Values indicating the characteristics and performance guarantee standards of the switches.
The rated current and rated voltage, for instance, assume specific conditions.
The service life when the rated load is connected to the contact and switching operations are performed.
The service life when operated at a preset operating frequency without passing electricity through the contacts.
Threshold limit value that a high voltage can be applied to a predetermined measuring location for one minute without causing damage to the insulation.
This is the resistance value at the same place the dielectric strength is measured.
This indicates the electrical resistance at the contact part.
Generally, this resistance includes the conductor resistance of the spring and terminal portions.
Vibration range where a closed contact does not open for longer than a specified time due to vibrations during use of the snap-action switches
Max. shock value where a closed contact does not open for longer than a specified time due to shocks during use of the switches.
This is the maximum switching frequency required to reach the end of mechanical life (or electrical life).
This is the maximum temperature rise value that heats the terminal portion when the rated current is flowing through the contacts.
When applying a static load for a certain period on the actuator in the operation direction, this is the maximum load it can withstand before the switch loses functionality.
When applying a static load for a certain period (in all directions if not stipulated) on a terminal, this is the maximum load it can withstand before the terminal loses functionality (except when the terminal is deformed).
Resistance load is a power factor of 1 (cosØ = 1) where the load is only for the resistance portion. The displayed switch rating indicates the current capacity when using AC current.
Differing from AC, since the direction of current is fixed for DC, the continuous arc time lengthens when the same voltage is applied.
Since an inrush current of 10 to 15 times the rated current flows for an instant when the switch is turned on for the lamp, adhesion of the contacts may occur.
Therefore, please take into consideration this transient current when selecting a switch.
Since arc generation due to reverse voltage can cause contact failure to occur when there is an induction load (in relays, solenoids and buzzers, etc.), we recommend you insert a suitable spark quenching circuit (see figure below).
(1) r = more than 10 Ω
(2) In an AC circuit,
Can be used for both AC and DC circuits.
r = R
C: 0.1 μF
|For DC circuits only.|
|Can be used for both AC and DC circuits.|
Contacts may adhere due to the starting current at the start of motor operation which is three to eight times the steady-state current.
Although it differs depending on the motor, since a current flows that is several times that of the nominal current, please select a switch taking into consideration the values in the table below.
To make the motor rotate in reverse, use an ON-OFF-ON switch and take measures to prevent a multiplier current (starting current + reverse current) from flowing.
|Motor type||Type||Starting current|
|Three-phase induction motor||Squirrel-cage||Approx. 5 to 8 times current listed on nameplate|
|Single-phase induction motor||Split-phase-start||Approx. 6 times current listed on nameplate|
|Capacitor-start||Approx. 4 to 5 times current listed on nameplate|
|Repulsion-start||Approx. 3 times current listed on nameplate|
A current that is approximately two times that of the starting current will flow when reverse rotation is caused during operation. Also, when using for a load that will cause transient phenomena such as when operating the motor in reverse rotation or switching the poles, an arc short (circuit short) may occur due to the time lag between poles when switching. Please be careful.
|Example of 1-pole motor reverse rotation circuit
|Example of single-phase induction motor
(capacitor) strong-weak switching circuit
|Example of three-phase motor
reverse rotation circuit
In the case of mercury lamps, florescent lamps and the capacitor loads of capacitor circuits, since an extremely large inrush current flows when the switch is turned on, please measure that transient value with the actual load and then either use the product keeping within the range of the rated current or after verifying the actual load.
The humidity range varies with the temperature. Use within the range indicated in the graph below.
(The allowable temperature depends on the switch.)