The new hand-held Sigma LT load bank controller from Asco Power Technology is designed to fill an entry-level niche for remote and local controllers for portable load banks.
Asco Power Technology said the Sigma LT is designed to network up to 25 load banks through CAN bus communications protocol. Operators can monitor and control all networked load banks, or a single unit in the network, up to 800 ft. away. The company said the ability to vary, accept or reject load on a single unit within a network is a feature available only on this remote controller. Single-unit control would enable data centers, for example, to simulate hot zones to determine how an HVAC system reacts to temperature changes at specific server rack locations.
Networking is an important capability, the company said, because a series or mix of smaller load banks can provide larger, more flexible test capacity, especially for rental fleets. Smaller load banks also make it easier to get test capacity into restricted areas, eliminating the need for long cable runs from large, street-based load banks, the company said. Networking multiple units provides redundancy during 24-hour commissioning tests.
Networked load banks also give a better overall load resolution, the company said. For example, three 100 kW load banks and a 200 kW load bank can be put on one network giving a capacity of up to 500 kW and a resolution of the smallest load step on the 100 kW unit. This can be particularly beneficial if the supply on the test is on a roof or basement, where a single 500 kW load bank could not access, the company said.
Networking smaller load banks for a 24-hour commissioning test also provides the benefits of redundancy and finer load step resolution, Asco said.
The Sigma LT incorporates a 4.3 in. color touch screen that displays 3-phase voltage, power, current and frequency readings and selected load. It also is designed to provide true, de-rated loading when the working voltage is less than load bank nominal voltage. Data logging and statistical data can be downloaded to a USB flash. The digital load select toggle switches were designed to overcome the typical block loading deficiency of standard toggle switches. The individual load step LEDs and an integrated, one-second delay synchronizes load step changes, producing clean load changes not possible with conventional toggle switch technology, the company said.