Time Delay Relays
Dedicated - HVAC
CT SERIES
Delay-on-Make/Delay-on-Break Timer
Description
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 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.
V = Voltage
FR = Fan Relay
FS = Fan Switch
CR = Compressor Relay
THMS = Wall Thermostat
Wiring Diagram
L1
N
Features & Benefits
FEATURES
Delay-on-Make and
Delay-on-Break in
one unit
Totally solid state
and encapsulated
Interconnectability with
other CT modules
BENEFITS
Simplifies wiring and installation, and optimizes
efficiency of heating and cooling systems
No moving parts to arc and wear out over time and
encapsulated to protect against shock, vibration,
and humidity
Combine modules to provide sequencing on of
a number of loads and sequencing off of the
same loads
Accessories
Ordering Information
MODEL
DELAY-ON-MAKE
(FIXED SECONDS)
DELAY-ON-BREAK
(FIXED SECONDS)
P1015-64
(AWG 14/16)
Female Quick Connect
These 0.25 in. (6.35 mm) female terminals are
constructed with an insulator barrel to provide
strain relief.
P1023-6 Mounting bracket
The 90° orientation of mounting slots makes
installation/removal of modules quick and easy.
P1015-18 Quick Connect to Screw Adapter
Screw adapter terminal designed for use with
all modules with 0.25 in. (6.35 mm) male quick
connect terminals.
CT1S30
CT1S45
CT1S8
CT1S90
CT30S1
CT45S45
CT5S300
1
1
1
1
30
45
5
30
45
8
90
1
45
300
If you don’t find the part you need, call us for a custom product 800-843-8848
© 2016 Littelfuse Protection Relays & Controls
www.littelfuse.com/ct
www.littelfuse.com/
Rev: 1-A-062116
Time Delay Relays
Dedicated - HVAC
CT SERIES
Accessories
C103PM (AL) DIN Rail
35 mm aluminum DIN rail available in a 36 in.
(91.4 cm) length.
P1023-20 DIN Rail Adapter
Allows module to be mounted on a 35 mm DIN
type rail with two #10 screws.
Specifications
Time Delay
Type
Range
Repeat Accuracy
Tolerance
(Factory Calibration)
Recycle Time
Input
Voltage
Tolerance
AC Line Frequency
Output
Type
Form
Rating
Voltage Drop
Protection
Circuitry
Dielectric Breakdown
Insulation Resistance
Mechanical
Mounting
Dimensions
Termination
Environmental
Operating/Storage
Temperature
Humidity
Weight
Thermostat
Microcontroller
1 - 600s
±5%
±20%
≤ 300ms
24VAC
±15%
50/60 Hz
Solid state
NO
0.75A steady state, 5A inrush at 55°C
≅
1.25V
Encapsulated
≥ 2000V rms terminals to mounting surface
≥
100 MΩ
Surface mount with one #10 (M5 x 0.8) screw
H
50.8 mm (2”);
W
50.8 mm (2”);
D
30.7 mm (1.21”)
0.25 in. (6.35 mm) male quick
connect terminals
Function Diagram
DELAY-ON-MAKE
DELAY-ON-BREAK
V = Voltage
FS = Fan Switch
FR = Fan Relay
T1 = Delay-on-Make
T2 = Delay-on-Break
R = Reset
= Undefined Time
-40° to 70°C / -40° to 85°C
95% relative, non-condensing
≅
2.4 oz (68 g)
Anticipator Resistor: ≥ 3000 Ω
© 2016 Littelfuse Protection Relays & Controls
www.littelfuse.com/ct
www.littelfuse.com/
Rev: 1-A-062116
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