Jump to content

Relay for wiper motor


Recommended Posts

I have a wiper motor from MonsterGuts that I picked up last year.  I noticed if I had it running sparingly, that I had no problems with the show.  If it was on consistently, then my show started acting up.  Back then, someone had suggested a relay.  Can someone help me with what I'm looking for?  Thanks.

Link to comment
Share on other sites

  • 4 weeks later...

Wiper motors usually are 12 Volt DC, I would assume that what is happening is you are running DC boards (for your Monster) and the motor is driven directly from the board ?

 

To get around the large drain the motor places on the power supply,  Using a relay is a common way.

 

A relay is a coil that when energized, will throw a switch, the switch is isolated from the drive coil, so in effect you can have 2 different voltages (even AC on the switch (contacts), HOWEVER, remember that the AC has to be treated just like the stuff in the wall plug, (no loose or bare wires kinda thing).

 

Usually  there are at least 4 terminals for a basic relay (2 for the coil, 2 for the contacts (switch)). this would be called a spst (Single Pole Single Throw)

 

Some relays get quite complex, and can get up to 4pdt (4 Pole Double Throw), However, for your application, a standard automotive "Cube" relay should work.

 

SO, I am going to ask this... What is driving the wiper motor ? are you using a LOR 16 contrller and a battery charger ? OR, is everything 12 volt DC in the first place ?

 

Greg

Link to comment
Share on other sites

True, but you can use a cheap radio shack relay to drive the motors powersupply, and this will isolate it from the controllers supply, the relay would however have to be an AC coil type, and I would put a  resistor say 47K ohm, 1 watt , across the coil terminals so it has something to "sink" the  inductive spike into, instead of blowing a triac on the controller....

 

The above would depend on WHAT controller he (She ??) is using to control that wiper motor......

 

Greg

Link to comment
Share on other sites

Well.... First off, if you are running a 12VDC motor from a relay, you need to make sure of a couple of things if you want reliable operation.

  1. The relay contacts have to be rated for the motor load you are using or they will not last very long.  Motors have a large inrush current when they start and that requires contacts that are made to handle it.  The contacts also have to be rated for DC operation.  DC is 100% duty cycle as opposed to AC which has a zero crossing point every 1/2 cycle and therefor will quench an arc much easier than DC.  Most decent power relays will handle up to 28VDC if you don't exceed the contact rating for current of an inductive load.
  2. The coil voltage must be rated for the voltage you are using to trigger it.  In your case I believe that would be 120vac.  As for the resistor across the coil, that is only half right.  you should either use a real "snubber" (not what is referred to as a "snubber" on the Christmas light forums).  The snubber should be an RC or resistor in series with a capacitor.  You can buy them already made in a single package but if the coil is small enough, you will find that the triacs in the controllers will handle them without such a snubber.. But the recommended setup would be with that RC snubber.

OR

 

You could use a SS (solid state) relay that is rated for this operation.  There is no inductive kick because there is no coil.  There are no switching contacts so there is no arc pitting of those contacts like with a regular dry contact type relay.  You just have to make sure you use the right relay. 

Link to comment
Share on other sites

Why do people use LOR to control their motors?  I've seen this topic brought up in the past and i've never understood why you would go through the hassle, not to mention eating up channels.  I've always used motors in my show for my props, but i simply have them on $10 timers from walmart.

Link to comment
Share on other sites

Why do people use LOR to control their motors?  I've seen this topic brought up in the past and i've never understood why you would go through the hassle, not to mention eating up channels.  I've always used motors in my show for my props, but i simply have them on $10 timers from walmart.

For one, it is simple to do.. It is also a way to turn things on and off when you want them to be part of a programmed show.  Not every motorized "thingy" is a run an forget type of setup.  I am actually going to incorporate some either air solenoids or motors in my show this year for some special effects.. I will be using the LOR controllers to handle them because I want them to operate when I need them for the show and no other time..

 

It just makes sense..

Link to comment
Share on other sites

Gotcha!  In my experience i've either had the props occupy one side of the yard as to not interfere with the LOR show....or i've incorporated lights around the prop.  For instance, my skating rink was something i had on all the time. People are more drawn to the motorized props than the lights (again only speaking from my experience) so i built light poles to bend over the top of the rink to "encapsulate" the skaters/rink.  I had 8 light poles with 4 channels each.  This way i was able to keep the ferris wheel, the skating rink, and this year a toy conveyor machine going at all times in harmony with the lights.  From your description it sounds like you do the opposite...building props into the light show.  I get it. 

Link to comment
Share on other sites

Gotcha!  In my experience i've either had the props occupy one side of the yard as to not interfere with the LOR show....or i've incorporated lights around the prop.  For instance, my skating rink was something i had on all the time. People are more drawn to the motorized props than the lights (again only speaking from my experience) so i built light poles to bend over the top of the rink to "encapsulate" the skaters/rink.  I had 8 light poles with 4 channels each.  This way i was able to keep the ferris wheel, the skating rink, and this year a toy conveyor machine going at all times in harmony with the lights.  From your description it sounds like you do the opposite...building props into the light show.  I get it. 

Yes.. I have done only lights for the last 3 years.. this year I want to add some mechanicals to the mix.. Hopefully I will get it done. 

