A centrifugal pump is a rotating impeller that moves water into the pump, pressurizing the discharge flow, and has few modes of operation. The centrifugal pump is designed to hold the water with a small valve once the water comes into the pump for the first time. It is the most common type of pump and is very effective in applications with medium-to-high flows. For example, in the chemical industry, the centrifugal pumps are the most economical devices to have, maintain and operate with. For proper operation of the centrifugal pump, you need to know pump modes of operation. Each mode has own unique characteristics and it’s up to you to decide which one is the right for your application.
Start & Stop Control Mode – The start and stop operation mode is generally used to reduce the surges during the start and the stop operation of a centrifugal pump, by gently and slowly accelerating or decelerating the motor. The microprocessor of the motor analyzes the variables and automatically sets up commands which control the motor, while at the same time reduces the possibility of uncontrolled flow in the pump. The centrifugal pump control mode also provides anti-backspin timer.
Braking Control – The braking control mode, or SMB (Smart Motor Braking), is another operation mode which is very efficient for applications where a quick stopping of the motor is required. The braking control mode has zero speed shut off, making the centrifugal pump fully integrated into one compact design. The design provides a clean and easy installation, while eliminating the need for additional hardware like: resistors, breaking contractors, speed sensors and timers. If you are wondering how big the strength of the braking current is, it can be adjusted from 150 to 400 % of full-load current.
Slow Speed With Breaking – For applications that require a centrifugal pump with lower speed, the slow speed with braking is the preferred operation mode. This operation mode can help a lot in positioning or aligning, while providing braking control for stopping. The slow speed acceleration current can be adjusted by the operator from 0 to 450 %, and the adjustments are rated from 7 to 15 %. The braking current, on the other hand, is also adjustable from 0 to 400 %.
Accu Stop – For applications that require controlled position stopping, a centrifugal pump with accu-stop control can be used. With this mode, a braking torque is applied to the motor in order to achieve a relatively low speed, and that speed is kept until the operator gives a stop command. The braking current can be adjusted from 0 to 400 %, while the slow speed current from 0 to 450 %.