JTP-1300 Series Load Banks
Overview
The JTP-1300 Series load banks are designed to test generators continuously, at a power factor of 1pu, without having to utilise the normal operating load. All ratings can be ordered as either manual test mode or automatic load levelling. Automatic load banks are supplied with a set of CTs that the customer installs on the supply cables fed from the generator. The automatic option allows a generator to be loaded at a pre-defined level to allow it to operate efficiently and prevent the buildup of oil and grease within the engine, known as ‘wet stacking’.
All models can be operated in a manual test mode, either using the load step selectors on the load bank control panel, or remotely from a PC, for periodic load testing of the generator.
They can be installed in a fixed location outdoors and the enclosure is weather protected.
The load bank is designed to be hard wire connected and includes M12 terminals for each phase and the neutral conductor. A M10 earth terminal is provided.
The auxiliary supply for the fans and the control system requires a separate 240V 1 Phase 50Hz 10A supply.
A power meter installed in the local control panel shows three-phase voltage, current, active power, reactive power, apparent power, power factor, and frequency of the load to an accuracy class of 0.5, with the same information displayed on the PC screen when in use.
PC Software
Software is provided for installation on the customer’s PC. The software allows the control of the load bank remotely via a RS485 cable and USB adaptor, along with data logging and reporting.
The software allows two control methods, manual or automatic loading. In manual mode the user selects the required load which is then set continuously. In automatic mode the user sets the power and time profile for a full test cycle which is then run automatically.
Data is saved in the software and can be queried either during or after testing. Test data can be exported in a spreadsheet and graphs can be exported as .jpg files.
Resistor Elements
The resistors are a combination of:
- U shaped sheathed, finned elements that utilise a nickel-chromium alloy (NiCr6023) wire in a magnesium oxide powder that provides good thermal and insulation properties, and
- Stainless steel alloy strips supported in a mica panel frame, that are light and robust.
All elements undergo a PFWV test at 2.5kV 50Hz for 1 minute.
The resistor elements are designed to reach no more than 1/3 of the maximum wire operating temperature which ensures a long operating life whilst limiting the change in resistance (±2%), and therefore maintaining a constant load value across the operating profile. The manufacturing tolerance ensures all loads are within ±3% at rated voltage.
Cooling Fans
The cooling system consists of horizontally mounted fans with horizontal air inlets and outlets. Covers over the inlet and outlet vents allow the load bank to be operated outdoors.
Switchgear & Control Systems
The load steps are switched with Schneider Electric contactors protected by fuses on each step for short circuit protection. Each contactor is fitted with auxiliary contacts to provide status feedback.
The control circuit is protected by an MCB.
The control system utilises a highly reliable Siemens PLC to reduce the number of intermediate relays and timers required and simplify manufacture and maintenance.
Protection
Protection consists of:
- fan / master load interlock to prevent loading without the fans running,
- differential air pressure sensors,
- fan motor overload,
- air temperature sensors,
- over-voltage protection,
- load step fuses for short circuit protection, and
- an emergency stop on the local control panel and in the remote-control unit to dump all load and stop the fans.
Included Accessories
The following accessories are included with the load bank:
- 10m RS485 Cable
- RS485 / USB Adaptor
- PC Software (PC not included)
- Operating Manual