Control.com - Nerds in Control

Hi There,

Though i have worked with a few and set up a few load share systems I am still trying to get my head around how the load share signals between isoch governors are produced/interpreted. For example a Cat system would use a 0-10V signal between 3 units with say 6V being a 30% loading point.

In my head I can see one generator monitoring its loading, seeing its at 30% and providing a 6V output to suit, which the other generators pick up on and set their output to 30% as well. This assumes a master/slave situation but i know the system does not work that way. Take any one load share module out, including the one that could be the 'master', and all the others continue to work fine. So it seems that they all not only see the 6V signal but also adjust it. I can't get my head around how that works.

I guess its the same for mA and CAN type signals too. Can anyone help enlighten an ignorant guy please?

For analogue load share lines, the device connected to the lines is a wheatstone bridge of resistors. One side of the bridge is the load share lines, the other is to the load sharers internal circuit. By measuring across the bridge, the load sharer knows whether to increase of decrease fuel/excitation to control kW/VAr and hence adjust it's voltage on the load share lines.

Using CAN, it's done by communication. Each set transmitting to the others how much load share it has (using one CAN line for both kW and kVAr) and adjusting the load share until all sets are sharing power at the desired levels (usually the same amount as a %age of their full load.

For more info see the DSE7510 controller which uses CAN for load share. www.deepseaplc.com