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Bleed Valve Solenoid Polarity
20CB Solenoid coil polarity.

We are using Frame-VI gas turbine machine and using Mark-V control system. while performing shutdown, our machine is tripping due to bleed valve position trouble alarm trip, and found that bleed valve is taking time to open, due to the poor operation of the solenoid valve. We would like to change the solenoid coil 130V DC. our new solenoid coil has three wires two are white colours and one green colour, but this two white colour does not showing any polarity. also, can anybody suggest the wiring philosophy i.e., is there any polarity issue for solenoid coil connections?

1 out of 1 members thought this post was helpful...

There is no polarity for the wiring of 20CB if this is the standard 20CB solenoid manufactured by Laurence or Leslie Controls. White wires connect to positive and negative of the 125 VDC and green to ground or earth.

Hope this helps.

Dear, Thanks for the prompt reply.

1 out of 2 members thought this post was helpful...

Older Laurence/Leslie solenoids WERE polarity sensitive; the newer ones with the electronic module are not.

Unfortunately, on the older, polarity sensitive solenoids both coil leads were black, and there was a small red sleeve placed on one of the black leads to indicate it was the positive lead. And, that sleeve would fall off easily....

But, I think if this was purchased new and recently and has the two white leads it also has the electronic module and is not polarity sensitive. (I believe I even heard that these newer coils could operate on either AC or DC--but that was an unverified rumour....)

Thanks CSA for your valuable reply.