quick question about tube relays

[Scott_fx]

Hello,

This is probably really off topic but I thought i'd come to the experts since a search brought up nothing.

I was wondering if a "tube relay" acts the same way as a traditional relay?

The reason I ask is that I am currently installing two butler tube amps and a butler tube crossover in my car and i thought it would be a great little addition if the relay was also a tube.

thanks in advance,

scott

[DigitalJunkie]

Yea,sorta.
They usually have a delay,the exact amount of delay depends on the type of relay tube. (commonly 15,30,45 or 60 seconds)

Essentialy they use a small heater (looks like a tiny wirewound resistor) to heat a bi-metal contact..once it's warm,it 'trips'.

Not an instantaneous 'trip' like a normal relay,wether that's an issue or not is up to you.

One more note,they're usually 6.3V,you might be able to find 12V versions though..Personally I've never seen a 12V relay tube,but I assume they're available.

[Scott_fx]

thank you for your response. do you know if they are too fragile for the automitive environment?

[DaveInVA]

They are pretty robust. Usually not good for much current. They also have a delay after the power is removed from them as the contact won't shift until the heater/bimetal cools a bit. They come spst in NO, NC and flasher (they alternately open and close at a set time).

Dave

[Scott_fx]

thank you very much.

[kevinkr]

6V, 12V and 24V-26V thermal delay relays in various glass envelopes are common. Both Amperite and Potter Brumfield made a selection in both 9 pin miniature and in octal types as well.

For example a typical PB or Amperite relay would be the 26NO60T which denotes a 26V heater, normally open contact, and 60 second delay.

Check out the Amperite website here: http://www.amperite.com/Uploads/g.PDF
(I would have attached this document, but at 430K it is just too large.)

Rated contact currents are typically not much over 1 - 3A which might be a concern in your application.

They are mechanically rugged, but can suffer thermal fatigue after many years of use. (Either they don't close or they end up taking more or less time to close than when new.) I have seen very few that didn't work though.

[Scott_fx]

thank you, amperage shouldn't be a concern of mine, the relay will control turn on circuits on the amps which draw milliamps.

now to figure out how to make this look good (hope this application and miss use of a tube doesn't offend anyone) :-)

[kevinkr]

Shouldn't be a problem, you should do what delights you..

Thermal delay relays are readily available surplus, who knows you may even find them on ePay..

Post some pix when you get your project done..

[coresta]

Hi ! I'm using XT90As from the former Thomson-CSF in my OTLs . These could be subs of 6NO90 if they do exist ! But caution :
Don't use these to switch directly HV !! As TEKTRONIX did , they turn a low voltage relay on to avoid arcing .

[Scott_fx]

would 12v be considered high voltage? does it matter that it's going to be low amperage?