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[ChrisinSantaFe]

I am installing an evaporative cooler on my house and would like to take advantage of Active Home Pro and X-10 control modules to control my cooler.  The unit has a 1 HP motor with three wire connections.  Common and two switched 120VAC connections.  One connection runs the motor at low speed the other at high speed.  I looking for ideas on how to accomplish this.  I am wanting to install the control modules on my roof.  I can add an electrical box to accommodate the control modules (and contactors if necessary).  Right now I simply have an outdoor J-box that houses two duplex outlets.

Any suggestions would be appreciated.

Chris

[Mike C]

You may want to take a look at this relay module from smarthome.  Here is some info.
http://www.smarthome.com/1289.html

1289 30-AMP APPLIANCE RELAY MODULE

Save a fortune on your utility bills by running heavy appliances at off-peak hours
Comes with an ON/OFF button -- control appliances remotely or locally
Doubles as an X10 signal bridge -- get two products for the price of one

 

If you've been looking for an X10 appliance module powerful enough to handle loads higher than 20 amps, you're in luck! Due to popular request from Smarthome customers, we now offer an X10 module powerful enough to handle appliances rated as high as 30-amps. Use it for controlling electric water heaters, air conditioners, baseboard heaters, and other heavy-duty appliances up to 7,200 watts!

[dave w]

ChrisinSantaFe
You don't say how your fan speed is changed normally.
Do you want to control fan ON-OFF and speed by X10? If so, one way of doing it is two appliance modules, each controlling a 20 amp DPDT relay with 120VAC coil.

Use one relay to apply power and the second relay to determine which motor winding the power is applied to. That way even if you accidently turn ON both appliance modules, you won't be applying power to both  high AND low speed windings.

 

[steven r]

...Use one relay to apply power and the second relay to determine which motor winding the power is applied to. That way even if you accidently turn ON both appliance modules, you won't be applying power to both  high AND low speed windings....

I was straining my brain to try to figure out how you would use X10 and keep from turning on both motors. I was thinking in the "ON/OFF" box. Simply thinking a bit out of the box solves the problem.

[ChrisinSantaFe]

The motor has three connections.  One is common the other two are to run the motor at low or high speed.  Apply 120 VAC to one pole and the motor runs at low speed.  Apply 120VAC to the other and the motor runs at high speed.  Both low speed and high speed are NOT energized at the same time.  I am beginning to think that I need a latching relay to select between the low and high speed connection and another to deliver 120VAC to that latching relay. This to control the motor on/off and the speed.  I will add another relay to control the water pump inorder to run the unit just as a fan or as an evaporative cooler.  I hope this provides some clarity.

Thanks for the suggestions - welcoming more after my clarification.

Chris

[steven r]

...I am beginning to think that I need a latching relay to select between the low and high speed connection and another to deliver 120VAC to that latching relay. This to control the motor on/off and the speed.  I will add another relay to control the water pump in order to run the unit just as a fan or as an evaporative cooler....

Sounds like you've got things figured out. You might want to make sure you're not pumping water when the motors are off also. (Would that cause a problem?) As dave w suggested, the relay to select low or high speed is the safest way to go. Otherwise you risk turning both on at the same time.

I'd be curious as to what kind of controller someone would use if they weren't going to set it up with X10 control.

What kinds of energy savings can one expect with an evaporative cooler? Expected time to recover an investment?

[ChrisinSantaFe]

Thanks for the useful comments!  Steve to answer your question about evaporative cooling - it is of course only effective in a dry climate.  In the southwest one can expect 1/4 of the energy consumption of a conventional refrigerated air conditioner.  I am looking to add a humidistat and thermometer to my x-10 to optimize the system.  Any suggestions on available modules?  I will probably follow Dave's advice and use two relays - one for on/off the other for speed selection.  To that end I will look for an X-10 module that can either supply or switch the 24 V power required to opperate the relays.  Not sure what is available in this regard either from X-10 or smarthome.  Something with 3 adressable output would be ideal.  The reason for a separate control on the water pump is to allow for wetting the pad before you start the fan.  Otherwise you just blow hotair initially.

Chris

[steven r]

...To that end I will look for an X-10 module that can either supply or switch the 24 V power required to opperate the relays....

If you are just going to need to switch low voltage relays, check out this.
It could be easier than using multiple 120 VAC controllers.

[dave w]

Chrisinsantafe
Chris said
"I am beginning to think that I need a latching relay to select between the low and high speed connection and another to deliver 120VAC to that latching relay."

You really don't need latching relays. Pretty hard to find and usually expensive. You can use 120v AC coil relays like these from Radio Shark.

125VAC/10A DPDT Plug-In Relay  
Model: 275-217  |  Catalog #: 275-217

By parallelling both poles you could control up to 20 amp. Use one relay to switch between high speed and low speed windings (NO contacts to one winding and NC contacts to the other winding) and the second relay connects power to the common terminals of the speed relay. If you do want to use 24V relays you could use X10 "Universal" modules UM506 (http://www.x10.com/automation/um506_s.html) to control each relay.

Usually I can find 120 VAC coil relays cheaper (>$2.00) than the 9 bucks Radio Shark wants at surplus houses like

http://www.allelectronics.com/
http://www.goldmine-elec.com/
http://www.meci.com/

but there must be a run on 120VAC relays, because all seem to be out of stock.