I know with larger motors you do not want them to start with a contactor above 30HP or so because they will 'sag' the power in the plant and the inrush current can be insane. We typically put anything at or above 30HP on a VFD or Soft Start unit.
Is there any such worry about a large 480V heating element? They are resistive loads, so there should be no worry about inrush. Is there a certain point you would want to switch to an SCR controller even if you want 100% of the heat all the time?
A 60kW heater, for example, would pull just over 72A at 480VAC. Is a simple contactor still a suitable way to turn it on and off, or is there merit in controlling this with an SCR instead?
Is there any such worry about a large 480V heating element? They are resistive loads, so there should be no worry about inrush. Is there a certain point you would want to switch to an SCR controller even if you want 100% of the heat all the time?
A 60kW heater, for example, would pull just over 72A at 480VAC. Is a simple contactor still a suitable way to turn it on and off, or is there merit in controlling this with an SCR instead?