Servo Drives Motor And Pump

About Servo Drives Motor And Pump

KEB Servo System

KEB is a leader in drive technology for Plastic machines.

 One application that KEB has a lot of experience in (10+ years & 100,000+ units installed) is operating hydraulic pump motors on injection molding machines.  The post gives an overview of the application and some of the advantages KEB brings to the table

Operating the hydraulic motor from the mains

Historically, injection molding pump motors were connected to the mains power and operated at a fixed speed with a simple on/off control.  With the motor running at a constant speed, the fluid volume and pressure were regulated through hydraulic valves.  While this control method is very straightforward and easy to implement, throttling with valves can be extremely inefficient and can create excessive heating in the system.

 Studies have shown that an injection molding machines hydraulic drives can account for nearly 50% of the machines energy usage So improving the energy usage of the pump goes a long way in improving the overall machine efficiency.

 KEBs Solution ASCL Pump Control

It has been well documented that a pumps speed and flow can be regulated by adding a VFD to the pumps induction motor and controlling the motor speed with simple V/Hz control.  V/Hz control has the added benefit that it soft-starts the motor.  This is a big improvement over line-starting which causes large inrush currents and excessive mechanical wear.

 However, basic V/Hz control has some performance limitations for example, it does not make any adjustments for the induction motors slip because there is no feedback mechanism.  Additionally, V/Hz control will have torque limitations at low speeds.

KEBs ASCL motor control is the answer.  ASCL uses an advanced motor model and continuously measures the VFDs output current and motor back EMF to precisely calculate the motor speed.  The drive is able to make small current adjustments on the microsecond level to provide the optimal operating point, even at reduced speeds

Retrofit Opportunities

Because ASCL does not require any feedback and can be used with any manufacturer of induction motor, it can be easily added to existing installations.

 Servo Pump Control

For even more responsive control, a servo motor can be used instead of an induction motor.  A PM servo motor will provide increased power density, responsiveness, and efficiency compared to an induction motor.  KEBs SCL software functions much like ASCL except it is intended to be used with a Synchronous PM motor.  Again, the software does not require a feedback device and expensive encoder cabling but still provides exceptionally accurate speed regulation across a wide range.  All of KEBs drive platforms support ASCL/SCL software.

Internal PID control

There are many ways the pump control can be handled.  Historically, the PID control was handled in the PLC or a dedicated pump controller and the VFD was simply given a speed command.  But another implementation is to let the VFD manage the PID control for the hydraulic drive.  In this arrangement, a PLC or machine controller would provide the drive with an analog input for the desired pressure setpoint.  A 2nd analog signal which measures the actual pressure is used as feedback in the control and is also fed to the drive.

Advanced Servo Technology for Industrial Demands

Engineered for industrial automation and CNC machinery, this servo drive system features a microcontroller-based digital controller and rotary encoder sensor for superior feedback and accuracy. The combination of air cooling, a mild steel enclosure, and Class F insulation ensures optimal operation even in challenging environments, supporting a wide voltage range and three-phase connection for flexible installations.


User-Centric Design and Safe Operation

Safety and usability are at the heart of this servo drive motor and pump. Overload, overheat, and short circuit protection safeguard both users and equipment, while the IP54 rating offers resistance to dust and water splashes. The digital display and remote control enhance user interaction, enabling operators to monitor and adjust performance easily, even in demanding industrial settings.