The 1391B-AA22 is a Pulse Width Modulated (PWM) Servo Controller manufactured by Allen-Bradley, designed for single-axis applications. This controller transforms a three-phase input frequency of 50/60 Hz into a variable AC voltage, with regulated frequency, amplitude, and phase. Its output is directly proportional to an analog command, modulating the speed and torque of a connected motor. It is optimized for use with 1326 permanent magnet AC servomotors by Allen-Bradley.
The controller components are arranged on an open frame, protected by a slide-on cover, making them suitable for panel-mounted installations within enclosures equipped with climate control features like fans or heaters based on the installation site. The unit itself includes a fan to manage heat dissipation from the heatsink.
For maintaining UL listing, installation requires the use of an Allen-Bradley 1391 isolation transformer. Using third-party transformers will void the UL listing for this controller.
There are two versions of the 1391 Servo during its production: Series A and Series B, which share identical physical dimensions and mounting requirements. Series B offers enhanced control capabilities and can be used with the Series A controller, but not vice versa, to prevent operational issues.
The 1391B-AA22 Servo Controller is known for its compact design, primarily for controlling the speed and torque of a servo motor in closed-loop positioning systems, frequently used in automated systems for precise motion control. It features a nominal bus output voltage of 300V AC, continuous output current of 22.5A (peaking at 45A), and an output power rating of 7.5kW (peaking at 15kW). The input circuit breaker is rated at 26A (RMS) with a maximum interrupt rating of 1300A (symmetrical). It has a static gain of 1.5 times the rated motor/RPM, a form factor of 1.03, and operates with an efficiency of 85% at minimum load. The peak output current can be adjusted from 20-200% of the rated motor current, up to a maximum of 90A. It operates within a modulated frequency range of approximately 2.5 KHz (+/- 10%) and has an operational drift of 0.07 RPM per degree Celsius, with zero dead band. It includes a heatsink fan with an output of 50 CFM.
The controller provides a full load 300V DC power supply, with a transformer delivering 230V AC (three-phase) input power at 50-60Hz, and 35.5V AC (single-phase) control input voltage. It has a transformer input tolerance of +10% to -15%, thermal dissipation of 55W at 20% load and 275W at full load, and operates within an ambient temperature range of 32-140°F with 5-95% non-condensing humidity. It is suitable for operation up to 1000 meters without performance derating and weighs approximately 28 kg (12.69 lb), with dimensions of approximately 19 inches x 6.2 inches x 10.64 inches.
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