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I read in the datasheet of the DOLD OA5611 that the maximum relay cycles/s is 10 cycles/s. Now I want to know what are the risks for the relay if I control it with a switching frequency more than 10 Hz. It's not specified in the datasheet what the conditions for the current and voltage for the maximum switching frequency are.

Otherwise i find in other relays datahseet that there is two values for the maximum operating frequency:
Mechanical max operating frequency which is 18000 operations/hour,
Electrical max operating frequency 1800 operations/hour @ rated load.
My questions:

  1. What is the used maximum operating frequency to respect in the datasheet.
  2. Can we exceed the Electrical max operating frequency if the relay is used with current and voltage less than the rated load.

From what I understood we can use the relay with frequency more than the Electrical max operating frequency if the used current and voltage are less than the rated load. But we cannot exceed the mechanical max operating frequency in any condition. am I right ?

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    \$\begingroup\$ If you need to switch a relay more than 10 times a second, you probably shouldn't be using a relay. \$\endgroup\$
    – Nick Johnson
    Nov 4, 2015 at 14:03
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    \$\begingroup\$ using any device outside its specifications is likely to result in an undefined failure mode. \$\endgroup\$
    – Icy
    Nov 4, 2015 at 14:05
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    \$\begingroup\$ Not to mention, this relay is rated at 3e5 - that's 300,000 - cycles. At 10Hz, you'll exceed that in just 8 hours. \$\endgroup\$
    – Nick Johnson
    Nov 4, 2015 at 14:12
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    \$\begingroup\$ Is depend on the used current see the graph switching cycles vs switching current \$\endgroup\$
    – R Djorane
    Nov 4, 2015 at 14:16
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    \$\begingroup\$ @Icy no is the same thing, every time that your contact is closed in every command \$\endgroup\$
    – R Djorane
    Nov 4, 2015 at 14:19

1 Answer 1

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Likely it will sit there and quiver - it's a mechanical system, the parts have mass, it takes time to accelerate the mass...

If you need something that switches fast, a solid-state relay is a convenient off the shelf "brick" or a power transistor may be more appropriate - a mechanical relay is not the tool for the job.

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  • \$\begingroup\$ I'm not sure is depend on the application: if your load is sensitive to the voltage drop this can cause problem because your SSR can fail to close (short-circuit) this is very dangerous for safety applications. \$\endgroup\$
    – R Djorane
    Nov 4, 2015 at 15:09
  • \$\begingroup\$ ...it's also "very dangerous for safety applications" to run a device outside of specifications. \$\endgroup\$
    – Ecnerwal
    Nov 4, 2015 at 15:13
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    \$\begingroup\$ No, if your device fail to open instead of close is more safe, this is the case of a safety relay, the use of SSR is not a solution in safe applications. \$\endgroup\$
    – R Djorane
    Nov 4, 2015 at 15:16

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