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 1st, 2nd or 3rd 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.
Available in unipolar or bipolar configurations, these motors provide constant positioning force to 400 N over full travel lengths to 300 mm in ambient temperatures ranging from -15 to +60°C. Their compact 55 x 55 mm design envelope and NEMA 23 mounting flange enables the ULE series to be mounted in space-restricted applications with great flexibility.