LOAD BANKS CONTROLS
SIGMA PC SOFTWARE
Sigma PC software for Windows™ replaces the Intelligent Hand-held Terminal (IHT) and converts a PC into the load bank controller allowing enhanced load control along with transient speed instrumentation, full data acquisition reporting with graphical displays, real time data such as crest factor recovery times and % errors necessary for testing to ISO8528.
Sigma PC software is the solution for witness testing, product verification, medium and high voltage testing.
SIGMA INTELLIGENT HAND-HELD TERMINAL (IHT)
Housed in a robust, industrial polycarbonate and polyamide enclosure with IP65 protection, membrane keyboard and back-lit graphic LCD, the IHT allows remote working whilst still having live display information showing all the main electrical parameters and data capture.
The displays are designed to simplify the testing, setup and adjustment of the supply-on-test for the operator.
When carrying out full load testing one page shows all the true RMS three-phase measurements of voltage (V), frequency (Hz), current (A), power (both kW and kVA) and power factor (Cos Ø).
For transient-response testing, the voltage and frequency of the last load change are captured and displayed on the dynamic graph including maximum and minimum data. The status line includes the elapsed time since the last load was applied.
SIGMA LT (NEW)
Sigma LT is the new cost effective entry level Sigma control system for Avtron and Froment load banks. Sigma LT offers local digital toggle switch and optional hand-held for remote operation and is available on selected 2000 and 3000 series resistive load banks. Networking capabilities are also available for up to 25 units and controllable with a single hand-held.
SIGMA DECADE SWITCH CONTROL
Decade switch control provides straight forward manual control with quick and easy load selection with load accept and reject buttons. Indicator lamps show the current status of load bank operation, load control and status of the supply-on-test. Load step resolutions of 0.1kW, 1kW or 10kW are available depending on load bank size.
SITE LOAD CORRECTION (SLC)
Sigma Site Load Correction automatically maintains the required level of loading on a gen-set to prevent problems associated with light loading. External current transformers (CTs) are connected to the Sigma control system to provide site load information. When the site load increases the load provided by the load bank decreases. When site load decreases the load provided by the load bank increases.
The maximum load level required on the gen-set is set within Sigma and may be adjusted by an external decade switch that gives 12 individual load steps. Each load step is applied only when site load is continuously below that of the load step threshold for a predetermined time. Load steps are released when site load increases above the present selected load step.
Modbus communications protocol allows integration of a Sigma load bank with the gen-set control system, test cell automation and building supervisory and monitoring systems through PLC, HMI or SCADA systems.
The Modbus protocol is implemented on the load bank or the Intelligent Hand-held Terminal (IHT) using an RS232 serial port (or optional IAP Ethernet converter). Modbus on the IHT provides full control and instrumentation for one or multiple load banks. Modbus on the load bank provides a means of monitoring both operation and instrumentation on a single load bank with the option of direct load bank. If the load bank is setup for Site load correction, the load bank set points can be setup via Modbus.
Toggle Switches are the most basic option of standard load bank control. Its simple, straight forward operation is perfect for basic resistive load testing.