Endeavour Automation

  Soft starters A soft starter is a solid-state device that protects AC electric motors from damage caused by sudden influxes of power by limiting the large initial inrush of current associated with motor startup. They provide a gentle ramp up to full speed and are used only at startup (and stop, if equipped). Ramping up the initial voltage to the motor produces this gradual start. Soft starters are also known as reduced voltage soft starters (RVSS). Soft starter applications Soft starters are used in applications where: Speed and torque control are required only during startup (and stop if equipped with soft stop) Reducing large startup inrush currents associated with a large motor is required The mechanical system requires a gentle start to relieve torque spikes and tension associated with normal startup (for example, conveyors, belt-driven systems, gears, and so on) Pumps are used to eliminate pressure surges caused in piping systems when fluid changes direction rapidly Benefits...

  A braking unit or sometimes called a braking chopper is an electrical switch (normally IGBT) that manages the DC bus voltage by switching the braking energy to a resistor where the braking energy is converted to heat.  By activating the braking function, it can manage the DC bus voltage level and avoid overvoltage nuisance tripping by switching the braking energy to a resistor where the braking energy is dissipated in the form of heat. This means that the braking unit or chopper is the controlled path - like a switch - (IGBT) that allows regenerative motor energy to flow and the braking resistor is the element where this regenerative motor energy will be dissipated in.        

  How Variable Speed Drives Save Energy? Most motors are designed to rotate at a set speed based on the number of magnetic poles built into them and the supply voltage and frequency applied. They cannot alter their speed. Even for fixed speed systems, it can be difficult to find a motor that rotates at the correct speed for its designated application. Therefore, extra parts such as gears, dampers or variable speed drives are often required. Variable speed drives provide effective speed control of AC motors by manipulating voltage and frequency.  Controlling the speed of a motor provides users with improved process control, reduced wear on machines, increased power factor and large energy savings. Most applications can be grouped into the following torque categories: Constant torque load applications such as conveyors often require a starting torque close to the rated torque of the motor, and show only small changes as they approach rated speed Linear torque load applications s...

  A variable frequency drive (VFD) is a type of motor controller that drives an electric motor by varying the frequency and voltage of its power supply. The VFD also has the capacity to control ramp-up and ramp-down of the motor during start or stop, respectively. Even though the drive controls the frequency and voltage of power supplied to the motor, we often refer to this as speed control, since the result is an adjustment of motor speed. There are many reasons why we may want to adjust this motor speed.  For example, to Save energy and improve system efficiency Convert power in hybridization applications Match the speed of the drive to the process requirements Match the torque or power of a drive to the process requirements Improve the working environment Lower noise levels, for example from fans and pumps Reduce mechanical stress on machines to extend their lifetime Shave peak consumption to avoid peak-demand prices and reduce the motor size required In addition, today’s d...

  VFDs are are extremely susceptible to dust, debris, moisture, and overheating. If you are using a VFD in an area that is consistently taking in dust, debris, or moisture the operating life of your VFD will be shortened. In environments with high humidity, such as wastewater treatment plants, your VFD is at risk for circuit board corrosion from moisture being sucked into the cabinet through the cooling vents constantly. This, compounded by possible infrequent use, can enable moisture to build up without time for heat and ventilation to dry it out. To avoid issues caused by humidity, ensure that the operating environment and storage space for your VFD is clean and dry, and consider a dehumidifier to dry out the air (ensure the dehumidifier does not leak near any electronic equipment). For extreme humidity or wash-down environments a NEMA 4, 4X or 5 enclosures may be necessary. Another common cause of VFD failure due to environment is the clogging of cooling vents by airborne partic...

  Harmonics are currents or voltages with frequencies that are integer multiples of the fundamental power frequency, which in the U.S. is 60 Hertz. If the first fundamental frequency is 60 Hz, then the second is 120 Hz, and the third is 180 Hz. Here are a few examples of issues that might be related to harmonics. Flickering lights are a common symptom of a power quality issue. A potential source of flickering lights is machinery with rapid fluctuations in load current or voltage. These machines include large motors when they are starting up, machinery with cyclo-converters such as rolling mill drives and mine winders, as well as machines that use static frequency converters such as AC motors and electric arc furnaces. Overheated transformers and tripped breakers could be a sign of harmonic issues, which occur when non-linear loads that draw current in abrupt pulses, rather than in a smooth sinusoidal manner, cause harmonic currents to flow back into other parts of the power system....

  During a break down of a 630 KW Ac drives, we observed the silicone gel leaked out from U phase IGBT’s. Silicone gels provide the dielectric insulation in insulated gate bipolar transistor (IGBT) power modules to prevent partial discharge, inhibit moisture ingress and keep out contaminants from the internal circuitry. The junction temperatures of these power modules are located between 150  o  C and 175  o  C and these temperatures will increase to 200  o  C in the near future. I would like to share our observations of this particular case.        A.      Temperature sensors of all 3 phases found proper. Resistance was approx. 4.71 K ohms. B.      Silicone gel leaked out from 6 IGBTS of U phase. C.      Drive overheat protection was bypassed. So drive was not tripping at high temperature. D.     Temperature sensing circuit’s track was da...