The global site of the UK's leading magazine for automation, motion engineering and power transmission
18 May, 2024

Twitter link

Device bridges the gap between motor starters and VSDs

01 December, 2014

Eaton claims to have developed a new form of energy-saving motor controller that bridges the gap between fixed-speed starters and variable-speed drives (VSDs). It says that its “variable-speed starter” (VSS) combines the simplicity of a starter with ability to vary the speed of a motor.

No specialist knowledge is needed to install, commission and use the PowerXL DE1 device, which is designed to operate “out of the box” without any adjustments or parameter settings, thus cutting commissioning times by up to 80% compared to conventional VSDs.

Eaton says that the VSS is a reliable, cost-effective form of motor control that will help to raise energy efficiencies in applications where fixed-speed starters were used previously. According to Guido Kerzmann, the company’s electrical product manager for the EMEA region, a key driver when developing the new controller was the need the save energy while avoiding the complexity of a conventional VSD.

“The Energy-related Products (ErP) Directive and the growing levels of machine automation are leading to the increased use of variable-speed drives, even in comparatively simple applications,” he explains. “In many of these applications, however, particularly those involving pumps and fans, VSDs offer too much complexity and functionality, but ordinary motor starters provide no control over speed. Our new VSSs are the ideal solution for these applications where only limited functionality is needed, as they are very simple to use, yet they offer full speed control.”

The VSS comes in two three-phase versions: a 45mm-wide version for use with motors up to 1.5kW; and a 90mm-wide model for motors from 2.2–7.5kW. Both versions have internal motor protection functions as well as motor thermistor and short-circuit protection. The 45mm width is the same as a contactor and the modules can be mounted side-by-side.

There is also a single phase-version for motors from 0.25–2.2kW.

According to Kerzmann, the VSS will be priced “closer to a drive than a starter”, because of its built-in VSD technology.

Key parameters on Eaton's PowerXL DE1 starter can be adjusted quickly using an optional plug-in module

The trip-free design detects regenerative energy fed back from the motor and allows for this. The starters also provide a DC braking function before start-up, which can be useful in fan applications, and they can reduce switching frequencies to ensure that critical device temperatures are not exceeded. An automatic restart function ensures continuous motor operation after a fault.

While the VSS’s standard settings will be suitable for most applications, key parameters such as ramp times, frequencies, and motor protection and terminal arrangements, can be adjusted via a plug-in module using a screwdriver. Alternatively, the VSSs can be configured via external keypads with LED displays and buttons, or via Eaton’s drives Connect software which can be used to set 35 parameters. Parameters can be copied from one starter to another via Bluetooth.

Eaton says that the VSS will help to comply with standards in constant-speed applications where IE2 motors have to be used because IE3 motors would be too large. The devices are also suitable for applications with high start frequencies, and those where there is a high thermal load on the motor.

The VSS has a Modbus interface as standard, and can be integrated with Eaton’s SmartWire-DT wiring system, which is claimed to cut panel wiring time by up to 70% compared to conventional wiring.

The VSS will operate in temperatures from –10ºC to +60ºC without derating, and will withstand 150% overloads for 60s. The starters comply with CE, UL, cUL and cTick requirements, making them suitable for use worldwide.

  • To view a digital copy of the latest issue of Drives & Controls, click here.

    To visit the digital library of past issues, click here

    To subscribe to the magazine, click here



"Do you think that robots create or destroy jobs?"



Most Read Articles