Specifications

22
Handling Thermal Overload Relays
1) Adjusting the Current [Figure 1]
Turn the adjustment dial within the scale so that the total load current of the
motor aligns with the triangle mark. Performance may not be dependable
if the dial is set outside of the range of the scale.
2) Operation Indication [Figure 1]
When the Thermal Overload Relay operates, the white trip indicator will
disappear in the operation indication window. (The white indicator will not
be hidden if the Thermal Overload Relay is tripped in auto-reset status.)
3) Sequence Check [Figure 1]
You can perform a sequence check by pressing the white trip indicator in
the direction of the arrow.
4) Reset Method [Figure 1]
When the Thermal Overload Relay operates, remove the cause of the error
(e.g., an overload) and then press the reset button. (The Thermal Overload
Relay will not reset unless it has cooled sufficiently.)
5) Auto-reset Status and Two-wire Circuits
If the Thermal Overload Relay is in auto-reset status for a 2-wire circuit
and the Thermal Overload Relay resets automatically, the motor will restart
operation automatically. Take adequate precautions for this.
6) Changing between Manual Resetting and Auto Resetting [Figure 2]
Use the following procedure to change between manual resetting and
auto resetting. Reverse the procedure to change between auto resetting
and manual resetting.
① Open the front cover.
② Use a screwdriver or similar device to press the reset button and turn
it 90° clockwise.
③ Make sure that the reset button remains in the pressed state.
④ Close the front cover.
Application in Single-phase Motor Circuits and DC Motor Circuits
The TK12 Thermal Overload Relays are equipped with open-phase
protection. If current does not flow on all phases, the reduced operating
current may cause the TK12 to operate unnecessarily. If you use the TK12
in a single-phase motor circuit or DC motor circuit, perform either ○
A
or ○
B
.
○
A
Connect the wiring so that series current flows to all of the poles.
○
B
Set the adjustment dial to a setting that is 5% to 10% higher than normal.
Mini-Contactors
SK Series
Handling
Figure 1
mark
Adjustment dial
Reset button
Operation indication window
Reset status Tripped status
Sequence
check
Tripping indicator: White
(Shown in black for this description.)
A
B
M M
Reset button
①
②
③
④
Figure 2