How do I find the right relay for my application?

Coil voltage?

• Available coil voltages AC and DC can be found in the catalogue. ComatReleco's technical support team can help you if you cannot find a suitable coil voltage for your application.

Load to be switched?

• Type of load?
  • Is the load to be switched ohmic? Inductive? Capacitive? This is a very important factor to know when selecting a relay/contactor.
• AC? DC?
  • Is the load to be switched supplied with alternating current or direct current? How high is the voltage?

Switching frequency?

• How often should the relay be switched per day, hour, minute or even second? For many switching cycles, a semiconductor relay is recommended, as there is no mechanical contact and the service life is therefore practically infinite.

Environment?

• This includes, for example, the ambient temperature where the relay/contactor is installed. It also includes information about the environment: dusty? Does moisture penetrate? Aggressive gases? Other factors worth mentioning?

Switching small signals – what should be considered?

• If signals in the mA range are to be switched, it is important to select a suitable relay with an appropriate minimum load. Relays with gold-plated contacts are suitable for this purpose. Gold has very good conductivity, which is why small signals can be switched. However, gold tends to weld the contacts when currents are too high. ComatReleco also offers relays with double gold contacts. These double contacts ensure increased switching reliability for control and signal circuits.
• Another alternative to mechanical relays is the use of semiconductor relays. The CSS series from ComatReleco can reliably switch currents from as low as 1 mA (DC) and 35 mA (AC).