How to select relay
Relays are widely used in control circuits and automatic devices as can control high power output at low power input signals to carry out switching circuits to fix the deviation with respect to the required level of performance. When you select a relay device for a particular electrical circuit necessary to follow some practical recommendations based on the device characteristics.
Instruction how to choose the relay
Determine the desired relay characteristics. First of all, decide the value of the required operation. It is an input parameter value at which the relay switch srabatyvaet.Vtoraya important characteristic - minimal power delivered to the working body which is required to switch from the initial transfer to a working state.
Find out what controlled power is required for the relay to your situation. According to the power control circuit distinguish low power relay (not more than 25 W), medium power (100 W) and high power (a power relay).
Refine the necessary relay response time, ie the time from the submission of the signal prior to the impact on the control circuit. According to this characteristic relays differ by high-speed, slow-motion and time relay.
When choosing a specific design of the relay, pay attention to the features related to the device Disadvantages: speed, the amount of electrical and mechanical life, the presence and magnitude of interference when opening and closing the contacts.
Rate working voltage and current in the relay coil - they must be within the permissible values indicated in the technical documentation. If the coil current is reduced, it leads to decrease in reliability of contact formation. The increased current leads to heating of the winding and decrease the reliability of the relay with a maximum permissible temperature.
Choose relay with several enhanced features operating voltage than those required. Otherwise, when applying for a short-term high-voltage winding can lead to mechanical strain on the yoke and in the contact group. A winding overvoltage may cause insulation breakdown by opening the circuit.
When you select contact groups relay Note the switching current, the nature of the expected load, the total number and the switching frequency in the circuit.