I have an application where we are trying to control level in a reservoir tank based on running of four 55 gal drum unloader pumps. The drum unloader pumps are VFD controlled and we monitor the drum level of each. We currently operate these pumps by sequencing on/off based on the tank level...
Does anyone know of a source that describes all of the different types of switchgear protective relays (i.e. 50/51) with the numbers used and a description of what the relay does?