5 volt DPDT Realys??? Where ??

e30_droptop · 04-30-2006, 07:31 PM

I am looking for and have searched for a good 5 volt Double Pole Double Throw relay for a project I am building, but have not been able to find one.

Ratshack has a SPST 5 volt relay , but no DPDT's???

jayearl · 04-30-2006, 07:48 PM

How about: 255-1116-ND (Digikey part numer)
www.digikey.com

e30_droptop · 04-30-2006, 08:34 PM

Good find! Its 5 Amp rated. Wonder if a car retractable antenna is going to pull more than 5 amps?

Scouse Monkey · 04-30-2006, 08:36 PM

i doubt it. but have you checked to see if the antenna is already powered by an automotive relay? if it is then power this relay with the 5V one by switching the 12V supply to the relay. or jsut add a 12V automotive relay.

e30_droptop · 04-30-2006, 08:44 PM

Quote: Originally Posted by Scouse Monkey

i doubt it. but have you checked to see if the antenna is already powered by an automotive relay? if it is then power this relay with the 5V one by switching the 12V supply to the relay. or jsut add a 12V automotive relay.

Thanks for the reply Scouse.

I pulled the Antenna out of the vehicle and am using it in a custom way. I will be using it to actuate a sliding door. So at this time there is not a relay powering the antenna. I do need one that I can flip flop the output on as the antenna needs to see voltage on the green wire and gound on the red wire to go out and vice versa to retract. I want 5 volts as an output as the antenna moves slower powered by 5 volts. That will allow for a smoother slide.

I think I will just go with the suggested relay as it should fit the bill.

Scouse Monkey · 04-30-2006, 08:49 PM

no worries. you should be fine with 5A. you could do a few tests with an ammeter to be sure or actually i would add a 5A fuse to be safe - afterall it is a motor and should be fuses.

e30_droptop · 04-30-2006, 09:03 PM

Yeah. Then if I apply 5 volts and it blows the 5 amp fuse . well then I guess that would be an unmistakable way of determning that the antenna draws more than 5 amps. I have a standard DMM and wonder if I can use that to determine amps?

Scouse Monkey · 04-30-2006, 09:08 PM

depends how much it can take. it will tell you. they often have a 10A load these days. YOu could always pick up a cheap 10A moving coil ammeter or just try it with a 5A fuse!

e30_droptop · 04-30-2006, 09:39 PM

Ill try it with the fuse, - thats super cheap to try out. I will even offer some resistance to the antennna mast to make the motor work harder and see if that increased current draw causes the fuse to blow.

Scouse Monkey · 05-01-2006, 04:56 AM

yeah make sure you put it under load.

JC-S60 · 05-01-2006, 06:03 AM

Quote: Originally Posted by Scouse Monkey

yeah make sure you put it under load.

Indeed, try to block it and see what it does then... I'm guessing there is no thermal protection built in, so you'll need a fuse if you don't want fire

e30_droptop · 05-02-2006, 02:20 PM

The car antenna does have a built in clutch so it will just sit there and keep turning against the load endlessly unless there are limiting switches used-which I plan on using. I just wanted to see what the current did when it hit this loaded condition. I bet it increases some and then drops out slightly as every clutch revolution takes place. I intend on placing a fuse inline for sure though! Thanks for the suggestions.

Scouse Monkey · 05-02-2006, 02:54 PM

when on the clutch it will still use more power as the resistance will be high. jam it and use it as a worst case scenario.

JimmyFitz · 05-02-2006, 09:51 PM

If your antenna draws more than 5A the relay rated for that will still work BUT here is what will happen:

Every time you break the circuit (by switching the relay) an arc will occur. Over a period of time it will burn the contacts until it either won't make connection again, or it will weld shut and won't break connection. Murphy likes to make sure that happens when it is least convenient to you. The fuse won't prevent this from happening. I suggest you check the current draw on the motor at the voltage you will be using and get a relay that has a rating that is 20-50% higher at least.