H2W Technologies, Inc. has designed and manufactured a non-commutated DC actuator, otherwise known as a voice coil actuator, designed for vacuum operation in a cryogenic environment. H2W has worked with several aerospace customers, developing manufacturing processes and material selection to provide customers with the ability to design motors with low outgassing in UHV conditions, which meet NASA’s Collected Volatile Condensable Materials and Total Mass Loss requirements.
The cryogenic environment required the voice coil to have elements designed to withstand the harsh environment, which required specific material selection regarding bearings, shaft, and magnetic material and coatings. Additionally, this motor had thermal sensors or RTDs integrated to monitor the temperature of the windings.
The actuator is capable of a continuous force of 3.7 pounds [16.5 N] and a peak force of 11.1 pounds [49.4 N] at a duty cycle of 10% (i.e., 1 second on and 9 seconds off). With a moving mass of just under 0.4 pounds [3.6 kg], this allows for a maximum theoretical continuous acceleration of nearly 10 G’s.
This has a stroke of 0.6” [15.2 mm], and has a Force Constant of 1.0 lbs./amp [4.5 N/amp]. This relatively large stroke allows for a greater range of applications that may require greater strokes and high accelerations.
|Device Type||Moving Magnet|
|Stroke||0.6 in||15.2 mm|
|Radial Clearance||0.025 in||0.64 mm|
|Moving Mass||0.35 oz||160 grams|
|Total Mass||0.84 oz||382 grams|
|Resistance @ 20C||15 +/- 2.2 ohms|
|Inductance @ 20C||5 mH|
|Electrical Time Constant||0.17 msec|
|Motor Constant||0.87 lbs/√watt||3.85 N/√watt|
|Force Constant||3.4 lbs/amp||15 N/amp|
|Back EMF||0.34 V/ips||15 V/m/sec|
|Force @ 100% Duty||3.7 lbs||16.5 N|
|Power @ 100% Duty||18.3 watts|
|Current @ 100% Duty||1.1 amps|
|Force @ 10% Duty||11.1 lbs||49.5 N|
|Power @ 10% Duty||163 watts|
|Current @ 10% Duty||3.3 amps|
|Outside Diameter||1.6 in||40.6 mm|
|Housing Length||2.55 in||64.8 mm|