Liquiflo vs. Other Allen Bradley Drives: What Sets Them Apart?

Allen Bradley is one of the big players in the market when it comes to industrial automation. They offer a big number of drives, each of which is tailored for specific applications. One of these offerings is the Liquiflo drive. This article walks you through the technical specifications of the Liquiflo drives as to what makes this drive different, or similar to other Allen Bradley drives.

Technical Specifications

Technical specifications of any drive can be broken down into various subsections. Each of which can be separately examined for comparison with other drives or one’s needs. For Liquiflo drives features are focused on precision and reliability. We will be focusing on the original Reliance Electric LiquiFlo drives, not the LiquiFlo 2.0.

Service Conditions

The Liquiflo drives have a maximum AC line distribution system capacity of as much as 85,000 amps symmetrical fault current for 460 VAC units. However, in cases where circuit breakers are used in place of fuses, the short circuit rating is limited to 65,000 amps. In comparison, other Allen Bradley drives, specifically the PowerFlex series, have similar fault current capacities. However, the configuration may vary depending on the model and application.

Control methods also differ between Liquiflo and other drives. Liquiflo utilizes an all-digital vector, sinusoidal pulse-width-modulation (PWM) control for precision control and smooth operation. Where there are other drives that also employ digital vector and PWM control, the Liquiflo’s implementation is optimized for torque control and speed precision. Liquiflo drives maintain a power 0.96, hence is comparable to the other Allen Bradley models when it comes to energy efficiency.

Liquiflo drives have an operating line frequency of 50/60 Hz with a tolerance of ±2 Hz and a line voltage variation from -10% to +10%. The other Allen Bradley drives provide similar capabilities, however, Liquiflo drives have an exceptional line dip performance. It offers a maximum Line Dip Ride-through of 0.5 seconds (or 500 milliseconds) for Flux Vector Control (or FVC) and as much as 999.9 seconds for V/Hz and SVC modes.

Motor and Remote Control Specifications

Liquiflo drives can support motor lead lengths of 76 meters or 250 feet total. This feature aligns with many Allen Bradley drives but may require additional accessories for longer distances. However, the remote operator control wire length (or up to 303 meters or 1000 feet) set the Liquiflo drives apart, exceeding the limits of most other models.

Liquiflo drives provide an analog speed resolution of 1/1024 (10 bits) resolution, and a speed accuracy of 0.1%. High-end PowerFlex models match this level of precision, however, Liquiflo drives are optimized for critical applications. Moreover, the speed adjustable range spans from 0 RPM to maximum speed in vector mode, with a speed regulation of 0.01% (FVC) and 0.5% (SVC).

Liquiflo drives particularly excel in Torque control response and linearity. The Liquiflo drives feature a torque control response between 180 and 220 Hz, and a torque linearity of +3%, with optimal settings of parameters. The other Allen Bradley drives also feature robust torque control, but Liquiflo drives stand out with their consistent performance across varying loads. Liquiflo drives also offer software-selectable carriers of 2 kHz, 4 kHz, or 8 kHz. This feature reduces noise, and is comparable to other models but implemented more efficiently.

Environmental and Operational Conditions

Like other Allen Bradley drives, Liquiflo is designed to provide reliable operation in challenging environments. It functions at temperatures ranging from 0°C to 55°C (32°F to 131°F); however, the ambient storage temperature is between -40°C to 65°C (−40°F to 149°F). It does not require additional cooling measures like some of the drives. Furthermore, the Liquiflo drives can tolerate 5% to 95% non-condensing humidity, which is a standard feature in many Allen Bradley drives.

Terminal Strip and Communication Specifications

Input and Output Terminals

Terminals 12-15 are reserved for speed reference input, supporting 10 V at 50 K ohm input impedance or 20 mA. The digital inputs 1-8 correspond to terminals 16-24. These digital inputs include functions such as Run/Jog, Reset, Stop, and Start, offering a user-friendly layout. Analog output terminals 10-11provide a scaled signal of 0-10 VDC or 4-20 mA.

RS-232 Communications

The Liquiflo drives support RS-232 communication with terminals designated for XMIT, RECV, and COMMON. This is a common feature across Allen Bradley drives, and makes Liquilfo drives compatible with legacy systems.

Encoder Feedback Device Specifications

The Liquiflo drives support 2, 4, 6, or 8 pole motors, and provide a speed control range of 1:600 with a typical response of 15 Hz. Encoder feedback compatibility includes 15 V differential quadrature encoders with resolutions up to 4096 PPR. The other Allen Bradley drives vary in resolution capabilities.

Input Signal Response Times

The response times in the Liquiflo drives highlight the efficiency. Keypad and terminal strip start commands have response times of 150 milliseconds (V/Hz) and 130 milliseconds (Vector Regulation). While, for analog speed/trim reference, the response times reduces to 5 milliseconds. These performance metrics might outperform other models.

Motor Overload Protection

Liquiflo provides electronic motor overload protection (Class 10) in accordance with NEC article 430. However, it does not include speed-sensitive overload protection, thermal memory retention, or motor over-temperature sensing. These limitations are consistent with many Allen Bradley drives, and additional measures may be required for specific applications.

Application Scenarios

The Liquiflo drives can be employed in various applications. For example, in precision manufacturing, high torque control response and accurate speed regulation might come in handy. Similarly, in material handling applications, the extended motor lead lengths and remote control capabilities simplify the installation process. For pumping applications in water treatment and oil refining, the Liquiflo drive has the ability to handle voltage dips, maintaining uninterrupted performance under varying conditions. The RS-232 communication and encoder feedback compatibility helps with integration with advanced systems.

Conclusion

Liquiflo drive is a standout option within Allen-Bradley’s lineup for its precision, reliability, and flexibility. Where other Allen-Bradley drives might share features, the Liquiflo drives are optimized for torque control and speed regulation. Environmental resilience is just another cherry on top. It is a robust drive with the ability to answer questions in modern automation.

When it comes to Allen-Bradley drives, we at DO Supply have you covered! We carry thousands of different AB parts, drives, motors, and accessories to modernize your automation solution. We also carry a couple of LiquiFlo drives, though these parts are for the LiquiFlo 2.0, and can be found here. If you don’t see something specific that you need, feel free to give us a call, and our team of experts will help get you exactly what you need. We also have many more blogs just like these, but we think you would like this one specifically. Thank you for reading.