CT1S90 - CT HVAC Timer Series

Littelfuse HVAC Relays
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The CT Series combines a delay-on-make and delay-on-break time delay into one unit and may be used to control fan delays in heating and/or cooling equipment. The CT includes bypass circuitry to allow it to operate with cooling anticipators ? 3000 ohms. It is designed to operate in 24VAC control circuits. Several CT modules may be combined to provide sequencing on of any number of loads and sequencing off of the same loads, such as electric heating elements.


Operation (Delay-on-Make/Delay-on-Break)
Forced Air Heating or Air Conditioning (as shown): When the thermostat closes, the compressor relay is immediately energized. At the end of a fixed delay-on-make delay (T1), the fan relay is energized. When the thermostat opens, the compressor relay is de-energized and the delay-on-break delay is initiated. On completion of the fixed delay-on- break delay (T2) the fan relay is de-energized. If the thermostat is reclosed during the delay-on-break delay, the delay-on-break delay is reset and the fan relay remains energized. If the thermostat is closed when input voltage is applied, the delay-on-make delay (T1) begins as normal.
Reset: Removing input voltage resets the output and time delays.

Property (Mouseover for details) Value
Input Voltage (V) 24 VAC
Input Tolerance (%) ±15%
Input AC Line Frequency (Hz) 50/60Hz
Output Type Solid state
Output Form NO
Output Load Rating (VA) 0.75A steady state 5A inrush at 55°C
Output Voltage Drop (V) ≅1.25V
Time Delay Type Microcontroller
Time Delay Range DOM: 1s; DOB: 90s
Time Delay Tolerance (%) ≤±20%
Recycle Time (ms) ≤300ms
Repeat Accuracy (%) ±5%
Thermostat Anticipator Resistor (Ohms) Anticipator resistor: ≥3000Ω
Insulation Resistance ≥100 MΩ
Dielectric Breakdown ≥2000V RMS terminals to mounting surface
Circuitry Encapsulated
Termination Type 0.25 in. (6.35mm) male quick connect terminals
Mounting Method Surface mount with one #10 (M5 x 0.8) screw
Operating Temperature -40° to 70°C (-40°F to 158°F)
Storage Temperature (F/C) -40° to 85°C (-40°F to 185°F)
Humidity 95% relative non-condensing
Dimensions 2.00 x 2.00 x 1.21 in. (50.8 x 50.8 x 30.7mm)
Weight (lbs/g) ≅2.4oz (68g)
Sample capable No