3-phase Heater Control Synchronization


Thread Starter

Ted Lechman

I'm thinking of designing a heater control using a single PLC floating point
PLC as well as off-the-shelf solid state switches. Temperature Zones that
have multiple resistive heaters, I will try to configure into a a delta, and
the other heater zones I will try to distribute equally across each of the 3
phases as much as possible. My question is this:

Is there a better way of offsetting the relative phases of the
time-proportional control period, so as to reduce harmonics propagated
through the line and to eliminate stresses and current ratings of fuses and
wire? Should the control periods on each phase be synchronized so that the
phase difference between phases is 120 degrees, or is 0 degs phasing better
-- i.e., zero sequence voltages are better, or what???? Is it advisable to
change the phasing from 120 degs if the resistance between legs is different,
to compensate for the resistive difference???

Thanks for taking the time to respond.
Ted Lechman