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1201 Variable-Frequency AC Drive

The 1201 provides reliable, efficient, cost-effective variable-frequency (V/Hz) or flux vector control of a wide variety of motors. It incorporates the latest technologies in insulated gate bipolar transistors (IGBTs), pulse-width modulation (PWM), and digital signal processing (DSP) to deliver optimum motor performance, complete programmability, and simplicity of operation.

Performance Flexibility

The 1201 accommodates a broad range of performance requirements. Units may be configured for constant-torque operation for heavy-duty cyclic loads, variable- torque operation for medium duty requirements, or extended-torque operation for centrifugal loads such as fans and pumps. The drive operates in a transducerless vector control mode that does not require a feedback device and produces full torque to base speed with full starting torque. For demanding applications, an incremental encoder or resolver interface can be added for precise position, velocity, and torque regulation and improved dynamic performance. Dual- and triple-encoder interfaces are also available for position-following or dual-transducer applications. Variable-frequency control is alternately available for applications that do not require critical velocity or torque control. Several controller options are available to meet differing application requirements.

Motor-Independent Design

The 1201 can operate any standard- or inverter-duty AC induction or synchronous motor, making it ideal for retrofits and new applications alike. A unique, pro- prietary digital current regulator (DCR) tunes the drive continuously in real time, eliminating the usual current-loop tuning process required by conventional drives. Digital space vector (DSV) control can be selected for reduced motor noise and low current ripple.

Auto Tuning

Once routine electrical connections have been made, simple-to-use auto-tuning features adjust virtually all motor- and load-dependent parameters. No motor maps are required. Simply enter basic motor information from the nameplate, and the advanced setup routines do the rest. The drive is completely tuned within minutes.

Application Software

A wide variety of software options is available to tailor the 1201 to an application, from a fully featured velocity/torque control for general purposes to a host of powerful programs pre-engineered for specific applications. Customization is possible with many programs using UEdit®, a Windows-based programming tool that lets users extend an application using IEC 1131 standard ladder diagrams and function blocks.

Digital Setup, Easy Operation

A keypad and liquid crystal display provide a simple interface for setting and viewing operating parameters and diagnostics. All controller settings are made digitally for precision and repeatability. Readouts and fault messages are displayed in readily understandable language. An optional graphic display provides a variety of visual formats for accessing drive information.

Multiaxis and Tandem Operation

A built-in high-speed synchronous communication port allows the motion of multiple slave drives to be precisely coordinated. With optional master/slave software, the velocity ratio and position phasing of the drives can also be controlled. Multiple motors can be operated in parallel from a single drive using variable-frequency control. Two drive sections can be operated in tandem for high-power applications.

Power Quality

A unique bus architecture provides near-unity overall power factor and low harmonic line currents at all motor speeds. All units available with six-phase(12-pulse) configuration. High power units have nine-phase (18-pulse) or twelve-phase (24-pulse) configurations for minimizing line harmonics in critical applications.

Protection and Advanced Diagnostics

The 1201 monitors its operating conditions and provides a comprehensive set of overload, short circuit, and other electronic protective features to ensure safe, reliable operation. Faults indications are displayed in plain language. A log maintains a history of fault occurrences and externally triggered events.


An RS-422/485 serial interface is provided for connecting the drive to a process controller, communication network, or programmable controller. A variety of popular communication protocols is available through software or optional Anybus modules. Optional Bluetooth and MaxStream modules provide short- and long-range wireless communications. An RS-232 connection is also provided for connecting a personal computer. Windows-based PCs can set up, monitor, and control a network of drives using optional UEdit® software. Unico’s Drive Talk™ application provides remote interface capabilities for the iPhone™ and iPad™.


Compact and rugged, the 1201 is available as an open chassis for mounting inside an enclosure. It can be foot-mounted to a wall or subplate or flange-mounted through a cutout to dissipate heat outside an enclosure.



• 24-bit digital signal processor (DSP) for fast processing
• 512 kilobytes battery backup memory for application setup data
• 1.5 megabytes scratch pad memory and 6.0 megabytes firmware memory
• Clock/calendar maintains accurate time during power outage
• Sine-coded PWM waveform output for improved torque performance
• High-switching-frequency IGBT devices for smooth, quiet operation
• Digital current regulator for high-speed operation and fast response
• Digital space vector control for reduced motor noise and low current ripple
• Flux vector control for full starting torque and full torque to base speed
• Variable-frequency operation for simple control of motor speed
• Internal control loop for maintaining speed with sudden load changes
• Automatic field weakening for speeds up to three times base speed
• Unique architecture for high power factor and low total harmonic distortion
• Integral dynamic braking for fast deceleration or energy absorption
• Power disturbance ride-through for reducing nuisance trips
• User-programmable analog and digital inputs and outputs
• Through-hole heat sink mounting of chassis units for dissipating heat externally
• Optional NEMA 1 (IP20) and NEMA 3R (IP23) or NEMA 4 (IP66) enclosures

Ease of Installation, Setup, and Maintenance

• Automated setup features require no chart recorders or meters
• Software calibration and adjustment eliminates tuning components
• Digital parameter adjustment for precise and repeatable settings
• Software input and output scaling eliminates potentiometers
• Complete, self-contained package requires minimal option boards
• Identical control boards across full power range reduces spare parts

Ease of Use

• Touch keypad for easy parameter adjustment and access to displays
• Two line descriptive plain-language display with numerical and bar graph readouts
• Optional graphics display for charting drive information in real time
• Comprehensive plain-languge fault diagnostics with time-stamped fault log

Safe, Reliable Operation

• Extensive electronic protection circuits
• Tolerant of AC line voltage and frequency fluctuations
• S-curve acceleration reduces shock and extends equipment life
• Multilevel security code prevents unauthorized parameter changes
• Lockout of local operator controls for safe remote operation