 

Funny you should mention "drawn to the motorized props than the lights".   My plan is to hide my big ball inside a present and then draw attention away from it with lights at the other end.. then drop the present side walls to expose the ball and run its lights.  We shall see how that goes..

Link to comment
Share on other sites

Gotcha!  In my experience i've either had the props occupy one side of the yard as to not interfere with the LOR show....or i've incorporated lights around the prop.  For instance, my skating rink was something i had on all the time. People are more drawn to the motorized props than the lights (again only speaking from my experience) so i built light poles to bend over the top of the rink to "encapsulate" the skaters/rink.  I had 8 light poles with 4 channels each.  This way i was able to keep the ferris wheel, the skating rink, and this year a toy conveyor machine going at all times in harmony with the lights.  From your description it sounds like you do the opposite...building props into the light show.  I get it. 

In my experience if you have just a light show people love it, if you have just a motorized display people love it, but combine the 2 like I did the last few years and the sequenced lights aren't as popular. In my area we were the only ones to build motorized characters, a few did lights shows, so people were always drawn to the character first because it's not something they see all the time

Link to comment
Share on other sites

In my experience if you have just a light show people love it, if you have just a motorized display people love it, but combine the 2 like I did the last few years and the sequenced lights aren't as popular. In my area we were the only ones to build motorized characters, a few did lights shows, so people were always drawn to the character first because it's not something they see all the time

Unless of course you sequence as good as I do!   :P :P :P:D:rolleyes:

Link to comment
Share on other sites

It's doesn't matter how good my sequencing gets, not very good at this point, it will never match up to what I can do with a paint brush and a motor. All thought I'm pretty pleased with my new Olaf I'm building, my son go nuts for it

Decided to try something new and ditch the wood and motor on this one lol.

Link to comment
Share on other sites

 It's doesn't matter how good my sequencing gets, not very good at this point, it will never match up to what I can do with a paint brush and a motor. All thought I'm pretty pleased with my new Olaf I'm building, my son go nuts for it ..Decided to try something new and ditch the wood and motor on this one lol.

I have to admit.. I wish I was good with a paint brush..  I envy those that can make a piece of wood come alive with color and an image.. But.. since I personally don't have the talent.. all I can do is do what I can do.. and lights B it!  I love me some light!   :D

  • Like 1
Link to comment
Share on other sites

Generally that problem happens when running a motor off of an AC controller, wiper motors can be ran off of 12v or 5v power supplies

 I am using Monster Guts' 12 v AC adapter, if memory serves.  The interesting part is that if I run it sparingly when plugged directly to a channel, everything is fine.  It's only an issue when I have it on a lot.  That's why I was looking for a relay.  I just have zero idea of what I'm looking for.

Link to comment
Share on other sites

What I'm seeing in this is that the ac adaptor is doing both the monster AND the wiper motor, IMO this is too much for the adaptor, what you need is a 2nd adaptor (or a battery eliminator) that power ONLY the wiper motor....

 

Most wiper motors are about 3 amps @ 12-14 volts.

 

If you could find an AC adaptor that is the same rating as the one you are now using, and seperate the motor from the rest if it, that should fix the problem.

 

Greg

Link to comment
Share on other sites

The LOR showtime adapter has an AC adapter plugged into one channel. That adapter connects directly to the wiper motor. The odd behavior involves other channels not turning on/off correctly.

Link to comment
Share on other sites

What I'm seeing in this is that the ac adaptor is doing both the monster AND the wiper motor, IMO this is too much for the adaptor, what you need is a 2nd adaptor (or a battery eliminator) that power ONLY the wiper motor....

 

Most wiper motors are about 3 amps @ 12-14 volts.

 

If you could find an AC adaptor that is the same rating as the one you are now using, and seperate the motor from the rest if it, that should fix the problem.

 

Greg

It's a 120v ac to 12v DC adapter that they sell to run the wiper motors. That is odd, I would think turning it off and on would cause the issues, motors use a higher draw while starting then when running. Unless it's drawing too much amperage and not leaving enough left for the other channels. Are channels not operating correctly? Random flashes? Ect?

Link to comment
Share on other sites

....... Unless it's drawing too much amperage and not leaving enough left for the other channels. Are channels not operating correctly? Random flashes? Ect?

aaahhh... I doubt this is the case..  More likely power supply switching noise as the motor gets hotter... (though I can't even imagine that one)  Could be the supply cycling for thermal reasons and the instant start up under load causes the problem... .. could be a number of other things.

 

Rather than spend a great deal of time figuring this out, I agree that you should get a relay to isolate it from the LOR controller... but if you power it from the same source as the controller you may still get the issues..  Without seeing it hard to tell.

 

So now if you do use a relay to isolate it, and you if you have to use another power source, it becomes a bit of a pain.  You may even try a bigger power supply or a line filter between the LOR controller and the power supply for the motor.  To me, the correct thing to do would be to plug the motor supply into the regular power and control the DC with a relay.  That way you are not getting the supply start up in rush all the time.

Link to comment
Share on other sites

I do not have a separate power source available.  The LOR takes up the only source available at that location. 

Ok..then with the limited info posted, I would suggest getting a supply that will handle more current and using a relay to switch the DC side instead of switching the AC side as you are doing now.   That is about as good as you can do with what you have available to you.

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share

×
×
  • Create New...