Octal Relays - ECN Electrical Forums

Why do we have 2 different pin configurations for the plug in octal relays 2 pole double throw c/o contacts and what problems have these caused by plugging in and forgotten to check.

We use them a lot in our 33/11 kV substations for alarms and the like.

here in NZ Email relays have 3 - 6 to the coil.
European relays 2 - 7 to the coil.

Strange.

Have never seen an octal relay with anything other than 2+7 for the coil here in the US.

Apparently a holdover from the days of octal vacuum tubes, where 2+7 were (almost always) the heater/filament pins.

Posted for RODALCO:

Quote

Today had something different from the usuall utility jobs.

I had to liven up the mining transformers for the Puhoi tunnel on SH 1 North of Orewa.

do voltage and rotation, polarity checks etc.

Also fit data loggers because of possible voltage dips.

Northern gate way alliance are drilling through one of the hills to ease our northern traffic flow.

11 kV supply to 3 x SDF fuse switches.

750 kVA 11000 -- 240 / 415 Volts
500 kVA 11000 -- 240 / 415 Volts
600 kVA 11000 -- 433 Volts ( 250 P - N )
1000 kVA 11000 -- 1050 Volts for drilling machine

Had to do the SD switching as well as operating all the mining switchgear.

got some piccies if you are interested.

Cheers

Raymond RODALCO

The Email octal relay. We have these in 24Vdc, 110Vdc and ac and 240Vac with these pin configurations:

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Substation drawing from substation alarms:

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