A power controller receives an input signal from the temperature controller and, based on the signal, completes or breaks the power circuit to the load.
Well-suited to provide the rapid switching cycles required by PID temperature control, solid state relays (SSRs) can switch from 10 to 75 amps up to 480VAC. Switching can be either zero cross from AC or DC input voltages, or random from DC input voltage. SSRs must be used with a correctly sized heatsink to assure proper service life. SSRs leak current in the off-state.
Capable of zero cross or phase angle operation, or burst firing to act as a solid state contactor, SCRs offer power switching advantages not possible with MDRs or SSRs. Available in ratings from 10 to 1000 amps, up to 575VAC, in 1-phase, 3-phase/2-leg and 3-phase/3-leg versions. Zero cross variable time base extends heater life and permits more accurate control. Phase angle firing permits "soft starting" loads that change resistance over time and temperature (silicon carbide and tungsten heaters). The SCR replaces more expensive and harder-to-control saturable core transformers.
An ideal replacement for mercury displacement relays, the DIN-A-MITE features the same footprint as many comparably rated MDRs. Four styles meet most power switching needs, including CE compliant models, and are available in ratings from 24 to 100 amps, up to 600VAC, in 1-phase, 3-phase/2-leg and 3-phase/3-leg versions. Switching modes include zero cross and solid state contactor. Selected models offer phase angle firing. Touch-safe exterior, and DIN or sub-panel mounting make DIN-A-MITE easy and fast to install. No need to specify an SSR, heatsink and wiring--it's all in one convenient package.