High Frequency Power Generation for Aeronautics

SAFAIR OPERATIONS LTD – 127Kva, 120V 3Phase, 400Hz GPU Upgrade – 2017

In March 2017 Gauteng Armature Winders was offered the opportunity to upgrade SafAir’s 400Hz Ground Power Station. The project including the control, monitoring and complete rewind of the 4 pole/32 pole motor-alternator generation unit. Using a Unitronics PLC we controlled the soft starting and excitation of the 50Hz Synchronous motor. The PLC using Modbus communication protocol, measured via a Power Analyzer all motor and alternator parameters and displayed them on the PLC’s HMI interface. The 400Hz Synchronous Alternator’s output was regulated via a high frequency voltage regulator. A wireless adaptor was installed and connected to SafAir’s network and all relevant parameters are now accessed on-line from anywhere on and off site. A complete rewind and service on both machines was carried out including the pre-excitation circuits with solid state control.

Plant Automation


In November 2013 Gauteng Armature Winders was offered the opportunity to automate the concrete billet manufacturing plant. The process included the wireless control of the carrier shuttle, the shuttle once full of the required compound of aggregate was to automatically find the harper which fills or tops up the layer machine. As the process of laying the aggregate was one that can’t be stopped once started, various timing challenges were introduced. Using an ABB PLC and TURK WiFi transmitter the process was automated, position sensors including infrared laser and inductive proximity sensors formed the feedback loop. All user operations were achieved via an ABB HMI. The plant spanned 250m including outdoor and indoor zones. The shuttle had to rotate over the harper to dispatch the aggregate accurately, this was achieved using a two-count proxy sensor on a rotating gear, the two count mathematical model achieved precise movements.

Mining Instrumentation and Automation


In DECEMBER 2016 Gauteng Armature Winders was offered the opportunity to automate the water cannon gun used on open cast mining for gold and uranium extract. Using linear transducers emended inside the hydraulic cylinders, position feedback was achieved. A Unitronics PLC and HMI was used for all logic outputs and user inputs. Via the HMI the operator enters the required parameters of the cut line and pattern. The system would them automatically cut the material/mine at a programmable time and number of cycles as to replicate what the operator would have done. The density of the material was the biggest challenge and this was overcome by fine adjustments to the time incremental parameters decedent on the site. A wireless camera controlled via the site office was installed to have a visual on the environment and production rates.

Electric Motor Service Management


As of 2017 Gauteng Armature Winders has development an electric motor service product. The EMS can be retrofitted to any electric motor, the function of the device is to monitor and notify the end user as to when the motor is due for service, minor or major. The device sends both the client as well as the service provider an email notifying them the service is due. The EMS has no control over the motor other than notification.