Time Delay Relays – Application Data
Definition:
Time Delay is defined as the controlled period between the functioning of two events. A Time Delay relay is a combination
of an electromechanical output relay and a control circuit. The control circuit is comprised of solid state components and
timing circuits that control operation of the relay and timing range. Typical time delay functions include On-Delay, Repeat
cycle (starting off), Interval, Off-Delay, Retriggerable One Shot, Repeat cycle (starting on), Pulse Generator, One Shot,
On/Off Delay, and Memory Latch. Each function is explained in the table below. Time delay relays have a broad
choice of timing ranges from less than one second to many days. There are many choices of timing adjustments from
calibrated external knobs, DIP switches, thumbwheel switches, or recessed potentiometer. The output contacts on the
electromechanical output relay are direct wired to the output terminals. The contact load ratings are specified for each
specific type of time delay relay.
Understanding the differences between all the functions available in time delay relays can sometimes be a daunting task.
When designing circuits using time delay relays questions such as:
“What initiates a time delay relay?”
“Does the timing start with the application or release of voltage?”
“When does the output relay come on?”
must be asked.
Time delay relays are simply control relays with a time delay built in. Their purpose is to control an event based on time.
The difference between relays and time delay relays is when the output contacts open & close: on a control relay, it
happens when voltage is applied and removed from the coil; on time delay relays, the contacts will open or close before
or after a pre-selected, timed interval.
Typically, time delay relays are initiated or triggered by one of two methods:
• application of input voltage (On Delay, Interval On, Flasher, Repeat Cycle, Delayed Interval & Interval/Flasher).
• opening or closing of a trigger signal (Off Delay, Single Shot & Watchdog).
These trigger signals can be one of two designs:
• a control switch (dry contact), i.e., limit switch, push button, float switch, etc.
• voltage (commonly known as a power trigger).
To help understand, some definitions are important:
Input Voltage:
Control voltage applied to the input terminals (see wiring diagrams below). Depending on the function,
input voltage will either initiate the unit or make it ready to initiate when a trigger signal is applied.
Trigger Signal:
On certain timing functions, a trigger signal is used to initiate the unit after input voltage has been applied.
As noted above, this trigger signal can either be a control switch (dry contact switch) or a power trigger (voltage).
Output (Load):
Every time delay relay has an internal relay (usually mechanical) with contacts that open & close to control
the load. They are represented by the dotted lines in the wiring diagrams. Note that the user must provide the voltage to
power the load being switched by the output contacts of the time delay relay.
The following tables contain both written and visual descriptions on how the common timing functions operate. A Timing
Chart shows the relationship between Input Voltage, Trigger Signal (if present) and Output Contacts.
SECTION 5
5/2
M a gn e c r a ft S o lu t io n G ui de 1 0 5 A
FUNCTION DEFINITION TABLE
Function
A.
ON DELAY
Power On
B.
REPEAT CYCLE
Starting Off
C.
INTERVAL
Power On
D.
OFF DELAY
S Break
Operation
When the input voltage
U
is applied, timing delay
t
begins. Relay contacts
R
change state after time delay is complete. Contacts
R
return to their shelf state
when input voltage
U
is removed. Trigger switch is not used in this function.
When input voltage
U
is applied, time delay
t
begins. When time delay
t
is
complete, relay contacts
R
change state for time delay
t.
This cycle will repeat
until input voltage
U
is removed. Trigger switch is not used in this function.
When input voltage
U
is applied, relay contacts
R
change state immediately
and timing cycle begins. When time delay is complete, contacts return to shelf
state. When input voltage
U
is removed, contacts will also return to their shelf
state. Trigger switch is not used in this function.
Input voltage
U
must be applied continuously. When trigger switch
S
is closed,
relay contacts
R
change state. When trigger switch
S
is opened, delay
t
begins.
When delay
t
is complete, contacts
R
return to their shelf state. If trigger switch
S
is closed before time delay
t
is complete, then time is reset. When trigger
switch
S
is opened, the delay begins again, and relay contacts
R
remain in
their energized state. If input voltage
U
is removed, relay contacts
R
return to
their shelf state.
