AC and DC circuit in the ability of the button switch is very different, need to confirm the rated value.
DC control capacity of the occasion is very low. This is mainly because the DC does not like the exchange of zero point (current zero crossing point), so once it is difficult to eliminate the arc, the arc time is very long. And the current direction of the same, so will appear contact migration phenomenon contact will because of the uneven and cannot be disconnected, may lead to misoperation.
Some kinds of load of constant current and surge current differ greatly. Need to be used in the range of allowable surge current. When the circuit is closed, the surge current is larger, the consumption and migration of the contacts are larger, and the failure of the contact can not be switched due to the fusion and migration of the contacts.
In the case of containing the electric induction can produce the reverse induction voltage, the higher the voltage, the greater the energy consumption and the migration of the contact also increases,
Therefore, required to confirm the rated conditions, in the ratings in marked volume control, but that alone is not enough, in is switched on and off when the voltage, current waveform, the load are special load circuit must be respectively for the actual equipment testing to confirm. Small voltage and current applications need to use a small load of products. The use of silver contact for general purposes, may lead to reduced contact reliability.
When the push button switch is out of the range of mini type and high load, the relay is connected with the load.
Determine the aircraft rated conditions are as follows:
Inductive load: power factor above 0.4 (AC), time constant 7ms (DC).
Lamp load: a load that is equivalent to a constant current of 10 times the surge current.
Motor load: a load that is equivalent to a constant current of 6 times the surge current.
Note: inductive load is particularly important in the DC circuit, so it is necessary to fully understand the value of the time constant (L/R) of the load.