Description

Application Scenarios

A machine tool builder has a multi-axis machining centre running 1326AB servomotors under an IMC-class motion controller. The mechanics are sound and the positioning accuracy still meets specification, but one axis fault — and the drive is a discontinued product with no drop-in modern equivalent that matches the same feedback architecture, the same cabinet footprint and the same resolver-to-encoder conversion path.That is the operating reality of 1391-DES45-DI-AQB. These drives sit inside computer-aided closed-loop positioning systems, converting the controller’s analog velocity or torque command into motor current while feeding position information back through the A Quad B output. When a drive fails, the whole axis stops, and the plant discovers that replacing it is not a like-for-like purchase but a redesign of the axis.The second recurring pain point is thermal and environmental. 1391-DES45-DI-AQB dissipates up to 520 W at full load, and the enclosure must keep ambient below 60 °C. Many “mysterious” drive faults trace back to clogged filters, failed cabinet fans or an undersized enclosure rather than the drive itself — which is why understanding the dissipation figure matters as much as the current rating. The third issue is compliance: to maintain the UL listing, power must come from a 1391 isolation transformer, and using a third-party transformer voids it. Plants that discover this during an audit face an unplanned procurement they had not budgeted for.

3. Parameter

Main Parameters	Value/Description
Product Model	1391-DES45-DI-AQB (Bulletin 1391, DES45 rating, DI display interface, AQB encoder output)
Manufacturer	Allen-Bradley / Rockwell Automation
Product Category	Digital AC servo drive / single-axis PWM servo amplifier
Nominal Bus Voltage	300 V DC
Continuous Output Current	45 A RMS — the highest of the three DES ratings, matched to 1326AB-B3E, C2E, C3E and C4 frame motors
Peak Output Current	90 A RMS, with peak current limit adjustable from 20 to 300 % of rated motor current
Continuous / Peak Power Output	15.0 kW continuous, 30.0 kW peak
Input Power Requirements	230 V AC three-phase +10 %/−15 %, 50/60 Hz ±3 Hz; control power 36 V AC single-phase from the 1391 isolation transformer
Control Performance	Speed regulation 0 to 0.05 % of maximum motor speed with 95 % load change; modulation frequency 2500 Hz ±10 %; form factor 1.03 or less; drift 0.07 rpm/°C maximum
Efficiency and Power Factor	85 % minimum drive efficiency at rated load; 95 % minimum power factor
Feedback Output	A Quad B board generating four channels at 2048, 1024, 512 or 256 lines per revolution plus two marker pulses, selectable by switch S1; equivalent to an 845H line driver encoder
Protection and Interfaces	Integral three-pole circuit breaker (38 A RMS, 1300 A interrupt), input transient protection, DC bus shunt regulator with resistor, power line/DB contactor (115 V AC coil); TB2 external signals, TB3 encoder termination, TB4/TB5 on top; up to 600 ft between drive and motor
Environmental and Mechanical	0 to 60 °C operating, 0 to 65 °C storage, 5–95 % RH non-condensing, 1000 m without derating (derate 3 % per additional 305 m); integral 50 CFM fan; approx. 482.6 × 157.5 × 293.6 mm, 34 lb (15.4 kg); 520 W dissipation at full load; UL Listed E59272, CSA LR32334-548