Application Scenarios

A municipal water treatment plant operates a 15 HP centrifugal pump on its backwash supply line. The original across-the-line starter provided only on/off control, causing water hammer each time the pump started and forcing operators to throttle a discharge valve to regulate flow—a practice that wasted energy and accelerated valve wear. The plant replaced the starter with a 1336F-BRF150-AA-EN, wiring the drive’s analog input to a 4–20 mA flow transmitter and configuring the built-in process PI function to modulate pump speed directly from the flow signal.

The change eliminated water hammer entirely, as the 1336F-BRF150-AA-EN’s programmable acceleration ramp brought the pump from zero to operating speed over 15 seconds instead of the near-instantaneous across-the-line start. More importantly, the drive’s V/Hz control reduced pump speed to match actual flow demand rather than running at full speed against a throttled valve. Within one quarter, the plant recorded a 28% reduction in pump motor energy consumption—a direct result of the 1336F-BRF150-AA-EN’s ability to match motor output to process demand rather than fighting a mechanical restriction.

Parameter

Technical Principles and Innovative Values

• Innovation Point 1: Dual Control Mode Architecture. The 1336F-BRF150-AA-EN offers both standard Volts-per-Hertz (V/Hz) control and sensorless vector control in a single drive. For fan and pump loads where torque requirements rise with the square of speed, V/Hz mode provides adequate performance with simple commissioning—no motor parameters beyond nameplate data are required. When an application demands higher low-speed torque, such as a positive-displacement pump or a conveyor starting under load, switching to sensorless vector mode delivers markedly improved torque response without an encoder. This dual-mode flexibility means one spare drive covers a wider range of applications, reducing inventory requirements for maintenance departments supporting mixed loads.
• Innovation Point 2: Integrated Process PI for Closed-Loop Control Without External Hardware. The 1336F-BRF150-AA-EN includes a built-in proportional-integral (PI) process control function that allows the drive to regulate a process variable—pressure, flow, level, or temperature—directly from an analog sensor input. In the water treatment application above, this meant the drive could accept a 4–20 mA flow signal and adjust pump speed to maintain setpoint without a separate loop controller, PLC, or signal conditioner. For small pump skids and standalone fan systems, this integration eliminates an entire control panel layer, reducing wiring, cabinet space, and potential failure points.
• Innovation Point 3: Legacy Reliability with Modern Spare Parts Support. The 1336 PLUS II platform earned its reputation in the 1990s and 2000s for robust construction and straightforward diagnostics. The continues that tradition with microprocessor-based protection against overcurrent, overvoltage, undervoltage, ground fault, and output short circuits. While Rockwell has discontinued the line in favor of PowerFlex drives, the remains widely supported through surplus and refurbished channels. For facilities with existing 1336 PLUS II installations, this means a failed drive can be replaced with a form-fit-function spare rather than requiring a full control panel redesign and PLC reconfiguration.