control the movement of this powerful integrated stepper motor solution.”

The Compact Driver’s algorithm is programmed to detect the end of the stepper motor’s stroke. This automated end stop detection eliminates noise, reduces mechanical stress, and compensates for transverse distance tolerances, thus decreasing system hysteresis and maximizing operating life.

Additionally, the Compact Driver is available with three different types of control interfaces that can be used for any number of applications where on/off or proportional functions are desired, making it simple to integrate into new and existing device designs. The ON/OFF mode is simply operated by an external switch where the proportional function is controlled by a 0-10v or pulse width modulation (PMW) signal.