Ok guys, I need some help from the experts. I've built a home theater that utilizes four Firgelli actuators that operate simultaneously. Each 12v actuator pulls 5amps each and have built in limit switches. These are all triggered by the contact closure in a Global Cache GC-100-12. The power supply powering the actuators is rated 30amps at 12v. I'm assuming all my wiring is correct because everything works and functions fine. My only problem is the DPDT relay. It gets WAY too hot. My question is what size/brand/type of DPDT relay do I need and where can I get it????

 

What relay do you have now and what is the voltage used to actuate the relay coil?

 

I used a 5amp 28VDC socket style relay I had laying around just to see if everything would work properly. Then I bought a 30amp 28VDC. Funny thing is, the 5amp worked way better than the 30amp. The 30amp relay got extremely hot and started buzzing in a matter of minutes.

All the spec sheet says about the contact closure is
"3 Integrated Contact Closure Relays w/ transient voltage suppression
Screw terminal 24V AC/DC@.5A N.O. contact
Allows for control and monitoring of in-line, low voltage wiring
Possibilities include: pools/spas, garage doors, irrigation, etc."

 

If you use 28VDC to actuate the relay there should be no buzzing.
What is the voltage and type (AC/DC) that you are using to actuate the relay?

 

12V DC if I'm understanding correctly. Sorry for more lack of electronic knowledge...lol

 

12V DC if I'm understanding correctly. Sorry for more lack of electronic knowledge...lol

But you state the relays are 28VDC.
If so they should be activated with 28VDC, not 12VDC.

Relays have two ratings, the coil rating, and the contact rating, and they are usually different.
You need to state both ratings.

 

This can go on for another 20 posts and get nowhere. Try this:
What is the make or manufacturer of the relay?
What is the part number or model number of the relay?
Where did you buy it?
Post a link to a data sheet.
Post a photo.

ak

 

30A 250VAC
30A 28VDC

 

 

That's not the coil rating.

 

We're getting off topic.

Four actuators at 5amps max
12v 30amp power supply
Using a contact closure

What DPDT relay do I NEED?

 

We're getting off topic.

Not quite.
Will you be using 12Vdc to actuate the relay?

 

I think OP is feeding 12vdc into the "Global Cache GC-100-12" that has a NO relay rated at 24vdc at 500ma to close the external high amp relay.
Slate, can you post a diagram of how you have all this wired up, and maybe the model of the relay you bought as the photo is unclear.

 

The part number is on the relay in the photo the OP posted in post #9.

P/N JQX-12F-2Z

http://www.langirele.com/htm/power-relay.htm

 

We're getting off topic.

Four actuators at 5amps max
12v 30amp power supply
Using a contact closure

What DPDT relay do I NEED?

Hi

What is not clear and not shown on your photo is the coil voltage.
Knowing that would help solve this mystery.

A drawing of the wiring would also help.

When you bought the relay, what did you specify as the coil voltage?

JQX-12F-2Z-(??) ??=coil voltage

 

If I'm reading the spec sheet right, at 12 volts, 120Ω (coil resistance) that's 100 mA (milli-amps), and 1.2 watts. The wattage thing is what creates the heat. Perhaps another resistor in series with the coil will drop the amperage. What resistor to use? I don't know for sure. The coil will require a minimum current in order to pull the contacts from NC to NO, so you may have to experiment. Also keep in mind the wattage rating of the resistor. For starters I'd substitute a 35 watt car bulb in series. The bulb will have somewhere near 5 ohms at 35 watts / 12 volts. The relay should run a little cooler. A lower wattage bulb will have a higher resistance and the relay should run even cooler yet. Perhaps a dash board light or a side marker bulb. I'll look up side marker bulbs on an auto parts store website to see what their wattages are.

 

http://www.autozone.com/electrical-...t-mini-bulb/493802_0_18269_2805?checkfit=true

This bulb has an amperage draw of 0.35 amps (350 mA). It's resistance would be about 34.3Ω. 350 mA (times) 12 (volts) equals 4.2 watts. Not a lot of light and capable of dissipating over 4 watts.

Calculating total resistance through the circuit (relay and bulb in series) would be 154Ω. At 12 volts the current (amps drawn) would be 78 mA (0.078 A) for a total of 935 mW. That's less than 1.2 watts, which will mean less heat generated. OR you could go buy some 5 watt resistors in the range of 50 to 200 ohms and try them to see how well the relay operates without generating excessive heat.

It's all in the numbers. And numbers aren't always my best suit, so someone will graciously correct me if I'm wrong. OR if someone has a different point of view, I'm certain they will point out ways they feel may better suit your situation.

 

The coil voltage is sometimes shown at the top of the relay, or on another side. As has already been mentioned, it's critical to use the right coil voltage for its proper operation, otherwise the thing will overheat and melt... it could even catch fire! Also, try to measure the voltage being delivered to the coil with an MM.

 

Those relays also come in AC coil, if using this variety and are used on DC they overheat.
Max.

 

OK, we are not getting the full picture. In one case the OP/TS just wants it to works and in the other the community wants to understand what's wrong.

GC says the contacts are rated at 0.5A 28 V AC/DC. Good.
Your relay is rated at 30 A, 28 V good.
With a 12 VDC version of the relay, the coil current is < 0.5 A -- good

The coil voltage and AC/DC for your relay is unknown. Bad for us.

The two possible conclusions with the amount of data available:
1) The power supply ripple is too high (not likely).
2) The relay coil voltage is incorrect.
3) The space lacks ventilation. In an enclosed space 3 * 5W is about 15W which is a fair amount of heat. To get a handle on it, it's 2 7W nite lights.

The full part number for the relay is necessary before we can proceed. We might ask for the power supply specification link too. A relay with a 12 V coil should work.

Aside #1: You should provide some sort of transient protection on the DC rated relay coil which is usually a reverse biased diode on the coil. For long contact life, particularly the contacts in the GC unit are protected based on their datasheet.

Aside #2: I selected some 24 VAC solenoid valves that were manfoldable for use on unlucubrated air and they buzzed. The solution was to take the brand new valves apart and clean them. Dust was causing them to vibrate.