Upon application of input voltage
U,
the relay is ready to accept trigger signal
S.
Upon application of the trigger signal
S,
the relay contacts
R
transfer and the
preset time
t
begins. At the end of the preset time
t,
the relay contacts
R
return to
their normal condition unless the trigger switch
S
is opened and closed prior to
time out
t
(before preset time elapses). Continuous cycling of the trigger switch
S
at a rate faster than the preset time will cause the relay contacts
R
to remain
closed. If input voltage
U
is removed, relay contacts
R
return to their shelf state.
When input voltage
U
is applied, relay contacts
R
change state immediately
and time delay
t
begins. When time delay
t
is complete, contacts return to
their shelf state for time delay
t.
This cycle will repeat until input voltage
U
is
removed. Trigger switch is not used in this function.
Upon application of input voltage
U,
a single output pulse of 0.5 seconds is
delivered to relay after time delay
t.
Power must be removed and reapplied to
repeat pulse. Trigger switch is not used in this function.
Upon application of input voltage
U,
the relay is ready to accept trigger signal
S.
Upon application of the trigger signal
S,
the relay contacts
R
transfer and
the preset time
t
begins. During time-out, the trigger signal
S
is ignored. The
relay resets by applying the trigger switch
S
when the relay is not energized.
Input voltage
U
must be applied continuously. When trigger switch
S
is closed,
time delay
t
begins. When time delay
t
is complete, relay contacts
R
change
state and remain transferred until trigger switch
S
is opened. If input voltage
U
is removed, relay contacts
R
return to their shelf state.
Timing Chart
U
R
U
R
U
t
on
off
on
off
t
t
t
t
t
t
t
t
t
R
U
S
R
close
open
on
off
t
t
E.
RETRIGGERABLE
ONE SHOT
U
open
on
off
t
t
R
F.
REPEAT CYCLE
Starting On
G.
PULSE
GENERATOR
H.
ONE SHOT
U
R
U
R
U
S
R
U
S
R
U
S
R
close
open
on
off
close
open
on
off
close
open
on
off
on
off
on
off
t
t
t
t
t
t
Pulse
t
Pulse
t
t
I.
ON/OFF DELAY
S Make/Break
t
t
t
t
J.
MEMORY LATCH
S Make
Input voltage
U
must be applied continuously. Output changes state with every
trigger switch
S
closure. If input voltage
U
is removed, relay contacts
R
return to
their shelf state.
S
= Trigger Switch
R
= Relay Contacts
t
= Time Delay
U
= Input Voltage
Magnecra f t So l u t io n Gu i de 1 0 5 A
5/3
SECTION 5
S
close
Advantages of the TDRSOX/SRX Time Delay Relays
Time Adjustment Dial
Fine Tune the Time Setting.
Removable Knob
Prevents Tampering.
Output Indication
Red LED Light.
Integrated DIP Switch
Simplifies the Programming
of the Functions and Timing.
Input Indication
Green LED Light.
Optional Side and Top
Flange Mounting
Flexibility in Mounting
Techniques.
SECTION 5
Socket Compatible
Makes for Easy Installation
and Replacement.
Flexible Mounting
Mounts Directly on a DIN Rail or Panel.
5/22
M a gn e c r a ft S o lu t io n G ui de 1 0 5 A
The Complete
System
Solution!
The TDRSOX/SRX series is a dual-function, dual-voltage time delay relay that offers a wide
timing range. This cost sensitive timer features DIP switches that allow the user to set the
function modes and choose between eight separate time scales. The knob on top is used
for fine tuning the time setting. This dual adjustment design allows for supreme flexibility
and timing accuracy. The dual LEDs allow the user to know when power is present at the
coil and when the output is energized.
The SOX series features both On Delay and Interval functions, in contrast the SRX series
has the capability of handling the Off Delay and Retriggerable One Shot functions. Please
see the Application Data at the beginning of this section for a complete description of the
above four functions. Combining all of this into one affordable package is the reason
Magnecraft continues to be a leader in providing the most comprehensive line of control
and timing relays.
