K8AK-AW
6
Example Relay Sequence for Overcurrent/Undercurrent Monitoring Mode
<Explanation of operation>
• RY2 (magnet contactor) will be energized in approx. 100 ms when PB1 (startup button) is pressed.
• Use a timer for the K8AK undercurrent alarm (AL2) as a switch from contact “b” to contact “a” will not occur for approx. 250 ms even if the magnet
contactor (RY2) is turned on.
<Timer setting conditions (reference)>
• TA
: Timer (H3YN-2 + socket, Omron)
• Operating mode : Interval mode
• Setting time
: 2 s
Before pressing the startup button (after approx. 1.25 seconds have passed following turning on the power supply of K8AK)
Immediately after pressing the startup button (within approx. 250 ms)
Two seconds after pressing the startup button
Note: 1.
K8AK output contacts will operate (contact “a”) within the setting range for current input values (normal status).
2.
The overcurrent alarm (AL1) and undercurrent alarm (AL2) will operate as follows before the magnet contactor (RY2) is turned on (state
without current input).
• Overcurrent alarm (AL1): Contact “b” for the approx. 1 second interval immediately after the K8AK control power supply is turned on. After that, a switch
to contact “a” will be made as an overcurrent state is no longer present. At that time, there will be a response delay time from
contact “b” to contact “a” of approx. 250 ms.
• Undercurrent alarm (AL2): Contact “b” for the approx. 1 second interval immediately after the K8AK control power supply is turned on. After that, because
a state without current input will continue, an undercurrent will be detected and the status of contact “b” will continue as is.
A1
Magnet contactor for load switching OFF
K8AK
Stop button
T
A
RY1
RY1
RY1
RY2
AL1
AL2
11
14
21
24
PB2
PB1
AL1: K8AK overcurrent contacts
AL2: K8AK undercurrent contacts
Startup button
A2
T
A
Load
RY2
A1
K8AK
A2
A2
A1
K8AK
T
A
RY1
RY1
RY1
RY2
AL1
AL2
11
14
21
24
AL1: K8AK overcurrent contacts
AL2: K8AK undercurrent contacts
T
A
Stop button
PB2
PB1
Startup button
Magnet contactor for load switching ON
Load
RY2
A1
K8AK
A2
A1
K8AK
T
A
RY1
RY1
RY1
RY2
AL1
AL2
11
14
21
AL1: K8AK overcurrent contacts
AL2: K8AK undercurrent contacts
T
A
Startup button
A2
Stop button
PB2
PB1
24
Magnet contactor for load switching ON
Load
RY2
A1
K8AK
A2
Summary of Contents for K8AK-AS1 24VAC/DC
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