VRAD 506
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Versatile Rotary Actuator Device VRAD 506 series (patents pending) APPLICATIONS ■ Optical beam chopper/shutter ■ Optical element positioning ■ Vending machine actuator ■ Office equipment actuator ■ Air damper/door actuator ■ Automobile actuator ■ Fluid valve actuator FEATURES AND BENEFITS ■ Wide angle, bidirectional rotation ■ Linear angle vs. current profile ■ Low power consumption ■ Compact package size ■ Industry-standard shaft size (0.118 inches / 3.0 mm) ■ Two coils, individually accessible for flexible drive ■ Very low rotor inertia allows responsive control of small loads ■ Connectorized electrical interface for easy installation ■ Front and internal rear shafts allow encoder/position sensor use ■ Disk-drive quality, radially-preloaded ball bearings for long life ■ Smooth, quiet, shock-free motion (no clack-clack at end of travel) ■ Magnetic spring return (fail safe - no torsion bars to wear out or break) ■ True rotary motion with no axial displacement GENERAL DESCRIPTION The VRAD 506 actuator is a very compact, limited rotation Versatile Rotary Actuator Device featuring a magnetic spring return, wide-angle capability, and linear angle-versus-current profile. The high coil resistance allows for low power consumption, and access to two individual drive coils allows flexible single-supply unidirectional or bidirectional operation as well as dual-supply operation. The VRAD 506 actuator provides more than +/-25 mechanical degrees of rotation with only +/-5 volts applied to a single coil or to the series combination of coils. An internal rear shaft allows for use of an encoder or position sensor for closed loop operation. ORDERING INFORMATION To order our standard actuator, just use the simplified part number below. Customization is possible. For additional information, see the datasheet section on Part Numbering Scheme. Document Number: VRAD-506-9019 www.ScannerMAX.com

Versatile Rotary Actuator Device VRAD 506 series (patents pending) SPECIFICATIONS 1. There is no mechanical stop mechanism preventing further rotation, and the actuator may be used with angles well over +/- 45 mechanical degrees with some sacrifice in angle-versus-current linearity. 2. Torque Factor depends on the shaft rotation angle. See the section on Torque production. 3. Magnetic spring stiffness depends on the shaft rotation angle and the model of the actuator. See the section on Magnetic Spring Return. 4. Since Magnetic Spring Stiffness depends on angle, Natural Frequency also has...

Versatile Rotary Actuator Device VRAD 506 series (patents pending) TORQUE PRODUCTION Torque is produced by passing current through one or both actuator coils. Within the actuator, both coils are the same and thus, both contribute equally to torque production. Moreover, current passed through the combination of both coils will produce the same torque as twice the current passed through a single coil. (In other words 100mA flowing through both coils will produce the same torque as 200mA flowing through a single coil.) The actuator produces the maximum amount of torque at its central, rest...

Versatile Rotary Actuator Device VRAD 506 series (patents pending) rotate the shaft 180 degrees which will reverse internal phenomenon and cause rotation in the opposite direction. MAGNETIC SPRING RETURN The actuator features a magnetic spring return, which provides torque in the direction that will restore the rotor to its central resting position. There are two ways to describe the restoration torque - in absolute terms, or in relative terms. In absolute terms, the magnetic spring return is providing zero torque when the rotor is in its central resting position. As you rotate the shaft...

Versatile Rotary Actuator Device VRAD 506 series (patents pending) There is another way to describe the magnetic spring return, and that is in relative terms - dyne centimeters of torque per degree of rotation, which may also be called “spring rate”. If you rotate the shaft clockwise by 1 degree, the restoration torque is approximately 280 Dyne*Centimeters. If you rotate the shaft clockwise by 2 degrees, the restoration torque is approximately 560 Dyne*Centimeters. If you rotate the shaft by 10 degrees, the restoration torque is approximately 2,758 Dyne*Centimeters. Thus, in relative terms,...

Versatile Rotary Actuator Device VRAD 506 series (patents pending) COIL RESISTANCE AND INDUCTANCE Each coil has a resistance of approximately 26 ohms. The series combination of coils has a resistance of approximately 52 ohms. Thus, applying 5 volts to the series combination of coils will consume slightly less than 100mA of current. Each coil has an inductance of approximately 2.35 millihenry, but this will only be observed if one coil is used and one coil is completely disconnected. There is mutual inductance between the two coils, and short circuiting the second coil will reflect an...

Versatile Rotary Actuator Device VRAD 506 series (patents pending) ACTUATOR LINEARITY AND SENSITIVITY Since the torque versus angle profile is approximately proportional to the cosine of rotor angle, and also since the magnetic spring restoration torque versus angle profile is also approximately proportional to the cosine of rotor angle, these two cosines curves cancel out (as long as there is no static load on the rotor). Because of this, the angle versus current profile for this actuator is nearly linear up to +/-45 degrees, and can even be driven well past this angle. The graph below...

Versatile Rotary Actuator Device VRAD 506 series (patents pending) ACTUATOR DRIVE TECHNIQUES Since the VRAD-506 actuator has two coils which each have a relatively high resistance, this provides great flexibility in driving the actuator. Below you will see several drive techniques described, but there are certainly other possibilities as well. The techniques below are analog in nature, but digital (i.e. PWM) drive is also of course possible. Single voltage, two-position (unidirectional actuation) The circuit above shows a simple way to activate and deactivate the actuator, for example, in a...