• Offers a “one stop solution” for your power management system.
• Several configurations available to meet your individual needs.
• Switching capabilities up to 12 amps.
• The broad timing range meets most timing requirements.
• Dual voltage coils eliminate the need to specify AC or DC. (AC only for 240).
• The two LED status indicators; indicate status at a glance. The green LED is on
when power is applied to the input terminals. The red LED blinks during
timeout and is on when the output is energized.
• Integrated DIP switch simplifies the programming of the functions and timing.
• Color and appearance designed for high visibility in all environments.
• Engineering availability allows for customized control system solutions.
SECTION 5
www.magnecraft.com
Magnecra f t So l u t io n Gu i de 1 0 5 A
847-441-2540
5/23
TDRSOX/SRX Time Delay Relays/DPDT
12 Amp Rating
Input Indication
Green LED
Recessed Potentiometer
for Fine Tuning the
Timing Setting
SELECTING TIME RANGES
TIME RANGE
0.1 sec - 1 sec
1 sec - 10 sec
10 sec - 100 sec
0.1 min - 1 min
1 min - 10 min
10 min - 100 min
0.1 hr - 1 hr
1hr - 10 hr
DIGITAL SWITCH POSITION
II
OFF
OFF
OFF
OFF
ON
ON
ON
ON
III
OFF
OFF
ON
ON
OFF
OFF
ON
ON
IV
OFF
ON
OFF
ON
OFF
ON
OFF
ON
C
UL
US
UL Listed When Used With
Magnecraft Sockets.
Output
Indication
Red LED
UL Recognized
File No. E43641
DIP Switch for
Function/Timing
General Specifications (@ 25°C)
Output Characteristics
Number and type of Contacts
Contact Material
Current rating
Switching voltage
(UL 508)
Units
TDRSOX
DPDT
Silver Alloy
12
240 AC, 50/60 Hz
30 DC
1/3 @ 120VAC
1/2 @ 240 VAC
B300
100
Red
12, 24, 120
240
80% to 110%
5
2.5
Green
A, C
8
0.1….1
1….10
10….100
0.1….1
1….10
10….100
0.1….1
1….10
10
1
150
50
100,000
10,000,000
2500 AC
1000 AC
UR, UL
-20…+85
-20…+55
IP 40
85
TDRSRX
DPDT
Silver Alloy
12
240 AC, 50/60 Hz
30 DC
1/3 @ 120VAC
1/2 @ 240 VAC
B300
100
Red
12, 24, 120
240
80% to 110%
5
2.5
Green
D, E
8
0.1….1
1….10
10….100
0.1….1
1….10
10….100
0.1….1
1….10
10
1
150
50
100,000
10,000,000
2500 AC
1000 AC
UR, UL
-20…+85
-20…+55
IP 40
85
@ 240 VAC, 24 VDC
Minimum Switching Requirement
Indication
Input Characteristics
Voltage Range
Operating Range
Maximum consumption
Indication
Timing Characteristics
Functions Available
Time Scales
Time Ranges Available
LED
A
V
V
HP
HP
Pilot Duty
mA
% of Nominal
LED
(See page 5/3)
VAC / VDC
VAC
AC
DC
VA
W
SECTION 5
Tolerance
Repeatability
Reset Time
Trigger Pulse Length
Performance Characteristics
Electrical Life
Mechanical Life
Dielectric strength
Environment
Product certifications
Ambient air temperature
around the device
Degree of protection
Weight
Mechanical Setting
Constant Voltage and Temperature
Maximum
Minimum
Operations @ Rated Current (Resistive)
Unpowered
Input to Contacts
Between Open Contacts
Standard version
Storage
Operation
sec
sec
sec
min
min
min
hr
hr
%
%
ms
ms
V
V
°C
°C
grams
5/24
M a gn e c r af t S ol u t i on G u id e 1 0 5 A
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a ft
uid
05
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