Selecting SPDT Switch for 24V Supply Voltage

  • Thread starter braren
  • Start date
  • Tags
    Switch
In summary, the relay is getting hot because it is being overvoltaged. Make sure you are using the correct voltage for the relay.
  • #1
braren
5
0
Hi,

I'm working on a project where I need to use a couple of relays to send an input signal back to the controller. I'm using the 24V supply voltage from the controller to power a spdt switch, but I noticed that if I keep the switch powered for awhile, it gets hot to the touch.

The specs for the switch are...
Product Height 1
DC Coil Voltage 12
Coil Resistance 270
Max Current Rating 5
Max AC Voltage Rating 250
Max DC Voltage Rating 30
Average Bias Current-Max (IIB)(uA) .003

I know that some components will get a little hot when running under normal conditions, but I guess I'm just not sure if I'm overloading the switch. The specs say that the DC Coil Voltage is 12V, but the Max DC voltage is 30V. Does this mean I can put 30V across the coil and be fine? My next step is going to be measuring the current through the coil when operating, but what kind of calculations or otherwise should I do with that? As long as the current is under 5A, I should be good right?

Thanks for the help!
 
Engineering news on Phys.org
  • #2
Are you referring to a relay?
If you are, then the coil can only be powered by 12 vdc. The 30 vdc/250 vac is for the switch contact. Your relay is probably getting hot due to overvoltage on the coil.
If you are going to use 24 vdc to power it, get a relay with a 24 vdc coil.
 
  • #3
The coil voltage is 12 volts DC and that is the end of it. You are doubling the specified voltage on the coil. The other voltage ratings are for the relay contacts. If you know ohms law you can tell what the coil current should be by the coil resistance spec and the voltage applied to the coil.
 
  • #4
Sorry, yeah, I was referring to a relay not a switch, I have this bad habit of using the words interchangeably :P

The reason I was testing this relay with my system was because when I first wired everything up, I had a 24V relay that, although wired correctly, would not switch over when I applied a voltage to it. I don't know if this is because it was trying to pull more current than was available or what, but I changed some wiring in my circuit (jumpered the supply voltage for the digital Input and outputs together) and swapped the 24V relay back in, and now it's working!
 

1. What is a SPDT switch and how does it work?

A SPDT (Single Pole Double Throw) switch is an electronic component used to make or break the connection between two circuits. It has three terminals - the common terminal, the normally open terminal, and the normally closed terminal. When the switch is in the "on" position, the common terminal is connected to the normally open terminal, and when the switch is in the "off" position, the common terminal is connected to the normally closed terminal.

2. How do I choose the right SPDT switch for a 24V supply voltage?

When selecting an SPDT switch for a 24V supply voltage, it is important to consider the maximum voltage and current ratings of the switch. The maximum voltage rating should be equal to or greater than 24V, and the maximum current rating should be equal to or greater than the maximum current that will flow through the switch. It is also important to consider the type of load that will be connected to the switch and choose a switch with an appropriate switching capacity.

3. What factors should I consider when choosing an SPDT switch?

Aside from the voltage and current ratings, there are a few other factors to consider when selecting an SPDT switch for a 24V supply voltage. These include the type of load (inductive or resistive), the switching speed (how quickly the switch can change state), the operating temperature range, and the expected lifespan of the switch.

4. Can I use a SPDT switch with a different supply voltage?

It is possible to use a SPDT switch with a different supply voltage, but you must make sure that the switch can handle the new voltage and that the load connected to the switch can also handle the new voltage. It is always best to choose a switch with a voltage rating that matches the supply voltage for optimal performance and safety.

5. Are there any additional features I should look for in a SPDT switch?

Some SPDT switches may come with additional features such as a built-in LED indicator, a waterproof or dustproof casing, or a lockable toggle. These features can be useful in certain applications, but they may also add to the cost of the switch. Consider your specific needs and budget when deciding which features are necessary for your project.

Similar threads

  • Electrical Engineering
Replies
8
Views
1K
  • Electrical Engineering
Replies
13
Views
1K
  • Electrical Engineering
Replies
15
Views
1K
Replies
48
Views
3K
  • Electrical Engineering
Replies
23
Views
2K
  • Electrical Engineering
Replies
1
Views
148
  • Electrical Engineering
Replies
6
Views
807
Replies
11
Views
2K
Replies
7
Views
1K
Replies
31
Views
2K
Back
Top