Three Phase SCR Power Controls from Love Controls

The Love Controls 3027 and 3629 Series Power Controls offer a solid state option for controlling loads. Standard 4 to 20 mA input signal can provide zero-crossover firing or phase angle firing to your load. The 3027 zero-crossover firing power control is best for resistive loads, offering good control and reduced voltage transients and RFI. Cycle time is easily adjustable from one to ten seconds.

The 3692 phase angle firing power control is best suited to inductive loads and special types of loads such as quartz heaters or tungsten loads. The wave form for each half cycle is automatically adjusted to allow only the desired power to the load. Current limiting is also available. These heavy duty units use six SCRs to handle all three phases equally. Phase loss and phase inversion protection is included as well. As with any switch device, appropriate fusing must be used. When specify the power control you need, be sure to specify the fuses and fuse kit(s).


Control Mode:
Zero-cross, two-leg distributive power control to three phase resistive loads.
3629: Three-phase, in line, or inside delta, 6 SCR, phase-angle control of the RMS or average load voltage.
Command Signal:

Input Signal: 3629 Impedance: 3027 Impedance:
4/20 mA 300 ohms 300 ohms
0-5 VDC 100 k ohms 120 k ohms
Potentiometer 100 k ohms 240 k ohms
(1K, 1/4 Watt pot recommended for optimum linearity, 20K permissible)
Control Range: 0 to 98% of line voltage.
Linearity: Output will be linear within 2% of span over entire range of control.
Current Limit Range (3629 only): Field adjustable from 30% to 105% of frame current as specified in the (Amps) term within the model number. Current limit is factory set to 105% of frame current rating.
Zero and Span Adjustments: Multi-turn potentiometers allow zero and span adjustments of ±20% of span.
Dissipation: Approximately 1.5 watts per amp of current per phase will be dissipated by the controller.
Supply Voltage: 3629: 208, 240, 380, 415, 480, or 575 VAC, 3 phase, @ 50/60 Hz; 3027: 208, 240 or 480 VAC 50/60 Hz +10 -15%.
Operating Temperature: 32 to 132°F (0 to 55°C); 0-95% RH, non-condensing.
Electrical Isolation: Heat sink to supply and load voltage 2500 volts peak. Control or command signal to supply and load voltage 1500 volts peak.
Status Indicators (3629 only): LINE OK: Indicates power on all three phases and correct phase rotation; COMMAND: The intensity of this LED is proportional to the command signal; LOAD: The intensity of these three LEDs is proportional to the current in each leg; SHORTED SCR: Indicates when an SCR has failed in the shorted mode; OVER CURRENT: Indicates when an SCR has failed in the shorted mode.
Cooling: Convection cooling on 50 amp unit. Forced air fan cooling on all others.
SCR Voltage Rating: Peak forward and reverse voltage rating 1400V.
SCR DV/DT Rating: 200 volts/µsec minimum.
Loads: 3629: Resistive, Variable resistance, Inductive, Capacitive, Transformer or Lamps; 3027: Resistive only.
Slew Rate: 200 milli-seconds. (Slew rate is the time required for the load voltage to change 63% of the value represented by the command signal.) The current limit action will change the slew rate if the load current is greater than the current rating of the SCRs.