‘Smart-Drive’ can slash granulator running costs
ALL Zerma granulators are now available with the new Zerma ‘Smart-Drive’ system, a technology that can reduce electrical consumption by 20-60% on granulators.
Traditional methods for starting fi xed- speed motors are direct-on-line (DOL) or Star-Delta starters. More recently, however, soft start motor controllers have become the starting method of choice because of the smooth control of the starting and stopping of the motors which result in reduced high in-rush currents and premature mechanical failure to the motor and associated couplings. However, the Zerma Smart-Drive system uses an energy saving soft-starter, intelligent load monitoring, energy optimisation and controlled stopping in a smartly designed and competitively priced unit.
Using the basic premise of torque being directly proportional to the square of applied voltage, the energy-saving system tracks the load applied to the shaft of an AC induction motor and intelligently and dynamically changes the voltage being applied, resulting in reduced current and power consumption. This feature is in addition to all standard soft-start features. These capabilities very often provide energy savings in the 20-60% range which can have a signifi cant effect on the overall cost of ownership. It is well-known in the motor industry that heat is the biggest cause of motor failure.
By allowing a motor to reach and operate at a temperature 10°C above its specified maximum temperature rating will reduce the motor’s expected life by 50%. This is often referred to as the motor ‘half-life’. The Smart-Drive system is proven to signifi cantly reduce both motor heat and vibration when in energy-saving mode, which invariably reduces motor failure rates and increases motor ‘up’ time, both significant contributors to the overall cost of ownership.
Excess energy consumption is not only an unnecessary cost on your energy bill, but it also serves to damage your equipment as the excess energy is released through the windings of the motor in the form of heat, vibration and noise. High in-rush current and uncontrolled torque when starting your motors almost certainly causes you problems. The advantages of using a soft-starter as opposed to, for example, direct-on-line or star-delta, are now comprehensively documented. The soft-start is in effect an electronic clutch:
Gradual uptake of power, smooth, step-less acceleration, resulting in less stress on you and your valuable equipment.
Improved power factor
The Smart-Drive system is integrated in-house by Zerma at its manufacturing plant in China. A number of other benefits are achieved with the technology, not least being that of improved power factor at all load cycles and thereby reduction in kVA. A strong case for the possibility of an increased number of starts per hour is also created.
And, although granulators do not as such accelerate, there is the potential for adjustable acceleration time, which again reduces stress on the machine and motor.
It also prevents dips in supply when starting larger motors, allowing you to attach more equipment to a single supply. Due to the fact that voltage or current is applied gradually, without the voltage and current transients, precise control over the current limit is achieved.
This system is most effective on granulators with variable material infeed rates, where the machine has periods with little or no load between periods of high load.