Agilent Technologies 34970A manual Switching Frequency, Replacement Strategy

Chapter 8 Tutorial

Relay Life and Preventative Maintenance

Switching Frequency

Relay contacts heat up as they switch significant power. The heat is dissipated through the leads and the body of the relay. As you increase the switching frequency to near its maximum, heat cannot dissipate before the next cycle. The contact temperature rises and the life of the relay is reduced.

Replacement Strategy

There are essentially two strategies that you can use for preventative maintenance of the relays on the switching modules. The strategy that you choose depends upon your application, the consequences of a relay failure in your system, and the number of relay cycles during a measurement session.

The first strategy is to replace each relay as needed after it fails or becomes erratic. This is suitable if you are switching higher loads on only a few relays on the module. The disadvantage of this strategy is the inconvenience of continually replacing relays as they near the end of their life at different times.

The second strategy is to replace all relays on the module or simply purchase a new module as the relays near the end of their life. This strategy is best suited for those applications where all relays on the module are switching similar loads. The failure of several relays over a relatively short period of time may indicate impending failures on other relays switching similar loads. This strategy decreases the risk of failure during actual use at the expense of replacing some relays that may have useful life remaining.

Note: In both cases described above, you can use the 34970A Relay Maintenance System to track and even predict relay failures.

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